page 24: Is there an alternative to field theory?
If you are receptive and humble, mathematics will lead you by the hand. Again and again, when I have been at a loss how to proceed, I have just had to wait until [this happened]. It has led me along an unexpected path, a path where new vistas opened up, a path leading to new territory, where one can set up a base of operations, from which one can survey the surroundings and plan further progress. Graham Farmelo (2009): The Strangest Man: The Hidden Life of Paul Dirac, Mystic of the Atom, page 435
A physical understanding is completely unmathematical, imprecise, an inexact thing but absolutely necessary to a physicist. Richard Feynman: Lectures on Physics II Chapter 2: Differential Calculus of Vector Fields
The rules of renormalization give surprisingly, excessively good agreement with experiments. Most physicists say that these working rules are, therefore, correct. I feel that that is not an adequate reason. Just because the results happen to be in agreement with observation does not prove one's theory is correct. . . . I have spent many years searching for a Hamiltonian to bring into the theory and have not yet found it. I shall continue to work on it as long as he can, and other people I hope will follow along such lines. Peter Goddard (1998), ed. Paul Dirac, The Man and His work, page 28
I'm not happy with all the analyses that go with just the classical theory [of computation], because nature isn't classical, dammit, and if you want to make a simulation of nature, you'd better make it quantum mechanical, and by golly it's a wonderful problem, because it doesn't look so easy. Feynman (1981): Simulating Physics with Computers
Table of contents
24.1: Data and explanation
24.2: John von Neumann: Mathematical Foundations of Quantum Theory
24.2: Cantor: one to one correspondence ≡ locality
24.3: What is a physical field?
24.4: Wilczek: what is the world made of?
24.5: What is real: particles or fields?
24.6: The representation of reality: theory and the entropy of explanation
24.7: Physics is an empirical foundation for theology
24.8: Symmetry with respect to complexity
24.1: Data and explanation
In scientific investigations . . . it is permitted to invent any hypothesis, and if it explains various large and independent classes of facts, it rises to the rank of a well grounded theory. Charles Darwin (1875, 1998): The Variation of Animals and Plants Under Domestication
Karl Popper provided us with a rather straightforward account of scientific method in his book Conjectures and refutations. Faced like Darwin with a body of data we begin to dream up stories to explain the data. Then we test our explanations with more data, searching for weaknesses. Darwin saw that the beaks of the finches on different Galapagos islands were different. Was this just a random event, or could it be explained by the different sources of food on different island? He made his case for evolution by collecting more and more data from diverse sources until his story became, as we now know, irrefutable. Karl Popper (1972): Conjectures and Refutations: The Growth of Scientific Knowledge
Nearly thirty years later, after the invention of the internet, Fortun and Bernstein give us a messier view of science. Now a large population of internet users are making up stories about every event in the news, and not all of them are dealing with hard evidence collected under controlled conditions. Now much of the data is gossip, and there is no constraint on conjecture. Known chronic liars and perpetrators of blatant falsehoods are becoming wealthy. The fringe is threatening the mainstream. Since accountants have taken over academia and the key guideline has become publish or perish, we find that incentives for scientific fraud are growing. Fortun & Bernstein (1998): Muddling Through: Pursuing Science and Truths in the Twenty-First Century
Fortunately reality still rules, so truth continues to prevail against the noise. Old evils like imperialism, corruption, racism and sexism are under fire, their failures being made manifest by the repressive behaviour of old guard who are struggling to maintain their privileges. The citadels of power are leaking. New media are giving us all a voice.
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24.2: John von Neumann: Mathematical Foundations of Quantum Theory
Philosophy is written in this grand book - the universe, which stands continually open before our gaze. But the book cannot be understood unless one first learns to comprehend the language and to read the alphabet in which it is composed. It is written in the language of mathematics . . . Galileo Galilei (1610, 1957): Discoveries and Opinions of Galileo: Including the Starry Messenger, p 238.
We may say that Old Quantum Mechanics began in 1860 when Gustav Kirchoff 's study of the radiation emitted by hot black bodies led him to formulate his law of thermal radiation:
For a body of any arbitrary material, emitting and absorbing thermal electromagnetic radiation at every wavelength in thermodynamic equilibrium, the ratio of its emissive power to its dimensionless coefficient of absorption is equal to a universal function only of radiative wavelength and temperature, the perfect black-body emissive power. Kirchoff's law of thermal radiation - Wikipedia
The search for the universal function took 40 years until in 1900 Max Planck found a function which matched the data collected by spectroscopists. The problem faced by previous efforts was that they predicted that the energy of radiation would increase with frequency, tending toward infinity, an ultraviolet catastrophe. Planck found that radiation is emitted in discrete quanta whose energy is a function of their frequency, E =hf, where h, now known as Planck's constant, is a new universal constant. The frequency of emission of individual quanta decreased as their energy increased, avoiding the ultraviolet catastrophe. Planck's Law - Wikipedia
Paul Dirac must be counted among the founders of quantum mechanics, the new paradigm that transformed physics and our view of the world. It is no longer inert matter but intelligent and creative. The consequences of the new physics run from the internet and mobile phones to nuclear weapons. Dirac, Galileo and just about everybody else would agree that mathematics lies at the heart of physics and physics has done a lot to ignite mathematics. Paul Dirac - Wikipedia
Maxwell's equations for electromagnetic radiation and the diffraction of light had convinced most people that light is a wave phenomenon so the first reaction to Planck's idea was that the quantization was not a property of the radiation but an artefact of the way it was emitted. In 1905 Einstein published a statistical argument that light was in fact particulate and used this idea to explain the photoelectric effect. Albert Einstein (1905c): On a heuristic point of view concerning the production and transformation of light, Photoelectric effect - Wikipedia
At the heart of mathematics we find Georg Cantor, the inventor of transfinite numbers, the person who brought infinity down to Earth by putting it in the boxes we call sets. Cantor laid the foundation for twentieth century mathematics by exploiting formalism, an idea as old as Plato (427 - 328 bce). Formalism in mathematics was popularized by David Hilbert the early in twentieth century. For Hilbert mathematics is a symbolic game in which anything goes as long as it does not lead to a contradiction. Plato - Wikipedia, Georg Cantor - Wikipedia, Hilbert's program - Wikipedia
Cantor worked in the context of the nineteenth century study of continuity which was intended to put differential and integral calculation on a firm footing. He digitized the study of continuity by using this theorem to approximate a continuum with integers in his desire to represent the cardinal of the continuum. He failed, but transformed mathematics in the process. On this site I understand a continuum to be a mathematical ideal that does not exist in nature. This is my principal reason for rejecting field theory and considering that physics must be the study of mappings between discrete particles, just as all communications are logical mappings between discrete sources. Classical computers share information by reading and writing to the same memory location. Quantum systems share information in the tensor product space of their individual wave functions. (see page 14: "Measurement": the interface between Hilbert and Minkowski spaces. In physics, as in mathematics, all interactions are local. Cardinality of the continuum - Wikipedia, Tensor product - Wikipedia
A central idea in mathematics is the function, often written y = f(x), it establishes a one-to-one correspondence or map between two sets of symbols, y and x. The xs are often called the domain of the function and the ys the range. The xs and ys may be any identifiable mathematical objects, numbers, vectors, tensors, matrices, sets and so on. Function (mathematics) - Wikipedia, Map (mathematics) - Wikipedia
Cantor identified two abstract features of sets, their cardinal number and their ordinal number. The cardinal number is the number of object or elements in the set. The ordinal number takes into account the order of the elements in the set. The cardinal and ordinal numbers of sets can be compared by establishing one to one correspondences between their elements, even, in principle, if the sets are infinite. The set of natural numbers is infinite because there is no last number: we can always add another one. Cantor invented a new symbol ℵ0 to represent the cardinal of the set of natural numbers. He proved that given any set, finite or infinite, there is always a set with a larger cardinal, Cantor's theorem. Cardinal number - Wikipedia, Ordinal number - Wikipedia, Cantor's theorem - Wikipedia
Cantor made a very bold claim when he presented his transfinite cardinal and ordinal numbers to the world. He wrote:
The concept of "ordinal type" developed here, when it is transferred in like manner to "multiply ordered aggregates", embraces, in conjunction with the concept of "cardinal number" or "power" introduced in [§1 above], everything capable of being numbered (Anzahlmassige) that is thinkable and in this sense cannot be further generalized. It contains nothing arbitrary, but is the natural extension of the concept of number. Georg Cantor (1897, 1955): Contributions to the Founding of the Theory of Transfinite Numbers, page 117
Cantor's ideas led to paradoxes in mathematics which motivated writers like Whitehead and Russell to try to develop a purely symbolic foundation for mathematics which would avoid the vagueness associated with natural language. While this approach helped remove the paradoxes it enabled Gödel to express his incompleteness theorems and Turing his theory of computation. This work established logical boundaries on formal mathematics which came as a surprise to Hilbert, who thought that consistent mathematics would be complete and computable. It also questions the applicability of mathematics to the real world. Some might feel that quantum computers can avoid Turing's restriction by solving problems beyond the power of Turing computation. Principia Mathematica - Wikipedia, Gödel's incompleteness theorems - Wikipedia, Turing's Proof - Wikipedia
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24.3: What is a physical field?
From a mathematical point of view, we may distinguish between a space and a field. A field is a function on space, so a space is the domain of a field. Space (mathematics) - Wikipedia
Auyang explains particle physics in terms of field theory as follows:
According to the current standard model of elementary particle physics based on quantum field theory the fundamental ontology of the world is a set of interacting fields. . . . There are 12 matter fields and each has an antifield. The 12 matter fields are divided into three generations; the higher generations are replicas of the first, except their quanta have larger masses. . . . All stable matter in the Universe is made up of only three matter fields in the first generation: electron, up quark and down quark fields. . . .
There are four fundamental interactions. Gravity. . .. Electromagnetism binds electrons and nuclei into atoms and atoms into molecules; the strong interaction binds quarks into nucleons and nucleons into atomic nuclei. The weak interaction is responsible for the decay of certain nuclei. . . .
Field has at least two senses in the physics literature. A field is a continuous dynamical system or a system with infinite degrees of freedom. A field is also a dynamical variable characterizing such a system or an aspect of the system. Fields are continuous but not amorphous: a field comprises discrete and concrete point entities, each indivisible but each having instrinsic characteristics. . . . The world of fields is full, in contrast to the mechanistic word, in which particles are separated by empty space across which forces act instantaneously at a distance. Sunny Auyang (1995): How is Quantum Field Theory Possible?
Fields are primary and particle are considered to be energetically excited states of the relevant fields.
In quantum mechanics the uncertainty principle tells us that the energy can fluctuate wildly over a small interval of time. According to special relativity, energy can be converted to mass and vice-versa. With quantum mechanics and special relativity fluctuating energy can metamorphose into mass, that is into new particles not previously present. Anthony Zee (2010): Quantum Field Theory in a Nutshell
This is the founding dogma of quantum field theory. It is made credible by the the results of the calculations that use it. But does mathematics fluctuate because there is uncertainty between the integers? A silly question. If the Universe is really a logical entity whose logical operations are represented in physical space by a quantum of action why should it be a seething mass of energy just because logical operations are discrete? The cosmological constant problem and the figures quoted by Wilczek below strongly suggest that there are features of reality that field theory fails to capture: page 18: Fixed points, laws and symmetries §7: The cosmological constant problem. Cosmological constant problem - Wikipedia
What are these fields made of? In the first instance, they are mathematical abstractions, functions like those described in §2 above. The conventional domain of these functions is spacetime. Their ranges are mathematical expressions generally characterized by the symbol φ which define properties of the particles that each field represents. According to the field picture, spacetime is overlaid by a dense layer of continuous mathematical functions defining the matter and interaction fields described in detail by Auyang.
