Recent Physics Theory Resolves Paradoxes

By Rodney Brooks

For one hundred years, most people have seen it impossible to understand physics. Examples include Joseph Heller ("writhing in an exasperating quandary over quantum mechanics"), Bill Clinton ("I hope I can finally understand physics before I leave the earth", Richard Feynman ("One had to lose one's common sense"), and even Albert Einstein ("fifty years of pondering have not brought me any closer to answering the question, what are light quanta?).

Julian Schwinger's Insight to Physics

And yet, there is a concept that makes perfect sense and can be understood by any person. This theory, with origins in the 1930s, was ultimately developed by Julian Schwinger, who once had been considered "the heir-apparent to Einstein's mantle". This success occurred many years after Schwinger had already achieved physics fame for solving the "renormalization" problem, defined by the NY Times as "the most important development in the last 20 years" and was duly awarded the Nobel prize.

However for Schwinger this wasn't good enough. He felt that Quantum Field Theory, as it stood then, was still lacking. His target was to integrate matter fields and force fields on an equivalent basis. Following numerous years of hard work, he presented a collection of five papers entitled "The theory of quantized fields" in 1951-54.

Physicists have been combating a particles-vs.-fields battle for over 100 years. There have been three "rounds", beginning when Einstein's concept of light as a particle (called photon) triumphed over Maxwell's perspective that light is a field. Round 2 happened when Schrödinger's hope for a field theory of matter was overcome by the particle-like behavior that physicists could not ignore. And round 3 happened when Schwinger's field-based solution of renormalization was usurped by Feynman's easier-to-use particle based approach.

For that reason, and others, Schwinger's final advancement of Quantum Field Theory, which he regarded as far more important than his Nobel prize work, has been regretfully ignored, and is undoubtedly not known to most physicists-- and to all of the general public.

Nevertheless there are signs that QFT, in the true Schwingerian sense is reemerging, so in this sense it is a "new" theory There have been a number of books and articles, such as "The Lightness of Being" by Nobel laureate Frank Wilczek, "There are no particles, there are only fields" by Art Hobson, and "Fields of Color- The theory that escaped Einstein" by Rodney Brooks. The last one explains QFT to a lay reader, without any equations, and shows how this remarkable "new" theory" resolves the paradoxes of Relativity, Quantum Mechanics and physics that have confused so many people.

Learn more here!

GRAVITATIONAL WAVES REVEALED

By Rodney A. Brooks
author of "Fields of Color: The Theory That Escaped Einstein".

The current discovery of gravitational waves at LIGO (Laser Interferometer Gravitational-Wave Observatory) has captured the mind of the public. It will stand as one of the great accomplishments of experimental physics, along with the famous Michelson-Morley experiment of 1887 which it resembles. In fact by comparing these two experiments, you will see that comprehending gravitational waves is not as difficult as you believe.

Contraction. Michaelson and Morley measured the speed of light at different times as the earth moved around its orbit. To their - and everyone's - surprise, the speed turned out to be continuous, independent of the earth's motion. This breakthrough caused great consternation until George FitzGerald and Hendrick Lorentz came up with the only feasible explanation: objects in motion contract. Einstein then showed that this contraction is a consequence of his Principles of Relativity, but without saying why they contract (other than a need to conform to his Principles). In fact Lorentz had previously provided a partial explanation by showing that motion affects the way the electromagnetic field interacts with charges, causing objects to contract. However it wasn't until Quantum Field Theory came along that a full explanation was found. In QFT, at least in Julian Schwinger's model, everything is made of fields, even space itself, and motion affects the way all fields interact.

Waves. Electromagnetic waves, e.g., radio waves, have long been recognized and accepted as a natural phenomenon of fields. Now in QFT gravity is a field and, just as an oscillating electron in an antenna sends out radio waves, so a large mass moving back and forth will send out gravitational waves. But it didn't take QFT to show this. Einstein also believed that gravity is a field that obeys his equations, just as the EM field adheres to the equations of James Maxwell. In fact gravitational waves have been recognized by many physicists, from Einstein on down, who regard gravity as a field.

Curvature. But what about "curvature of space-time", which many people today say is what causes gravity? You may be shocked to learn that's not how Einstein saw it. He believed that the gravitational field causes things, even space itself, to contract, comparable to the way motion causes contraction. In fact Einstein used this analogy to show the similarity between motion-induced and gravity-induced contraction: they both affect the way fields work together. It is this gravity-induced contraction that is sometimes called "curvature".

Evidence. The first uncovering of gravitational waves was done at LIGO, using an apparatus similar to Michelson's and Morley's. In both experiments the time for light to travel along two perpendicular paths was compared, but because the gravitational field is much weaker than the EM field, the distances in the LIGO apparatus are much greater (miles instead of inches). Another difference is that while Michelson, not knowing about motion-induced contraction, anticipated to see a change (and found none), the LIGO staff used the known gravity-induced contraction to see an alteration when a gravitational wave passed through.

Fields of Color: The theory that escaped Einstein explains Quantum Field Theory to a lay audience, without any mathematics. If you want to learn more about gravitational waves or about how QFT resolves the paradoxes of Relativity and Quantum Mechanics, read Chapters 1 and 2, which can be seen free at quantum-field-theory.net.

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The Forgotten Genius of Physics

I started my graduate academic work in physics at Harvard University in 1956. Julian Schwinger had just completed his reformulation of Quantum Field Theory and was beginning to instruct a three-year series of courses. I sat mesmerized, as did others.