In §24.4 below we skip through Wilczek's conception of what these fields might be made of. His account concludes with the the enormous differences between estimates of certain numerical properties of his massive grid and measured realities. These are reminiscent of the cosmological constant problem referenced above. There we discuss field theoretical calculation that differ from measured reality by numbers in the vicinity of 10100.
This result is a rather unfair misunderstanding of field theory, since it has internal mechanisms for dealing with infinities so that it yields results very close to what we actually observe, as the second part of Wilczek's book demonstrates. From the point of view of this site, quantum field theory is an effective system of calculation at what we might call an engineering level, but it seems to be a rather inconsistent representation of what is actually happening in the invisible world behind the scenes. Its basic problem is that it tries to explain an intelligent logical world in terms of arithmetic.
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24.4: Wilczek: what is the world made of?
Thermonuclear weapons are a byproduct of nuclear physics. The critical step came when Lise Meitner, Otto Hahn and Fritz Strassman discovered that neutrons caused some heavy nuclei to split and release a large amount of energy, nuclear fission. Nuclear fission - Wikipedia
Quantum mechanics developed rapidly early in the twentieth century under the influence of spectroscopic observations of the motions of atomic electrons. Nuclear interactions are approximately a million times more energetic than electronic interactions so the detailed development nuclear physics had to await the development powerful accelerators in the place of the spectroscopists bunsen burners. Once it was known that the U235 and Pu239 were fissile, the principal difficulty of creating the first few nuclear weapons was producing a few kilograms of these materials. Uranium-235 - Wikipedia, Plutonium - Wikipedia
The success of quantum field theory in quantum electrodynamics made it the natural choice for the development of nuclear theory. After considerable difficulty and a host of new insights field theory finally completed the standard model with quantum chromodynamics. This theory is the keystone of nuclear physics, explaining the internal structure of hadrons and mesons through the interactions of quarks and gluons. David Gross and Frank Wilczek won the 2004 Nobel prize in Physics for their contributions to this theory. Some of this work is described on page page 23: Insight and belief and their personal contributions are described in their Nobel lectures. Hadron - Wikipedia, Gluon - Wikipedia, Quark - Wikipedia, Standard model - Wikipedia, Quantum chromodynamics - Wikipedia, David J. Gross (2004): Nobel lecture: The Discovery of Asymptotic Freedom and the Emergence of QCD, Frank Wilczek (2004): Nobel lecture: Asymptotic Freedom: from Paradox to Paradigm
There can be no doubt that quantum field theory enables physicists to match their calculations to their observations very precisely, but the question remains: Are they really describing what is happening. At different points on this site I have pointed out what I see as deficiencies in quantum field theory, mainly relying on an article by Kuhlmann. Many of these problems arise from the connection between quantum theory and special relativity arising from the idea of quantum fluctuation described in the quote from Zee above. I am particularly interested in the cosmological constant problem which arises when we apply the assumptions of quantum field theory to the vacuum state. This issue is described in some detail on page 18: Fixed points, laws and symmetries §7: The cosmological constant problem. Meinard Kuhlmann (Stanford Encyclopedia of Philosophy): Quantum field theory
After working on quantum chromodynamics, Wilczek wrote a book to explain the consequences their discovery, reaching a conclusion which looks far worse that the original cosmological constant problem. Frank Wilczek (2008): The Lightness of Being: Mass, Ether, and the Unification of Forces
In Chapter 6 (page 32) The Bits Within the Its he describes his feeling about the role of mathematics in physics, quoting Heinrich Hertz who showed that Maxwells equations describe real entities:
On cannot escape the feeling that these mathematical formulae have an independent existence and intelligence of their own, that they are wiser than we are, wiser even than their discoverers, that we get more out of them than what was originally put into them. . . .
Wilczek continues:
The point I want to emphasize here, from the beginning . . . is that quarks and gluons, or more precisley their fields, are mathematically complete and perfect objects. You can describe their properties completely using concepts alone, without having to supply any samples or make any measurements.
Wilczek explains the consequences of this discovery, as he sees it:
For natural philosophy, the most important lesson we learn from QCD is that what we perceive as empty space is in reality a powerful medium whose activity moulds the world. . . .
The primary ingredient of reality contains a metric field that gives spacetime rigidity and causes gravity.
The primary ingredient of reality weighs, with a universal density.
Searching for a name for this entity, he rejects ether as being too old, dead and limited. He rejects space-time because carries a heavy suggestion of emptiness. Quantum field feels a bit technical for natural philosophy, so he chooses the term grid for the primary world-stuff (pp 74 – 75).
Wilczek proceeds to discuss the grid in great detail, introducing Newton, Faraday and Maxwell, who summarized Faraday's work in set of equations which explain the electromagnetic nature of light. Einstein introduced the key ingredient of special relativity: the speed of light is the same for all observers regardless of their inertial motion relative to the source of the light.
Einstein also proposed that light comprises particles and that special relativity renders Maxwell's ether field superfluous. We might be satisfied with a world of empty space with discrete particles moving about within it. Wilczek is concerned to save the grid (aka aether) however, and recalls a conversation he had with Feynman (page 83). Aether (classical element) - Wikipedia
They were discussing the cosmological constant problem. Wilczek recounts that Feynman told him he was disappointed with the outcome of his work on quantum electrodynamics. He had hoped that by formulating his theory directly in term of paths of particles in spacetime—Feynman graphs— he could avoid the field concept and construct something essentially new. For a while he thought he had. Why did he want to get rid of fields? "I had a slogan," he said, "The vacuum doesn't weigh anything because there's nothing there!".
Field remains with us still and Wilczek is its prophet!
He goes on to account Einstein's development of general relativity which, he says, is a field-based theory of gravity and concludes there's is a good general reason to expect that physical theories consistent with special relativity will have to be field theories:.
In special relativity the finite speed of light, illustrated by the light cone, means that the motion of each particle is controlled by events in its past. Light cone - Wikipedia
So Wilczek writes (page 86):
to get the total force on a particle, we have to sum up the influences coming from all the other particles coming from different earlier times. This leads to a complicated description (Figure 8.2b, page 87). An alternative is to forget about keeping track of the individual past positions and instead focus on the total influences, in other words to keep track of a field representing the total influence.
That move from particle descriptions to a field description will be especially fruitful if the fields obey simple equations, so that we can calculate the future values of fields from the value they have now without having to take past values into account. Maxwell's theory of electromagnetism, general relativity and QCD all have this property. Evidently Nature has taken the opportunity to keep things relatively simple by using fields.
This argument, he concludes, shows that fields are convenient. But are they necessary ingredients of ultimate reality?
Yes, he says, and the answer lies in vacuum polarization, ephemeral virtual electron-positron pairs that arise from quantum fluctuation and make small modifications to the deterministic predictions of Maxwell's equations. Field theoreticians believe that these modifications explain phenomena like the Lamb shift which led to the development of the quantum field theory that led to quantum electrodynamics. Vacuum polarization - Wikipedia, Lamb shift - Wikipedia, Shelter Island Conference - Wikipedia
This leads Wilczek to condensates: in the first instance quark-antiquark pairs, the chiral symmetry breaking condensate. He asks: why do we think this exists and how can we verify its existence?
The answer is that quark-antiquark pairs (aka σ mesons) exist because perfectly empty space is unstable. The reason is that σ mesons have negative total energy:
The mc2 energy cost of making those particles is more than made up by the energy you can liberate by unleashing the attractive force between them as they bind into little molecules. . . . So perfectly empty space is an explosive environment, ready to burst forth with real quark-antiquark molecules (page 91 sqq).
His next example of a condensate comes from the standard model of the electroweak interaction mediated by the heavy bosons W± and Z. This leads him to the Higgs condensate, the superconductor that may give mass to the heavy bosons. Electroweak interaction - Wikipedia
His new world is superlative: The entity we perceive as empty space is a multilayered, multicolored superconductor. What an amazing, astonishing, beautiful, breathtaking concept. Extraordinary too (page 97).
He then finds support from Einstein:
According to the general theory of relativity space without ether is unthinkable; for in such space there not only would be no propagation of light, but also no possibility of existence of standards of space and time (measuring rods and clocks), nor therefore any space-time intervals in the physical sense. Albert Einstein (1920): Ether and the Theory of Relativity
Encouraged by Einstein, he introduces The Mother of All Grids: [the] Metric Field (page 97). "Once it is expressed in terms of the metric field, gravitation resembles electromagnetism. . . . In general relativity the metric field bends the trajectories of bodies that have energy and momentum [?]." Newton explained the orbit of the Moon as the path balanced between the Moon's gravitational attraction to Earth and the centrifugal force arising from the Moon's curved path. Einstein (with Riemann's help) saw that no force is involved. The Moon is following a straight inertial path just as described by Newton's first law. The Moon's geodesic a continuous line of flat Minkowski spaces tangent io the curvature induced by the presence Earth. Riemannian geometry - Wikipedia
"Consistency [he says] requires the metric field to be a quantum field
like all the others. That is, the metric field fluctuates spontaneously." But, he notes, so far there is no evidence for this. Is the domain of the metric field some underlying spacetime, or is it the spacetime itself?
"Is the metric field a condensate (page 103)?" . . . This initiates a discussion of dark matter and the mass of the condensates. We finally get some numbers which are very reminiscent of the cosmological constant problem discussed at length on page 18.7 referenced above. The root of the problem is zero point energy and quantum fluctuation.
The quantum of action is a simple physical quantity whose units in Minkowski space are angular momentum. Its value has been measured with great precision. Some think it lies at the root of the uncertainty principle, but in reality, is is the fundamental certainty principle in the Universe, giving scale to everything else (see Principle 14: Quantization is a certainty principle, not an uncertainty principle).
Wilczek admits that in theory his list of condensates (pp. 109-110) deviate from measured reality by factors ranging from 1044 via 10112 to infinity and perhaps beyond. Does this mean that there is something wrong with the idea of quantum fluctuation? If there is how can we explain quantum field theory, particularly quantum chromodynamics, without it?
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24.5: What is real: particles or fields?
In the standard model fields are considered to be primary and particle are seen as energetically excited states of the relevant fields. Mathematical formulation of the standard model - Wikipedia
The reason for calling this site cognitive cosmology is that I feel that the ability of the Universe to solve what quantum mechanics understands to be the eigenvalue problem suggests that it is intelligent. A solution to an eigenvalue problem seems to be equivalent to an intellectual insight. It is a puzzle rather than a calculation. There has long been a question about whether mathematics is created by mathematicians or discovered. The Platonic view is that it exists independently of mathematicians, and is therefore discovered. Given the fact that the Universe began in a state of complete ignorance as a structureless initial singularity, the mathematics which we discover must first have been created by the Universe itself in the process of its evolution. Eigenvalues and eigenvectors - Wikipedia, Øystein Linnebo (Stanford Encyclopedia of Philosophy): Platonism in the Philosophy of Mathematics
Throughout this site I have been critical of field theory. I see it as an ad hoc scheme of computation which has been tailored over a century or so to give numerical results that closely track measurements. Nevertheless its methods may not necessarily reflect what is really happening.
The solution proposed here is to substitute what I like to call a Hilbert vacuum for the fluctuating vacuum of quantum field theory defined by the quotation from Zee in §3. This Hilbert vacuum is just the axiomatic Hilbert space and the associated theory of linear operators developed by von Neumann. We are able to use the non-relativistic form of quantum mechanics here because we are discussing an era before Minkowski space and the special theory of relativity came into existence. Hilbert space and quantum mechanics are an abstract kinematic mathematical structure driven by naked gravitation which identifies stationary points which are given dynamic particulate existence by energy derived from the bifurcation of gravitation into potential and kinetic energy described on page 17: Gravitation and quantum theory—in the beginning. We imagine that the bosons and fermions created by this process are the source of the Minkowski spacetime described on page page 12: The quantum creation of Minkowski space. John von Neumann (2014): Mathematical Foundations of Quantum Mechanics
We say that quantum mechanics is kinematic. It is a puppet, like all mathematics. It does not do itself, it has to be embedded in a dynamic system like a student's brain, a computer or reality to make it work. In the first instance this dynamic system is the initial singularity. I have called it naked gravitation since quantum mechanics has not yet developed the Minkowski space whose metric provides the foundation for general relativity.
On page 12: The quantum creation of Minkowski space we assume that Minkowski space is a product of the creation of Hilbert space and quantum mechanics described on pages 9: The active creation of Hilbert space and 10: The emergence of quantum mechanics.
Einstein, in his 1915 presentation of the field equations of gravitation notes that . . . the postulate of general relativity cannot reveal to us anything new and different about the essence of the various processes in nature than what the special theory of relativity taught us already. Albert Einstein (1915): The Field Equations of Gravitation
On page 12: I simply assumed that quantum mechanics operating in Hilbert space is capable of creating Minkowski space. Here I propose that the mechanism for this creation has an intermediate step, the creation of fermions and bosons. As I noted there, massless bosons travel on null geodesics, so there is zero interval between their creation and annihilation and this enables them to carry quantum states faithfully through space. The three spatial dimensions of Minkowski space are necessary to accommodate fermions which are massive dynamical particles.
This brings us to an interesting question: which fermions and bosons? Are they simple photons, electrons and positrons described by Dirac's equation, or are the heavier and more permanent structures of hadrons created in the high energy days of the Universe from quarks and gluons? The interesting thing about these particles is that they cannot exist by themselves, any more than a living species can exist without a supportive environment to provide it with food and shelter. So, we wonder, is the complexity of chromodynamics a necessary consequence of the fact that the proton, one of the first forms of life, contains a tiny self sustaining ecosystem which the evidence suggests may be eternal, that is capable of lasting forever if not destroyed by an outside agent. Are the hadrons the first fruits of the emerging Universe?
Physicists seem to be quite convinced that it is possible to represent any mathematical relationship in an equation. This idea clearly holds in a number of very simple cases like the quantum mechanical measure of energy E = hf or the Lorentz transformation. Here we assume that all the structures in the physical Universe, including ourselves have been formed by evolution and it seems well beyond the bounds of possibility to find an equation that represents the interaction between two people. In other words, we must be prepared to find physical relationships that are not amenable to simple mathematical relationships. The applicable formalism is more likely to be the theory of communication and coding involving specific codes or languages.
We might also wonder where mathematics and quantum is embodied in the Universe. Does a bag of beans contain or represent the arithmetic formalism necessary to operate on its contents?
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24.6: The representation of reality: theory and the entropy of explanation
Einstein wrote:
A theory is the more impressive the greater the simplicity of its premises, the more different kinds of things it relates, and the more extended its area of applicability. Therefore the deep impression that classical thermodynamics made upon me. It is the only physical theory of universal content which I am convinced will never be overthrown, within the framework of applicability of its basic concepts. Howard & Steichel (2000): Einstein: The Formative Years, 1879-1909 (Einstein Studies volume 8), page 1
Entropy is the simplest measure in physics, just a count with no dimension. Sometimes, for convenience it is espressed as a logarithm of the count. Shannon realized that it could also be used as a measure of symbolic text weighted by the frequency of the symbols. Given a source A with an alphabet of i symbols ai whose probability is pi, the entropy H of the source in bits per symbol is given by the expression:
H = Σi pi log2 pi
where Σi pi = 1
Entropy (information theory) - Wikipedia, Claude Shannon (1949): Communication in the presence of noise
As a matter of principle, we might expect the explanation of a natural phenomenon to have approximately the same entropy or complexity as the phenomenon itself. The complexity of explanations is radically reduced by symmetries so (eg) Newton's four laws that occupy less than 1k of text provide us with a quite complete description of classical dynamics. The detail enters through the application. We can say the same for other classical laws (symmetries) like Maxwell's equations, Minkowski space and Lorentz transformations and general relativity; the complexity comes from applications.
The power of knowledge arises from the condensation of many instances into simple rules. As children we soon learnt the relationship between heat and pain and approach potentially hot surfaces with circumspection, relying on their infra-red radiation to judge their temperature without contact.
We expect a similar symmetrical simplification in particle physics, so, given the simplicity of the early universe, we are justified in seeking very simple symmetries which are nevertheless broken and complexified in applications. So at the heart of QED and all the other fundamental theories we have the simple phase equations represented by the eigenvalue equation and the Born rule. These relationships hold in Hilbert space which, on the view taken on this site, is prior to and independent of special relativity so the fundamental quantum theoretical relationships operate independently. Special relativity only comes into play with the real dynamics of particles in Minkowski space.
Dirac and others, because they see Minkowski space as the domain of Hilbert space, see a need to for a continuous Hilbert space. Here, because we are treating Hilbert space and quantum mechanics as the computational basis for the behaviour of the world, we can avoid the difficulties involving continuity and infinity in quantum field theory and apply Hilbert spaces whose least upper bound is ℵ, ie C n. In their book on quantum computation, Nielsen and Chuang confine their work to finite dimensional Hilbert spaces (page 63). Nielsen & Chuang (2016): Quantum Computation and Quantum Information
We may say that the relationship between a theory and the corresponding reality is a messaging process which requires an equivalence of entropy or information between sender and receiver to achieve error free precision. Although Dirac and others attribute absolute precision to processes in continuous nature the practical application of notions such as the Dirac delta require smearing out the precision of real numbers. This reduces the precision to that of rational numbers. This precision may still within the grasp of quantum theory executed in C n space where n is a natural number. There is therefore no reason to suspect that nature needs recursive processes to achieve the precision that we actually observe and we can quite easily imagine the existence of eigenvalues that exactly represent the measured values of the Lamb shift. Streater & Wightman (2000): PCT, Spin, Statistics and All That, Lamb shift - Wikipedia
In his book quoted above Wilczek details the amount of conventional computation required to process a digital representation of the quantum mechanical processes inside mesons and hadrons: months of supercomputation to mimic real events that occupy tiny fractions of a second.
Two central features of quantum chromodynamics are asymptotic freedom and confinement. The deep inelastic scattering experiments described by Taylor, Kendall and Friedman on page 23 §6: SLAC and deep inelastic scattering indicated that the quarks appeared to move freely when they were close together. On the other hand, they were rigorously contained within the boundaries of their parent particles. This observation is explained in terms of the anti-screening made possible by the renormalizability of field theoretical interpretations of Yang-Mills theory. Martinus J G Veltman: Nobel Lecture 1999: From weak interactions to gravitation
We night wonder how nature achieves this result. One way to look at it would be to imagine that quantum computation in nature is at least as powerful as Turing computation and it has been possible to construct digital computations to explain quantum chromodynamics. How would quantum mechanics do it?
Could an evolutionary process construct such a structure: a linear operator with a spectrum sufficient to explain the working of a proton? On the assumption that the first living cells are more complex than the average hadron and almost certainly products of evolution, we must say yes. Furthermore, insofar as the quantum operation involves the random construction of a linear operator and a set of eigenvectors in Hilbert space, we can imagine that this process could be much faster than the digital simulation.
We have high hopes for the promise of quantum computation, but as Waintal points out it is very delicate process which is hard to confine to the sort of definite well defined processes (like multiplying 3 x 5) that we accustomed to compute digitally. It may be that many elements of the spectrum of a quantum proton operator may contribute to the stability of the proton, ensuring its intact survival. From an entropy point of view, it seems quite probable that an operator working in a Hilbert space of countable dimension could execute all the operations necessary to create and maintain a stable proton. Xavier Waintal (2023_12_29): The Quantum House Of Cards
Waintal also points out, near the end of his article, that conventional digital computation can be speeded up enormously by discovering symmetries in a problem. He suggests that one advantage that may come from studying quantum computation is the identification of such symmetries. Maybe a deeper understanding of quantum field theory may make it unnecessary to employ supercomputers to understand the proton.
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24.7: Physics is an empirical foundation for theology
In our evolving world old ideas, like old species, keep reproducing themselves as long as their selective environment does not change faster than they can evolve. If they cannot keep up, their population falls, leaving room for new species, new ideas. In Galileo's time, the Catholic Church used starvation, torture, and murder to maintain orthodoxy, but the environment changed. Galileo's telescopes meant that reasonable people could no longer hold that the Sun revolves around the Earth. He escaped by recantation, but the Church took a severe blow and in remains in retreat before the evolution of science. It is still taking a last stand against modern ideas like the equality of women and the idea that it should renounce autocracy and infallibility and enter the modern world. The top down authoritarians of the world are ultimately doomed. Power springs from below, which is why dictators fear democracy, people acting for their own welfare.
Isaac Newton was deeply interested in theology and he saw the magnificence of the solar system as clear evidence for the dominating power of God. He could not explain how the force of gravitation, as he understood it, could be propagated instantaneously through empty space, but felt that this was well within the power of the divinity who created the system in the first place.
Einstein solved Newton's problem, not with a field in space (as we imagine the fields in conventional quantum field theory to be), but with a the nature of space itself. Feynman investigated the idea of a quantum field theory of gravitation which required particles with spin 2 to carry the degrees of freedom necessary to model the behaviour of gravitation. From a gauge theory point of view, the gauge of gravitation is not a number representing a phase, as in the other quantum field theories, but involves the relative rotation of flat Minkowski space as indicated by the structure of a 3 + 1 dimensional differentiable manifold. Since Feynman's time the quantum field theory of gravitation has made no progress, despite the introduction of ever more complex mathematical structures. This effort seems futile, since the gravity's role in the initial singularity suggests simplicity, not complexity. Here we equate our experience of gravity with experience of divinity, everyday, not particularly mystical unless we think about it in the theological context developed here.
The emptiness of space reflects the emptiness of the classical divinity and the emptiness of the initial singularity both of which we associate with naked gravitation. Quantum mechanics creates Minkowski through the action of dynamic bosons and fermions and Minkowski space gives structure to naked gravitation. Gravitation itself may plays=a role in the giving dynamic existence to the kinematic quantum fixed points that shape the particles that shape the space that shapes the Universe along lines suggested on page 17: Gravitation and quantum theory—in the beginning
We live our day to day lives in the four dimensional spacetime imagined by Newton. We can freely move in two dimensions on horizontal surfaces, but our behaviour in the third dimension is controlled by gravitation and we have no control at all on the actual passage of time. Psychological states like sleep and wakefulness, pain and pleasure control its subjective flow, but we inevitably age and die.
Cantor saw structure in the Euclidean continuum of real numbers. From his study of the representation of the discontinuous functions through Fourier transform, he saw this structure continuing into ever more microscopic realms. Between the integers he saw the real numbers. Between the real numbers he saw an even smaller structure, and so on ad infinitum. This is his theory of derived sets. Joseph Warren Dauben (1990): Georg Cantor: His Mathematics and Philosophy of the Infinite
Then he turned the idea around, moving from the finesse of the real continuum to the count of its discrete elements, and invented the transfinite numbers. There are ℵ0 natural numbers (corresponding to isolated points), ℵ1 real numbers (points packed closer together, approximating a continuum), ℵ2 points between the real points and so on ad infinitum. He proved (formally) that this succession of numbers exists, even if we start with finite integers.
On page 21: Matter and spirit we discuss the material representation of spirit. Cantor's theorem suggests that there is no limit to the complexity of the material world, which means that there is no limit to the the representation of spirituality and the Universe. Conversely, whenever we cut down the complexity of the material world by destroying ecosystems and the species that inhabit them, we are also cutting down the planetary complexity that adds to our own spiritual expansion.
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24.8: Symmetry with respect to complexity
We began with an omnipotent structureless initial singularity and devised a story to explain its complexification. As the matter, spirit and entropy of the Universe grow the gravitational potential well in which we live deepens and the Universe expands.
Ancient stories tell us that this is the creation of a mysterious divinity beyond our understanding, but this does not make sense. Equally ancient tradition tells us that this entity is absolutely simple. There is nothing to be said about it but that it exists. This is the first theory of everything, and it seems quite easy to understand while providing infinite material for meditation.
Ancient stories also tell us that we are victims of fate and there is nothing we can do about it. Cyclones, floods, famines and wars come and go. Millions suffer and die but life goes on. The Catholic Church attributes all evil to Satan and blames us, the human victims, for offending God. Our salvation, according to the Church, was won by God condemning his own Son to a painful death as a human sacrifice on behalf of humanity.
The methods of imperialism are well know and they are, unfortunately, consistent with the nature of evolution. All life is food for life and so predation in all its forms is implicit in evolution. The difference between the evil associated with evolution and the evil arising from the satanic hatred of divinity is that the former is rational and therefore something which may be understood and possibly controlled whereas the latter is irrational and self defeating. Nations who commit genocide are destroying populations that could become citizens and add to their own power and prosperity. Their actions may be characterized as lose-lose, whereas rational action aspires to be win win.
In the evolutionary paradigm rape, pillage and predation may seem rational in the face of the alternative, passively starving to death.
Christian theodicy is based on the notion that the omnipotent and omniscient God has immediate providence over everything, and is therefore responsible for all evils. Some may see this as a proof that the God imagined by Christianity does not exist. Aquinas, Summa, I, 22, 3: Does God have immediate providence over everything?, Theodicy - Wikipedia
Providence, understood as awareness and preventative action is nevertheless the answer to evil. This idea is relatively easy to implement in controlled environments and lies at the heart of modern occupational health and safety.
The first step in this process is awareness, and the principle of symmetry with respect to complexity derived from the model of reality proposed on this site may help us to avoid some of the evils associated with evolution as the source of creation.
We begin from two points, one mathematical and the other related to natural selection.
Cantor, describing the origin of the transfinite numbers, wrote:
To every transfinite cardinal number a there is a next greater proceeding out of it according to a unitary law, and also to every unlimitedly ascending well ordered aggregate of transfinite cardinal numbers, {a}, there is a next greater proceeding out of that aggregate in a unitary way. Cantor: op. cit. page 109
This unitary law employed in Cantor's theorem points to a symmetry in the transfinite numbers. We may see a similar symmetry in quantum mechanics in Hilbert spaces. These are differentiated by the number of their dimensions but the mechanism of linear operators works independently of the size of the space, the matrices representing the operators growing with the size of the space. If we imagine, with Everett III, that there exist Hilbert spaces which can represent an infinite set of Universes, we can imagine no limit to this growth. Everett III, de Witt & Graham (1973): The Many Worlds Interpretation of Quantum Mechanics
This symmetry in Hilbert space is reflected in Minkowski space and suggests that it may always be possible, by careful study, to find a simple core in complex situations which makes them tractable to management. Finding such invariances is one of the contributions that science may make to society.
A principal problem facing most societies is imperial predation, the use, by those who possess it, of military, financial or political power to exploit or enslave people with less power. Constantine the Great executed a textbook example of this move when he coopted Christianity in the service of his empire and established the Roman Catholic Church. Constantine the Great and Christianity - Wikipedia
The Empire had no shortage of military power and the dis-establishment of the traditional pagan religions has been a financial windfall for the Empire. According to Hopkins the change of official religion from paganism to Christianity created enormous windfall profits for the Roman state. Christianity had become a power in the Empire and Constantine's mother Helena saw that it could be of great benefit to her son. Constantine organized a Council at Nicea which produced a simple and concise record of central doctrine which made catechization of converts easy and efficient. The Nicene Creed, created by bureaucrats, almost completely overlooks the central message of Christianity: love god, love your neighbour. Keith Hopkins (2001): A World Full of Gods: The Strange Triumph of Christianity, page 105
After the fall of the Roman Empire the Church carried on and eventually achieved a central role in medieval intellectual and political life. The first significant breaks in its power came with the Reformation and the Renaissance. Its power in Europe has continued to wane, but it has recovered much through its missionary activities in the wake of the colonization of the world by European imperialists. Dark Ages (historiography) - Wikipedia
Although is is the most powerful religion in terms of membership, wealth and connection to military and intellectual power, there are other major religions of comparable power which, like the Church, have imperialist tendencies. One can see that the principal source of war in the present world is theocracy and there is an urgent need for theological reform along the lines suggested by modern science, human rights and democratic politics.
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Notes and references
Further readingBooks
Auyang (1995), Sunny Y., How is Quantum Field Theory Possible?, Oxford University Press 1995 Jacket: 'Quantum field theory (QFT) combines quantum mechanics with Einstein's special theory of relativity and underlies elementary particle physics. This book presents a philosophical analysis of QFT. It is the first treatise in which the philosophies of space-time, quantum phenomena and particle interactions are encompassed in a unified framework.'
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Cantor (1897, 1955), Georg, Contributions to the Founding of the Theory of Transfinite Numbers (Translated, with Introduction and Notes by Philip E B Jourdain), Dover 1895, 1897, 1955 Jacket: 'One of the greatest mathematical classics of all time, this work established a new field of mathematics which was to be of incalculable importance in topology, number theory, analysis, theory of functions, etc, as well as the entire field of modern logic.'
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Darwin (1875, 1998), Charles, and Harriet Ritvo (Introduction), The Variation of Animals and Plants Under Domestication (Foundations of Natural History), Johns Hopkins University Press 1875, 1998 ' "The Variation, with its thousands of hard-won observations of the facts of variation in domesticated species, is a frustrating, but worthwhile read, for it reveals the Darwin we rarely see -- the embattled Darwin, struggling to keep his project on the road. Sometimes he seems on the verge of being overwhelmed by the problems he is dealing with, but then a curious fact of natural history will engage him (the webbing between water gun-dogs' toes, the absurdly short beak of the pouter pigeon) and his determination to make sense of it rekindles. As he disarmingly declares, 'the whole subject of inheritance is wonderful.'.
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Dauben (1990), Joseph Warren, Georg Cantor: His Mathematics and Philosophy of the Infinite, Princeton University Press 1990 Jacket: 'One of the greatest revolutions in mathematics occurred when Georg Cantor (1843-1918) promulgated his theory of transfinite sets. . . . Set theory has been widely adopted in mathematics and philosophy, but the controversy surrounding it at the turn of the century remains of great interest. Cantor's own faith in his theory was partly theological. His religious beliefs led him to expect paradox in any concept of the infinite, and he always retained his belief in the utter veracity of transfinite set theory. Later in his life, he was troubled by attacks of severe depression. Dauben shows that these played an integral part in his understanding and defense of set theory.'
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Everett III (1973), Hugh, and Bryce S Dewitt, Neill Graham (editors), The Many Worlds Interpretation of Quantum Mechanics, Princeton University Press 1973 Jacket: 'A novel interpretation of quantum mechanics, first proposed in brief form by Hugh Everett in 1957, forms the nucleus around which this book has developed. The volume contains Dr Everett's short paper from 1957, "'Relative State' formulation of quantum mechanics" and a far longer exposition of his interpretation entitled "The Theory of the Universal Wave Function" never before published. In addition other papers by Wheeler, DeWitt, Graham, Cooper and van Vechten provide further discussion of the same theme. Together they constitute virtually the entire world output of scholarly commentary on the Everett interpretation.'
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Farmelo (2009), Graham, The Strangest Man: The Hidden Life of Paul Dirac, Mystic of the Atom, Basic Books 2009 Jacket: 'Paul Dirac was among the greatest scientific geniuses of the modern age. One of the discoverers of quantum mechanics, the most revolutionary theory of the last century, his contributions had a unique insight, eloquence, clarity and mathematical power. His prediction of antimatter was one of the greatest triumphs in the history of physics. One of Einstein's most admired colleagues, Dirac was in 1933 the youngest theoretician ever to win a Nobel Prize in physics. . . . Based on previously undiscovered archives, The Strangest Man reveals the many facets of Dirac's brilliantly original mind. The Strangest Man also depicts a spectacularly exciting era in scientific discovery.'
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Fortun (1998), Mike, and Herbert J Bernstein, Muddling Through: Pursuing Science and Truths in the Twenty-First Century, Counterpoint 1998 Jacket: ' Messy. Clumsy. Volatile. Exciting. These words are not often associated with the science, which for most people still connote exactitude, elegance, reliability and a rather plodding certainty. But the real story is something quite different. The sciences are less about the ability to know and to control than they are about the unleashing of new forces, new capacities for changing the world. The sciences as practised exist not in some pristine world of "objectivity," but in what Mike Fortnum and Herbert Bernstein call "the Muddled Middle".
This book explores the way science makes sense of the world and how the world makes sense of science. It is also about politics and culture—how these forces shape the sciences and are shaped by them in return.'
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Galilei (1610, 1957), Galileo, and Stillman Drake (translator), Discoveries and Opinions of Galileo: Including the Starry Messenger (1610 Letter to the Grand Duchess Christina), Doubleday Anchor 1957 Amazon: 'Although the introductory sections are a bit dated, this book contains some of the best translations available of Galileo's works in English. It includes a broad range of his theories (both those we recognize as "correct" and those in which he was "in error"). Both types indicate his creativity. The reproductions of his sketches of the moons of Jupiter (in "The Starry Messenger") are accurate enough to match to modern computer programs which show the positions of the moons for any date in history. The appendix with a chronological summary of Galileo's life is very useful in placing the readings in context.' A Reader.
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Goddard (1998), Peter , and Stephen Hawking, Abraham Pais, Maurice Jacob, David Olive, and Michael Atiyah, Paul Dirac, The Man and His Work, Cambridge University Press 1998 Jacket: Paul Adrien Maurice Dirac was one of the founders of quantum theory and the aithor of many of its most important subsequent developments. He is numbered alongside Newton, Maxwell, Einstein and Rutherford as one of the greatest physicists of all time.
This volume contains four lectures celebrating Dirac's life and work and the text of an address given by Stephen Hawking, which were given on 13 November 1995 on the occasion of the dedication of a plaque to him in Westminster Abbey. In the first lecture, Abraham Pais describes from personal knowledge Dirac's character and his approach to his work. In the second lecture, Maurice Jacob explains not only how and why Dirac was led to introduce the concept of antimatter, but also its central role in modern particle physics and cosmology. In the third lecture, David Olive gives an account of Dirac's work on magnetic monopoles and shows how it has had a profound influence in the development of fundamental physics down to the present day. In the fourth lecture, Sir Michael Atiyah explains the widespread significance of the Dirac equation in mathematics, its roots in algebra and its implications for geometry and topology.'
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Hopkins (2001), Keith, A World Full of Gods: The Strange Triumph of Christianity, Penguin Random House 2001 ' In this provocative, irresistibly entertaining book, Keith Hopkins takes readers back in time to explore the roots of Christianity in ancient Rome. Combining exacting scholarship with dazzling invention, Hopkins challenges our perceptions about religion, the historical Jesus, and the way history is written. He puts us in touch with what he calls “empathetic wonder”—imagining what Romans, pagans, Jews, and Christians thought, felt, experienced, and believed-by employing a series of engaging literary devices. These include a TV drama about the Dead Sea Scrolls; the first-person testimony of a pair of time-travelers to Pompeii; a meditation on Jesus’ apocryphal twin brother; and an unusual letter on God, demons, and angels.'
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Howard (2000), Don, and John Steichel (editor), Einstein: The Formative Years, 1879-1909 (Einstein Studies volume 8), Birkhauser 2000 ' "What was Einstein like for the first thirty years of his life? Who were the personalities who guided him? What did he read? This book, which hopes to shed light on these questions, is a sequence of academic articles written by Einstein specialists for the Birkhäuser Einstein Studies series. . . .The [book] is remarkably readable and informative. . . .Indispensable for Einstein disciples, the book is also accessible to the general reader. The presentation is excellent and the editing conducted to a high standard. . . .Extensive references are given after each essay and an index of names is provided." '
--The Mathematical Gazette
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Nielsen (2016), Michael A., and Isaac L Chuang, Quantum Computation and Quantum Information, Cambridge University Press 2016 Review: A rigorous, comprehensive text on quantum information is timely. The study of quantum information and computation represents a particularly direct route to understanding quantum mechanics. Unlike the traditional route to quantum mechanics via Schroedinger's equation and the hydrogen atom, the study of quantum information requires no calculus, merely a knowledge of complex numbers and matrix multiplication. In addition, quantum information processing gives direct access to the traditionally advanced topics of measurement of quantum systems and decoherence.' Seth Lloyd, Department of Quantum Mechanical Engineering, MIT, Nature 6876: vol 416 page 19, 7 March 2002.
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Popper (1972), Karl Raimund, Conjectures and Refutations: The Growth of Scientific Knowledge, Routledge and Kegan Paul 1972 Preface: 'The way in which knowledge progresses, and expecially our scientific knowledge, is by unjustified (and unjustifiable) anticipations, by guesses, by tentative solutions to our problems, by conjectures. These conjectures are controlled by criticism; that is, by attempted refutations, which include severely critical tests.' [p viii]
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Streater (2000), Raymond F, and Arthur S Wightman, PCT, Spin, Statistics and All That, Princeton University Press 2000 Amazon product description: 'PCT, Spin and Statistics, and All That is the classic summary of and introduction to the achievements of Axiomatic Quantum Field Theory. This theory gives precise mathematical responses to questions like: What is a quantized field? What are the physically indispensable attributes of a quantized field? Furthermore, Axiomatic Field Theory shows that a number of physically important predictions of quantum field theory are mathematical consequences of the axioms. Here Raymond Streater and Arthur Wightman treat only results that can be rigorously proved, and these are presented in an elegant style that makes them available to a broad range of physics and theoretical mathematics.'
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Wilczek (2008), Frank, The Lightness of Being: Mass, Ether, and the Unification of Forces, Basic Books 2008 ' In this excursion to the outer limits of particle physics, Wilczek explores what quarks and gluons, which compose protons and neutrons, reveal about the manifestation of mass and gravity. A corecipient of the 2004 Nobel Prize in Physics, Wilczek knows what he’s writing about; the question is, will general science readers? Happily, they know what the strong interaction is (the forces that bind the nucleus), and in Wilczek, they have a jovial guide who adheres to trade publishing’s belief that a successful physics title will not include too many equations. Despite this injunction (against which he lightly protests), Wilczek delivers an approachable verbal picture of what quarks and gluons are doing inside a proton that gives rise to mass and, hence, gravity. Casting the light-speed lives of quarks against “the Grid,” Wilczek’s term for the vacuum that theoretically seethes with quantum activity, Wilczek exudes a contagious excitement for discovery. A near-obligatory acquisition for circulating physics collections.' --Gilbert Taylor
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Zee (2010), Anthony, Quantum Field Theory in a Nutshell, Princeton University Press 2010 ' Since it was first published, Quantum Field Theory in a Nutshell has quickly established itself as the most accessible and comprehensive introduction to this profound and deeply fascinating area of theoretical physics. Now in this fully revised and expanded edition, A. Zee covers the latest advances while providing a solid conceptual foundation for students to build on, making this the most up-to-date and modern textbook on quantum field theory available. This expanded edition features several additional chapters, as well as an entirely new section describing recent developments in quantum field theory such as gravitational waves, the helicity spinor formalism, on-shell gluon scattering, recursion relations for amplitudes with complex momenta, and the hidden connection between Yang-Mills theory and Einstein gravity. Zee also provides added exercises, explanations, and examples, as well as detailed appendices, solutions to selected exercises, and suggestions for further reading.'
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Links
Aether (classical element) - Wikipedia, Aether (classical element) - Wikipedia, the free encyclopedia, 'According to ancient and medieval science aether (Greek αἰθήρ aithēr), also spelled æther or ether, is the material that fills the region of the universe above the terrestrial sphere.' back |
Albert Einstein (1905c), On a heuristic point of view concerning the production and transformation of light, ' The wave theory of light, which operates with continuous spatial functions, has proved itself splendidly in describing purely optical phenomena and will probably never be replaced by another theory. One should keep in mind, however, that optical observations apply to time averages and not to momentary values, and it is conceivable that despite the complete confirmation of the theories of diffraction, reflection, refraction, dispersion, etc., by experiment, the theory of light, which operates with continuous spatial functions, may lead to contradictions with experience when it is applied to the phenomena of production and transformation of light.
Indeed, it seems to me that the observations regarding "black-body" light, and other groups of phenomena associated with the production or conversion of light can be understood better if one assumes that the energy of light is discontinuously distributed in space.' back |
Albert Einstein (1905c), On a heuristic point of view concerning the production and transformation of light, ' In particular, black body radiation, photoluminescence, generation of cathode rays from ultraviolet light and other phenomena associated with the generation and transformation of light seem better modeled by assuming that the energy of light is distributed discontinuously in space. According to this picture, the energy of a light wave emitted from a point source is not spread continuously over ever larger volumes, but consists of a finite number of energy quanta that are spatially localized at points of space, move without dividing and are absorbed or generated only as a whole.
Subsequently, I wish to explain the reasoning and supporting evidence that led me to this picture of light, in the hope that some researchers may find it useful for their experiments.' back |
Albert Einstein (1915), The Field Equations of Gravitation, ' In two recently published papers I have shown how to obtain field equations of gravitation that comply with the postulate of general relativity, i.e., which in their general formulation are covariant under arbitrary substitutions of space-time variables. . . . With this, we have finally completed the general theory of relativity as a logical structure. The postulate of relativity in its most general formulation (which makes space-time coordinates into physically meaningless parameters) leads with compelling necessity to a very specific theory of gravitation that also explains the movement of the perihelion of Mercury. However, the postulate of general relativity cannot reveal to us anything new and different about the essence of the various processes in nature than what the special theory of relativity taught us already.'
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Albert Einstein (1920), Ether and the Theory of Relativity, ' How does it come about that alongside of the idea of ponderable matter, which is derived by abstraction from everyday life, the physicists set the idea of the existence of another kind of matter, the ether? The explanation is probably to be sought in those phenomena which have given rise to the theory of action at a distance, and in the properties of light which have led to the undulatory theory. Let us devote a little while to the consideration of these two subjects. . . . ..
Recapitulating, we may say that according to the general theory of relativity space is endowed with physical qualities; in this sense, therefore, there exists an ether. According to the general theory of relativity space without ether is unthinkable; for in such space there not only would be no propagation of light, but also no possibility of existence for standards of space and time (measuring-rods and clocks), nor therefore any space-time intervals in the physical sense. But this ether may not be thought of as endowed with the quality characteristic of ponderable media, as consisting of parts which may be tracked through time. The idea of motion may not be applied to it.' back |
Aquinas, Summa, I, 22, 3, Does God have immediate providence over everything?, ' I answer that, Two things belong to providence—namely, the type of the order of things foreordained towards an end; and the execution of this order, which is called government. As regards the first of these, God has immediate providence over everything, because He has in His intellect the types of everything, even the smallest; and whatsoever causes He assigns to certain effects, He gives them the power to produce those effects. Whence it must be that He has beforehand the type of those effects in His mind. As to the second, there are certain intermediaries of God's providence; for He governs things inferior by superior, not on account of any defect in His power, but by reason of the abundance of His goodness; so that the dignity of causality is imparted even to creatures.' back |
Augustus - Wikipedia, Augustus - Wikipedia, the free encyclopedia, ' Gaius Julius Caesar Augustus (born Gaius Octavius; 23 September 63 BC – 19 August AD 14), also known as Octavian (Latin: Octavianus), was the founder of the Roman Empire. He reigned as the first Roman emperor from 27 BC until his death in AD 14. The reign of Augustus initiated an imperial cult, as well as an era associated with imperial peace (the Pax Romana or ,Pax Augusta) in which the Roman world was largely free of armed conflict (aside from expansionary wars and the Year of the Four Emperors, the latter of which occurring after Augustus' reign).' back |
Cantor's theorem - Wikipedia, Cantor's theorem - Wikipedia, the free encyclopedia, ' In mathematical set theory, Cantor's theorem is a fundamental result which states that, for any set A , the set of all subsets of A, the power set of A, has a strictly greater cardinality than A itself.
For finite sets, Cantor's theorem can be seen to be true by simple enumeration of the number of subsets. Counting the empty set as a subset, a set with n elements has a total of n 2 subsets, and the theorem holds because n2 > n for all non-negative integers.
Much more significant is Cantor's discovery of an argument that is applicable to any set, and shows that the theorem holds for infinite sets also.' back |
Cardinal number - Wikipedia, Cardinal number - Wikipedia, the free encyclopedia, 'In mathematics, cardinal numbers, or cardinals for short, are a generalization of the natural numbers used to measure the cardinality (size) of sets. The cardinality of a finite set is a natural number: the number of elements in the set. The transfinite cardinal numbers describe the sizes of infinite sets.' back |
Cardinality of the continuum - Wikipedia, Cardinality of the continuum - Wikipedia, the free encyclopedia, 'In mathematics, the cardinality of the continuum (sometimes also called the power of the continuum) is the cardinal number of the set of real numbers R (sometimes called the continuum). This cardinal number is often denoted by c, so c = R.' back |
Claude Shannon (1949), Communication in the Presence of Noise, 'A method is developed for representing any communication system geometrically. Messages and the corresponding signals are points in two “function spaces,” and the modulation process is a mapping of one space into the other. Using this representation, a number of results in communication theory are deduced concerning expansion and compression of bandwidth and the threshold effect. Formulas are found for the maximum rate of transmission of binary digits over a system when the signal is perturbed by various types of noise. Some of the properties of “ideal” systems which transmit at this maximum rate are discussed. The equivalent number of binary digits per second for certain information sources is calculated.' [C. E. Shannon , “Communication in the presence of noise,” Proc. IRE,
vol. 37, pp. 10–21, Jan. 1949.] back |
Constantine the Great and Christianity - Wikipedia, Constantine the Great and Christianity - Wikipedia, the free encyclopedia, ' During the reign of the Roman Emperor Constantine the Great (AD 306–337), Christianity began to transition to the dominant religion of the Roman Empire. Historians remain uncertain about Constantine's reasons for favoring Christianity, and theologians and historians have often argued about which form of early Christianity he subscribed to. . . . Constantine's decision to cease the persecution of Christians in the Roman Empire was a turning point for early Christianity, sometimes referred to as the Triumph of the Church, the Peace of the Church or the Constantinian shift. In 313, Constantine and Licinius issued the Edict of Milan decriminalizing Christian worship. The emperor became a great patron of the Church and set a precedent for the position of the Christian emperor within the Church and raised the notions of orthodoxy, Christendom, ecumenical councils, and the state church of the Roman Empire declared by edict in 380. He is revered as a saint and is apostolos in the Eastern Orthodox Church, Oriental Orthodox Church, and various Eastern Catholic Churches for his example as a "Christian monarch”.' back |
Cosmological constant - Wikipedia, Cosmological constant - Wikipedia, the free encyclopedia, 'In physical cosmology, the cosmological constant (usually denoted by the Greek capital letter lambda) was proposed by Albert Einstein as a modification of his original theory of general relativity to achieve a stationary universe. Einstein abandoned the concept after the observation of the Hubble redshift indicated that the universe might not be stationary, as he had based his theory off the idea that the universe is unchanging. However, the discovery of cosmic acceleration in the 1990s has renewed interest in a cosmological constant.' back |
Cosmological constant problem - Wikipedia, Cosmological constant problem - Wikipedia, the free encyclopedia, ' In cosmology, the cosmological constant problem or vacuum catastrophe is the disagreement between the observed values of vacuum energy density (the small value of the cosmological constant) and theoretical large value of zero-point energy suggested by quantum field theory.
Depending on the Planck energy cutoff and other factors, the discrepancy is as high as 120 orders of magnitude, a state of affairs described by physicists as "the largest discrepancy between theory and experiment in all of science" and "the worst theoretical prediction in the history of physics".' back |
Dark Ages (historiography) - Wikipedia, Dark Ages (historiography) - Wikipedia, the free encyclopedia, ' The Dark Ages is a term for the Early Middle Ages (c. 5th–10th centuries), or occasionally the entire Middle Ages (c. 5th–15th centuries), in Western Europe after the fall of the Western Roman Empire, which characterises it as marked by economic, intellectual, and cultural decline.
The concept of a "Dark Age" as a historiographical periodization originated in the 1330s with the Italian scholar Petrarch, who regarded the post-Roman centuries as "dark" compared to the "light" of classical antiquity. . . .
Others, however, have used the term to denote the relative scarcity of records regarding at least the early part of the Middle Ages.' back |
David J. Gross (2004), Nobel lecture: The Discovery of Asymptotic Freedom and the Emergence of QCD, ' The emergence of QCD is a wonderful example of the evolution from farce to triumph. During a very short period, a transition occurred from experimental discovery and theoretical confusion to theoretical triumph and experimental confirmation. In this Nobel lecture I shall describe the turn of events that led to the discovery of asymptotic freedom, which in turn led to the formulation of QCD, the final element of the remarkably comprehensive theory of elementary particle physics – the Standard Model. I shall then briefly describe the experimental tests of the theory and the implications of asymptotic freedom.' back |
Deep inelastic scattering - Wikipedia, Deep inelastic scattering - Wikipedia, the free encyclopedia, ' Deep inelastic scattering is the name given to a process used to probe the insides of hadrons (particularly the baryons, such as protons and neutrons), using electrons, muons and neutrinos. It provided the first convincing evidence of the reality of quarks, which up until that point had been considered by many to be a purely mathematical phenomenon. . . .
Henry Way Kendall, Jerome Isaac Friedman and Richard E. Taylor were joint recipients of the Nobel Prize of 1990 "for their pioneering investigations concerning deep inelastic scattering of electrons on protons and bound neutrons, which have been of essential importance for the development of the quark model in particle physics".' back |
Eigenvalues and eigenvectors - Wikipedia, Eigenvalues and eigenvectors - Wikipedia, the free encyclopedia, ' In linear algebra, an eigenvector or characteristic vector of a linear transformation is a nonzero vector that changes at most by a scalar factor when that linear transformation is applied to it. The corresponding eigenvalue, often denoted by λ, is the factor by which the eigenvector is scaled.
Geometrically, an eigenvector, corresponding to a real nonzero eigenvalue, points in a direction in which it is stretched by the transformation and the eigenvalue is the factor by which it is stretched. If the eigenvalue is negative, the direction is reversed. Loosely speaking, in a multidimensional vector space, the eigenvector is not rotated.' back |
Electroweak interaction - Wikipedia, Electroweak interaction - Wikipedia, the free encyclopedia, ' In particle physics, the electroweak interaction or electroweak force is the unified description of two of the four known fundamental interactions of nature: electromagnetism and the weak interaction. Although these two forces appear very different at everyday low energies, the theory models them as two different aspects of the same force. Above the unification energy, on the order of 246 GeV, they would merge into a single force.' back |
Entropy (information theory) - Wikipedia, Entropy (information theory) - Wikipedia, the free encyclopedia, 'In information theory, entropy is a measure of the uncertainty associated with a random variable. In this context, the term usually refers to the Shannon entropy, which quantifies the expected value of the information contained in a message, usually in units such as bits. In this context, a 'message' means a specific realization of the random variable.
Equivalently, the Shannon entropy is a measure of the average information content one is missing when one does not know the value of the random variable. The concept was introduced by Claude E. Shannon in his 1948 paper "A Mathematical Theory of Communication".' back |
Feynman, Leighton and Sands FLP II_02, Chapter 2: Differential Calculus of Vector Fields, ' Ideas such as the field lines, capacitance, resistance, and inductance are, for such purposes, very useful. So we will spend much of our time analyzing them. In this way we will get a feel as to what should happen in different electromagnetic situations. On the other hand, none of the heuristic models, such as field lines, is really adequate and accurate for all situations. There is only one precise way of presenting the laws, and that is by means of differential equations. They have the advantage of being fundamental and, so far as we know, precise. If you have learned the differential equations you can always go back to them. There is nothing to unlearn.' back |
Frank Wilczek (2004), Nobel lecture: Asymptotic Freedom: from Paradox to Paradigm, ' Frank Wilczek held his Nobel lecture December 8, 2004, at Aula Magna, Stockholm University. He was presented by Professor Sune Svanberg, Chairman of the Nobel Committee for Physics.
Summary: The idea that Quarks that are born free are confined and can’t be pulled apart was once considered a paradox. The emerging theory for strong interactions, Quantum Chromo Dynamics (QCD) predicts the existence of gluons, which together with quarks can be seen indirectly as jets from hard scattering reactions between particles. Quantum Chromo Dynamics predicts that the forces between quarks are feeble for small separations but are powerful far away, which explains confinement. Many experiments have confirmed this property of the strong interaction. '
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Function (mathematics) - Wikipedia, Function (mathematics) - Wikipedia, the free encyclopedia, ' The mathematical concept of a function expresses dependence between two quantities, one of which is given (the independent variable, argument of the function, or its "input") and the other produced (the dependent variable, value of the function, or "output"). A function associates a single output with every input element drawn from a fixed set, such as the real numbers.' back |
Georg Cantor - Wikipedia, Georg Cantor - Wikipedia, the free encyclopedia, Georg Ferdinand Ludwig Philipp Cantor (March 3 [O.S. February 19] 1845 – January 6, 1918) was a German mathematician, born in Russia. He is best known as the creator of set theory, which has become a fundamental theory in mathematics. Cantor established the importance of one-to-one correspondence between sets, defined infinite and well-ordered sets, and proved that the real numbers are "more numerous" than the natural numbers. In fact, Cantor's theorem implies the existence of an "infinity of infinities". He defined the cardinal and ordinal numbers and their arithmetic. Cantor's work is of great philosophical interest, a fact of which he was well aware of.' back |
Gluon - Wikipedia, Gluon - Wikipedia, the free encyclopedia, ' A gluon (/ˈɡluːɒn/) is an elementary particle that acts as the exchange particle (or gauge boson) for the strong force between quarks. It is analogous to the exchange of photons in the electromagnetic force between two charged particles.[6] In layman's terms, they "glue" quarks together, forming hadrons such as protons and neutrons.
In technical terms, gluons are vector gauge bosons that mediate strong interactions of quarks in quantum chromodynamics (QCD). Gluons themselves carry the color charge of the strong interaction. This is unlike the photon, which mediates the electromagnetic interaction but lacks an electric charge. Gluons therefore participate in the strong interaction in addition to mediating it, making QCD significantly harder to analyze than quantum electrodynamics (QED). ' back |
Gödel's incompleteness theorems - Wikipedia, Gödel's incompleteness theorems - Wikipedia, the free encyclopedia, ' Gödel's incompleteness theorems are two theorems of mathematical logic that establish inherent limitations of all but the most trivial axiomatic systems capable of doing arithmetic. The theorems, proven by Kurt Gödel in 1931, are important both in mathematical logic and in the philosophy of mathematics. The two results are widely, but not universally, interpreted as showing that Hilbert's program to find a complete and consistent set of axioms for all mathematics is impossible, giving a negative answer to Hilbert's second problem.
The first incompleteness theorem states that no consistent system of axioms whose theorems can be listed by an "effective procedure" (i.e., any sort of algorithm) is capable of proving all truths about the relations of the natural numbers (arithmetic). For any such system, there will always be statements about the natural numbers that are true, but that are unprovable within the system. The second incompleteness theorem, an extension of the first, shows that such a system cannot demonstrate its own consistency.' back |
Hadron - Wikipedia, Hadron - Wikipedia, the free encyclopedia, In particle physics, a hadron is a composite subatomic particle made of two or more quarks held together by the strong interaction. They are analogous to molecules that are held together by the electric force. Most of the mass of ordinary matter comes from two hadrons: the proton and the neutron, while most of the mass of the protons and neutrons is in turn due to the binding energy of their constituent quarks, due to the strong force.' back |
Hilbert's program - Wikipedia, Hilbert's program - Wikipedia, the free encyclopedia, ' In mathematics, Hilbert's program, formulated by German mathematician David Hilbert, was a proposed solution to the foundational crisis of mathematics, when early attempts to clarify the foundations of mathematics were found to suffer from paradoxes and inconsistencies. As a solution, Hilbert proposed to ground all existing theories to a finite, complete set of axioms, and provide a proof that these axioms were consistent. Hilbert proposed that the consistency of more complicated systems, such as real analysis, could be proven in terms of simpler systems. Ultimately, the consistency of all of mathematics could be reduced to basic arithmetic.' back |
Hugh Everett III (1957), "Relative State" Formulation of Quantum Mechanics, ' 1. Introduction
The task of quantizing general relativity raises serious questions about the meaning of the present formulation and interpretation of quantum mechanics when applied to so fundamental a structure as the space-time geometry itself. This paper seeks to clarify the foundations of quantum mechanics. It presents a reformulation of quantum theory in a form believed suitable for application
to general relativity. . . .
The relationship of this new formulation to the older formulation is therefore that of a metatheory to a theory, that is, it is an underlying theory in which the nature and consistency, as well as the realm of applicability, of the older theory can be investigated and clarified.' back |
John von Neumann (2014), Mathematical Foundations of Quantum Mechanics, ' Mathematical Foundations of Quantum Mechanics by John von Neumann translated from the German by Robert T. Beyer (New Edition) edited by Nicholas A. Wheeler. Princeton UP Princeton & Oxford.
Preface: ' This book is the realization of my long-held intention to someday use the resources of TEX to produce a more easily read version of Robert T. Beyer’s authorized English translation (Princeton University Press, 1955) of John von Neumann’s classic Mathematische Grundlagen der Quantenmechanik (Springer, 1932).'This content downloaded from 129.127.145.240 on Sat, 30 May 2020 22:38:31 UTC
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Kashgarian, Lusuegro & Siddique (2024), The Warfare State: How Funding for Militarism Compromises Our Welfare, ' In FY 2023, out of a $1.8 trillion federal discretionary budget, $1.1 trillion— or 62% — was for militarized programs that use violence or the threat of violence or imprisonment, including war and weapons, law enforcemen and mass incarceration, and detention and deportation. . . ..
The U.S. spent $16 on the military and war for every $1 that was spent on diplomacy and humanitarian foreign aid. The vast majority of militarized pending was for weapons, war and the Pentagon, at $920 billion. Only 56 billion was spent for international affairs, diplomacy, and humanitarian foreign aid. . . . .
The U.S. federal budget allocated twice as much for federal law enforcement, which includes federal prisons, the FBI and other law enforcement agencies $31 billion), as for child care and early childhood education programs ($15 billion).'
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Kirchoff's law of thermal radiation - Wikipedia, Kirchoff's law of thermal radiation - Wikipedia, the free encyclopedia, 'Kirchhoff's law states that:
For a body of any arbitrary material, emitting and absorbing thermal electromagnetic radiation at every wavelength in thermodynamic equilibrium, the ratio of its emissive power to its dimensionless coefficient of absorption is equal to a universal function only of radiative wavelength and temperature, the perfect black-body emissive power. back |
Lamb shift - Wikipedia, Lamb shift - Wikipedia, the free encyclopedia, 'In physics, the Lamb shift, named after Willis Lamb (1913–2008), is a difference in energy between two energy levels 2S½ and 2P½ (in term symbol notation) of the hydrogen atom which was not predicted by the Dirac equation, according to which these states should have the same energy.
Interaction between vacuum energy fluctuations and the hydrogen electron in these different orbitals is the cause of the Lamb Shift, as was shown subsequent to its discovery.' back |
Light cone - Wikipedia, Light cone - Wikipedia, the free encyclopedia, 'A Light cone is the path that a flash of light, emanating from a single event E (localized to a single point in space and a single moment in time) and traveling in all directions, would take through spacetime. Imagine the light confined to a two-dimensional plane, the light from the flash spreads out in a circle after the event E occurs—and when graphed the growing circle with the vertical axis of the graph representing time, the result is a cone, known as the future light cone (some animated diagrams depicting this concept can be seen here.) ' back |
Map (mathematics) - Wikipedia, Map (mathematics) - Wikipedia, the free encyclopedia, ' n mathematics, a map or mapping is a function in its general sense. These terms may have originated as from the process of making a geographical map: mapping the Earth surface to a sheet of paper.
The term map may be used to distinguish some special types of functions, such as homomorphisms. For example, a linear map is a homomorphism of vector spaces, while the term linear function may have this meaning or it may mean a linear polynomial. In category theory, a map may refer to a morphism. The term transformation can be used interchangeably, but transformation often refers to a function from a set to itself. There are also a few less common uses in logic and graph theory. ' back |
Martinus J G Veltman, Nobel Lecture 1999: From weak interactions to gravitation, ' This lecture is about my contribution to the renormalizability of gauge theories. There is of course no perfectly clear separation between my contributions and those of my co-laureate 't Hooft, but I will limit mysef to some brief comments on those publications that carry only his name. An extensive review on the subject including detailed references to contemporary work can be found elsewhere.
As is well known, the work on renormalizability of gauge theories caused a complete change in the landscape of particle physics.' back |
Mathematical formulation of the standard model - Wikipedia, Mathematical formulation of the standard model - Wikipedia, the free encyclopedia, ' This article describes the mathematics of the Standard Model of particle physics, a gauge quantum field theory containing the internal symmetries of the unitary product group SU(3) × SU(2) × U(1). The theory is commonly viewed as describing the fundamental set of particles – the leptons, quarks, gauge bosons and the Higgs boson.
The Standard Model is renormalizable and mathematically self-consistent, however despite having huge and continued successes in providing experimental predictions it does leave some unexplained phenomena. In particular, although the physics of special relativity is incorporated, general relativity is not, and the Standard Model will fail at energies or distances where the graviton is expected to emerge. Therefore, in a modern field theory context, it is seen as an effective field theory.' back |
Meinard Kuhlmann (Stanford Encyclopedia of Philosophy), Quantum Field Theory, ' Quantum Field Theory (QFT) is the mathematical and conceptual framework for contemporary elementary particle physics. In a rather informal sense QFT is the extension of quantum mechanics (QM), dealing with particles, over to fields, i.e. systems with an infinite number of degrees of freedom. (See the entry on quantum mechanics.) In the last few years QFT has become a more widely discussed topic in philosophy of science, with questions ranging from methodology and semantics to ontology. QFT taken seriously in its metaphysical implications seems to give a picture of the world which is at variance with central classical conceptions of particles and fields, and even with some features of QM.' back |
Nuclear fission - Wikipedia, Nuclear fission - Wikipedia, the free encyclopedia, ' Nuclear fission of heavy elements was discovered on December 17, 1938 by German Otto Hahn and his assistant Fritz Strassmann at the suggestion of Austrian-Swedish physicist Lise Meitner who explained it theoretically in January 1939 along with her nephew Otto Robert Frisch. Frisch named the process by analogy with biological fission of living cells. For heavy nuclides, it is an exothermic reaction which can release large amounts of energy both as electromagnetic radiation and as kinetic energy of the fragments (heating the bulk material where fission takes place).' back |
Ordinal number - Wikipedia, Ordinal number - Wikipedia, the free encyclopedia, 'Whereas the notion of cardinal number is associated with a set with no particular structure on it, the ordinals are intimately linked with the special kind of sets that are called well-ordered (so intimately linked, in fact, that some mathematicians make no distinction between the two concepts). A well-ordered set is a totally ordered set (given any two elements one defines a smaller and a larger one in a coherent way) in which there is no infinite decreasing sequence (however, there may be infinite increasing sequences); equivalently, every non-empty subset of the set has a least element. Ordinals may be used to label the elements of any given well-ordered set (the smallest element being labelled 0, the one after that 1, the next one 2, "and so on") and to measure the "length" of the whole set by the least ordinal that is not a label for an element of the set. This "length" is called the order type of the set.' back |
Øystein Linnebo (Stanford Encyclopedia of Philosophy), Platonism in the Philosophy of Mathematics, ' Platonism about mathematics (or mathematical platonism) is the metaphysical view that there are abstract mathematical objects whose existence is independent of us and our language, thought, and practices. Just as electrons and planets exist independently of us, so do numbers and sets. And just as statements about electrons and planets are made true or false by the objects with which they are concerned and these objects’ perfectly objective properties, so are statements about numbers and sets. Mathematical truths are therefore discovered, not invented.' back |
Paul Dirac - Wikipedia, Paul Dirac - Wikipedia, the free encyclopedia, ' Paul Adrien Maurice Dirac OM FRS (8 August 1902 – 20 October 1984) was an English mathematical and theoretical physicist who is considered to be one of the founders of quantum mechanics and quantum electrodynamics. He is credited with laying the foundations of quantum field theory. . . ..
Dirac made fundamental contributions to the early development of both quantum mechanics and quantum electrodynamics, coining the latter term. Among other discoveries, he formulated the Dirac equation in 1928, which describes the behaviour of fermions and predicted the existence of antimatter, and is considered one of the most important equations in physics, with it being considered by some to be the "real seed of modern physics". back |
Photoelectric effect - Wikipedia, Photoelectric effect - Wikipedia, the free encyclopedia, 'The photoelectric effect is the emission of electrons when electromagnetic radiation, such as light, hits a material. Electrons emitted in this manner are called photoelectrons. . . .
The experimental results disagree with classical electromagnetism, which predicts that continuous light waves transfer energy to electrons, which would then be emitted when they accumulate enough energy. An alteration in the intensity of light would theoretically change the kinetic energy of the emitted electrons, with sufficiently dim light resulting in a delayed emission. The experimental results instead show that electrons are dislodged only when the light exceeds a certain frequency—regardless of the light's intensity or duration of exposure.' back |
Planck's Law - Wikipedia, Planck's Law - Wikipedia, the free encyclopedia, ' In physics, Planck's law describes the spectral radiance of electromagnetic radiation at all wavelengths from a black body at temperature T. As a function of frequency ν. back |
Plant reproduction - Wikipedia, Plant reproduction - Wikipedia, the free encyclopedia, ' Plant reproduction is the production of new offspring in plants, which can be accomplished by sexual or asexual reproduction. Sexual reproduction produces offspring by the fusion of gametes, resulting in offspring genetically different from either parent. Asexual reproduction produces new individuals without the fusion of gametes, resulting in clonal plants that are genetically identical to the parent plant and each other, unless mutations occur.' back |
Plant reproductive morphology - Wikipedia, Plant reproductive morphology - Wikipedia, the free encyclopedia, ' Flowering plants: Basic flower morphology:
The flower is the characteristic structure concerned with sexual reproduction in flowering plants (angiosperms). Flowers vary enormously in their structure (morphology). A perfect flower, like that of Ranunculus glaberrimus shown in the figure, has a calyx of outer sepals and a corolla of inner petals and both male and female sex organs. The sepals and petals together form the perianth. Next inwards there are numerous stamens, which produce pollen grains, each containing a microscopic male gametophyte. Stamens may be called the "male" parts of a flower and collectively form the androecium. Finally in the middle there are carpels, which at maturity contain one or more ovules, and within each ovule is a tiny female gametophyte. Carpels may be called the "female" parts of a flower and collectively form the gynoecium.' back |
Plato - Wikipedia, Plato - Wikipedia, the free encyclopedia, ' Plato (c. 427 – 348 BC) was an ancient Greek philosopher of the Classical period who is considered a top thinker in Philosophy. Plato founded the Academy, a philosophical school in Athens where Plato taught the doctrines that would later become known as Platonism. The philosopher was an innovator of the written dialogue and dialectic forms in philosophy. He was a system-builder. He also raised problems for what became all the major areas of both theoretical philosophy and practical philosophy.' back |
Plutonium - Wikipedia, Plutonium - Wikipedia, the fee encyclopedia, ' Plutonium is a radioactive actinide metal whose isotope, plutonium-239, is one of the three primary fissile isotopes (uranium-233 and uranium-235 are the other two); plutonium-241 is also highly fissile. To be considered fissile, an isotope's atomic nucleus must be able to break apart or fission when struck by a slow moving neutron and to release enough additional neutrons to sustain the nuclear chain reaction by splitting further nuclei.' back |
Principia Mathematica - Wikipedia, Principia Mathematica - Wikipedia, the free encyclopedia, 'The Principia Mathematica (often abbreviated PM) is a three-volume work on the foundations of mathematics written by the mathematicians Alfred North Whitehead and Bertrand Russell and published in 1910, 1912, and 1913.PM, . . . PM, according to its introduction, had three aims: (1) to analyze to the greatest possible extent the ideas and methods of mathematical logic and to minimize the number of primitive notions and axioms, and inference rules; (2) to precisely express mathematical propositions in symbolic logic using the most convenient notation that precise expression allows; (3) to solve the paradoxes that plagued logic and set theory at the turn of the 20th century, like Russell's paradox.' back |
Quantum chromodynamics - Wikipedia, Quantum chromodynamics - Wikipedia, the free encyclopedia, ' In theoretical physics, quantum chromodynamics (QCD) is the theory of the strong interaction between quarks and gluons, the fundamental particles that make up composite hadrons such as the proton, neutron and pion. QCD is a type of quantum field theory called a non-abelian gauge theory, with symmetry group SU(3). The QCD analog of electric charge is a property called color. Gluons are the force carrier of the theory, like photons are for the electromagnetic force in quantum electrodynamics.' back |
Quark - Wikipedia, Quark - Wikipedia, the free encyclopedia, 'Quarks . . . are a type of elementary particle and major constituents of matter. They combine to form composite particles called hadrons, the most well-known of which are protons and neutrons. They are the only particles in the Standard Model to experience the strong force, and thereby the only particles to experience all four fundamental forces, which are also known as fundamental interactions.' back |
Richard P. Feynman (1981), Simulating Physics with Computers, 'I want to talk about the possibiilty that there is to be an exact simulation, that the computer will do exactly the same as nature. If this is to be proved and the type of computer is as I've already explained, then it's going to be necessary that everything that happens in a finite volume of space and time would have to be exactly analyzable with a finite number of logical operations. The present theory of physics is not that way, apparently. It allows space to go down into infinitesimal distances, wavelengths to get infinitely great, terms to be summed in infinite order, and so forth; and therefore if this proposition is right, physical law is wrong.'
International Journal of Theoretical Physics, VoL 21, Nos. 6/7, 1982 back |
Riemannian geometry - Wikipedia, Riemannian geometry - Wikipedia, the free encyclopedia, ' Riemannian geometry is the branch of differential geometry that studies Riemannian manifolds, smooth manifolds with a Riemannian metric, i.e. with an inner product on the tangent space at each point that varies smoothly from point to point. This gives, in particular, local notions of angle, length of curves, surface area, and volume. From those some other global quantities can be derived by integrating local contributions. . . . It enabled Einstein's general relativity theory, made profound impact on group theory and representation theory, as well as analysis, and spurred the development of algebraic and differential topology.' back |
Rule of Saint Augustine - Wikipedia, Rule of Saint Augustine - Wikipedia, the free encyclopedia, ' The Rule of Saint Augustine, written in about the year 400, is a brief document divided into eight chapters and serves as an outline for religious life lived in community. It is the oldest monastic rule in the Western Church.
The rule, developed by Augustine of Hippo (354–430), governs chastity, poverty, obedience, detachment from the world, the apportionment of labour, the inferiors, fraternal charity, prayer in common, fasting and abstinence proportionate to the strength of the individual, care of the sick, silence and reading during meals. . . ..
At the Fourth Lateran Council (1215) it was accepted as one of the approved rules of the church. It was then adopted by the Order of Preachers in 1216 when their order received papal recognition. back |
Shelter Island Conference - Wikipedia, Shelter Island Conference - Wikipedia, the free encyclopedia, ' The first Shelter Island Conference on the Foundations of Quantum Mechanics was held from June 2–4, 1947 at the Ram's Head Inn in Shelter Island, New York. Shelter Island was the first major opportunity since Pearl Harbor and the Manhattan Project for the leaders of the American physics community to gather after the war. As Julian Schwinger would later recall, "It was the first time that people who had all this physics pent up in them for five years could talk to each other without somebody peering over their shoulders and saying, 'Is this cleared?" ' back |
Shelter Island Conference - Wikipedia, Shelter Island Conference - Wikipedia, the free encyclopedia, ' The first Shelter Island Conference on the Foundations of Quantum Mechanics was held from June 2–4, 1947 at the Ram's Head Inn in Shelter Island, New York. Shelter Island was the first major opportunity since Pearl Harbor and the Manhattan Project for the leaders of the American physics community to gather after the war. As Julian Schwinger would later recall, "It was the first time that people who had all this physics pent up in them for five years could talk to each other without somebody peering over their shoulders and saying, 'Is this cleared?" ' back |
Space (mathematics) - Wikipedia, Space (mathematics) - Wikipedia, the free encyclopedia, ' n mathematics, a space is a set (sometimes called a universe) with some added structure. While modern mathematics uses many types of spaces, such as Euclidean spaces, linear spaces, topological spaces, Hilbert spaces, or probability spaces, it does not define the notion of "space" itself.
A space consists of selected mathematical objects that are treated as points, and selected relationships between these points. The nature of the points can vary widely: for example, the points can be elements of a set, functions on another space, or subspaces of another space. It is the relationships that define the nature of the space.' back |
Standard model - Wikipedia, Standard model - Wikipedia, the free encyclopedia, 'The Standard Model of particle physics is a theory that describes three of the four known fundamental interactions between the elementary particles that make up all matter. It is a quantum field theory developed between 1970 and 1973 which is consistent with both quantum mechanics and special relativity. To date, almost all experimental tests of the three forces described by the Standard Model have agreed with its predictions. However, the Standard Model falls short of being a complete theory of fundamental interactions, primarily because of its lack of inclusion of gravity, the fourth known fundamental interaction, but also because of the large number of numerical parameters (such as masses and coupling constants) that must be put "by hand" into the theory (rather than being derived from first principles) . . . ' back |
Tensor product - Wikipedia, Tensor product - Wikipedia, the free encyclopedia, ' In mathematics, the tensor product V ⊗ W of two vector spaces V and W (over the same field) is itself a vector space, endowed with the operation of bilinear composition, denoted by ⊗, from ordered pairs in the Cartesian product V × W to V ⊗ W in a way that generalizes the outer product.
Essentially the difference between a tensor product of two vectors and an ordered pair of vectors is that if one vector is multiplied by a nonzero scalar and the other is multiplied by the reciprocal of that scalar, the result is a different ordered pair of vectors, but the same tensor product of two vectors.
The tensor product of V and W is the vector space generated by the symbols v ⊗ w, with v ∈ V and w ∈ W, in which the relations of bilinearity are imposed for the product operation ⊗, and no other relations are assumed to hold. The tensor product space is thus the "freest" (or most general) such vector space, in the sense of having the fewest constraints.' back |
The Principles of Quantum Mechanics - Wikipedia, The Principles of Quantum Mechanics - Wikipedia, the free encyclopedia, The Principles of Quantum Mechanics is an influential monograph on quantum mechanics written by Paul Dirac and first published by Oxford University Press in 1930. Dirac gives an account of quantum mechanics by "demonstrating how to construct a completely new theoretical framework from scratch"; "problems were tackled top-down, by working on the great principles, with the details left to look after themselves". It leaves classical physics behind after the first chapter, presenting the subject with a logical structure. Its 82 sections contain 785 equations with no diagrams.' back |
Theodicy - Wikipedia, Theodicy - Wikipedia, the free encyclopedia, ' In the philosophy of religion, a theodicy (meaning 'vindication of God', from Ancient Greek θεός theos, "god" and δίκη dikē, "justice") is an argument that attempts to resolve the problem of evil that arises when omnipotence, omnibenevolence, and omniscience are all simultaneously ascribed to God. Unlike a defence, which merely tries to demonstrate that the coexistence of God and evil is logically possible, a theodicy additionally provides a framework wherein God's existence is considered plausible. The German philosopher and mathematician Gottfried Leibniz coined the term "theodicy" in 1710 in his work Théodicée, though numerous attempts to resolve the problem of evil had previously been proposed.' back |
Three-body problem - Wikipedia, Three-body problem - Wikipedia, the free encyclopedia, ' In physics and classical mechanics, the three-body problem is the problem of taking the initial positions and velocities (or momenta) of three point masses and solving for their subsequent motion according to Newton's laws of motion and Newton's law of universal gravitation.[1] The three-body problem is a special case of the n-body problem. Unlike two-body problems, no general closed-form solution exists,[1] as the resulting dynamical system is chaotic for most initial conditions, and numerical methods are generally required.
Historically, the first specific three-body problem to receive extended study was the one involving the Moon, Earth, and the Sun.[2] In an extended modern sense, a three-body problem is any problem in classical mechanics or quantum mechanics that models the motion of three particles.' back |
Turing's Proof - Wikipedia, Turing's Proof - Wikipedia, the free encyclopedia, 'Turing's proof is a proof by Alan Turing, first published in January 1937 with the title "On Computable Numbers, with an Application to the Entscheidungsproblem." It was the second proof of the assertion (Alonzo Church's proof was first) that some decision problems are "undecidable": there is no single algorithm that infallibly gives a correct "yes" or "no" answer to each instance of the problem. In his own words: "...what I shall prove is quite different from the well-known results of Gödel ... I shall now show that there is no general method which tells whether a given formula U is provable in K [Principia Mathematica]..." '. back |
Uranium-235 - Wikipedia, Uranium-235 - Wikipedia, the free encyclopedia, ' Uranium-235 (235U or U-235) is an isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a nuclear chain reaction. It is the only fissile isotope that exists in nature as a primordial nuclide.
Uranium-235 has a half-life of 703.8 million years. It was discovered in 1935 by Arthur Jeffrey Dempster. Its fission cross section for slow thermal neutrons is about 584.3±1 barns. For fast neutrons it is on the order of 1 barn.' back |
Vacuum polarization - Wikipedia, Vacuum polarization - Wikipedia, the free encyclopedia, ' In quantum field theory, and specifically quantum electrodyn amics, vacuum polarization describes a process in which a background electromagnetic field produces virtual electron–positron pairs that change the distribution of charges and currents that generated the original electromagnetic field. It is also sometimes referred to as the self-energy of the gauge boson (photon).
After developments in radar equipment for World War II resulted in higher accuracy for measuring the energy levels of the hydrogen atom, I.I. Rabi made measurements of the Lamb shift and the anomalous magnetic dipole moment of the electron. These effects corresponded to the deviation from the value −2 for the spectroscopic electron g-factor that are predicted by the Dirac equation. Later, Hans Bethe theoretically calculated those shifts in the hydrogen energy levels due to vacuum polarization on his return train ride from the Shelter Island Conference to Cornell.' back |
Xavier Waintal (2023_12_29), The Quantum House Of Cards, ' Quantum computers have been proposed to solve a number of important problems such as discovering new drugs, new catalysts for fertilizer production, breaking encryption protocols, optimizing
financial portfolios, or implementing new artificial intelligence applications. Yet, to date, a simple task such as multiplying 3 by 5 is beyond existing quantum hardware. This article examines
the difficulties that would need to be solved for quantum computers to live up to their promises. I discuss the whole stack of technologies that has been envisioned to build a quantum computer from the top layers (the actual algorithms and associated applications) down to the very bottom ones (the quantum hardware, its control electronics, cryogeny, etc.) while not forgetting the crucial intermediate layer of quantum error correction.' back |
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