Attending one of [Schwinger's] formal lectures was comparable to hearing a new major concert by a very great composer, flawlessly performed by the composer himself ... The delivery was magisterial, even, carefully worded, irresistible like a mighty river ... Crowds of students and more senior people from both Harvard and MIT attended ... I felt privileged-- and not a little daunted-- to witness physics being made by one of its greatest masters. - Walter Kohn, Nobel laureate ("Climbing the Mountain" by J. Mehra and K.A. Milton).

As Schwinger stood at the blackboard, writing ambidextrously and speaking mellifluously in well-formed sentences, it was as if God Himself was presenting the Ten Commandments. The equations were so incredible that it seemed the world couldn't be created any other way. From the barest of first basic principles, he discovered all of QFT, even including gravity. Not only was the mathematics beautiful, but the philosophic concept of a world made of properties of space seemed to myself much more satisfying than unexplainable particles. I was amazed and thrilled to discover how all the paradoxes of relativity theory and quantum mechanics that I had previously found so complicated disappeared or were resolved.
However, Schwinger, once referred to as "the heir-apparent to Einstein's mantle" by J. Robert Oppenheimer, never had the effect he should have had on the world of physics or rather on the public at large. It is possible that Schwinger's very elegance was his downfall.

Julian Schwinger was one of the most important and influential scientists of the twentieth century ... Yet even among physicists, recognition of his funda ¬ mental contributions remains limited, in part because his dense formal style ultimately proved less accessible than Feynman's more intuitive approach. However, the structure of modern theoretical physics would be inconceiv ¬ able without Schwinger's manifold insights. His work underlies much of modern physics, the source of which is often unknown even to the practi ¬ tioners. His legacy lives on not only through his work, but also through his many students, who include leaders in physics and other fields.-- "Climbing the Mountain" by J. Mehra and K.A. Milton.

Schwinger is remembered mainly, if he is recalled at all, for figuring out a calculational problem with QFT referred to as renormalization, for which he shared the 1965 Nobel prize with Sin-Itiro Tomanaga and Richard Feynman. Feynman's manner, which had no theoretical basis, proved to be easier to work with than Schwinger's (and Tomanaga's) field-based approach, and Schwinger's method was relegated to the archives. It is Feynman's picture, not Schwinger's, that was enshrined on a postage stamp.

For the rest of the article visit the blog at Fields of Color.

Quantum Field Theory-- A Solution to the "Measurement Problem".

Definition of the "Measurement Problem".

A significant question in physics these days is "the measurement problem", additionally known as "collapse of the "wave-function". The problem arose in the early days of Quantum Mechanics due to the probabilistic nature of the equations. Because the QM wave-function explains only probabilities, the outcome of a physical measurement can only be determined as a probability. This obviously brings about the question: When a measurement is made, at exactly what point is the ultimate result "decided upon". Some folks believed that the duty of the observer was critical, and that the "decision" was generated when someone looked. This led Schrödinger to propose his well-known cat experiment to demonstrate how ridiculous such an idea was. It is not typically known, but Einstein also proposed a bomb experiment for the same reason, saying that "a sort of blend of not-yet and already-exploded systems. can not be a real state of affairs, for in reality there is just no intermediary between exploded and not-exploded." At a later time, Einstein remarked, "Does the moon exist only when I look at it?".

The dispute carries on to this day, with several individuals still thinking that Schrödingers cat remains in a superposition of dead and alive until someone looks. However the majority of people believe that the QM wave-function "collapses" at some earlier point, before the uncertainty reaches a macroscopic level-- with the definition of "macroscopic" being the primary question (e.g., GRW theory, Penrose Interpretation, Physics forum). Several individuals take the "many worlds" view, in which there is no "collapse", but a splitting into various worlds which contain all possible histories and futures. There have been a lot of experiments created to address this issue, e.g., "Towards quantum superposition of a mirror".

We will now find that an unequivocal answer to this issue is offered by Quantum Field theory. However since this theory has been neglected or misunderstood by many physicists, we have to initially specify what we suggest by QFT.

Definition of Quantum Field Theory.
The Quantum Field Theory described here in this article is the Schwinger version in which there are absolutely no particles, there are only fields, not the Feynman version which is based on particles. * The 2 versions are mathematically equivalent, but the concepts backing them are quite different, and it is the Feynman version that is chosen by most Quantum Field Theory physicists.

* According to Frank Wilczek, Feynman ultimately changed his mind: "Feynman informed me that when he realized that his theory of photons and electrons is mathematically equivalent to the usual theory, it crushed his deepest hopes ... He gave up when ... he found the fields introduced for convenience, taking on a life of their own.".

In Quantum Field Theory, as we will use the term henceforward, the world is composed of fields and only fields. Fields are defined as properties of space or, to express it in a different way, space is made of fields. The field concept was presented by Michael Faraday in 1845 as an explanation for electric and magnetic forces. However the principle was not easy for folks to accept and so when Maxwell demonstrated that these particular equations forecasted the existence of EM waves, the concept of an ether was presented to carry the waves. Today, however, it is commonly accepted that space can have properties:.

To deny the ether is essentially to believe that empty space has no physical features whatsoever. The key realities of mechanics do not harmonize with this view.-- A. Einstein (R2003, p. 75).

Moreover space-time itself had come to be a dynamical medium-- an ether, if there ever was one.-- F. Wilczek ("The persistence of ether", Physics Today, Jan. 1999, p. 11).

Although the Schrödinger equation is the non-relativistic limit of the Dirac equation for matter fields, there is a crucial and fundamental distinction between Quantum Field Theory and Quantum Mechanics. One explains the strength of fields at a given point, the other explains the probability that particles could be found at that point, or that a given state exists...

For the rest of the article visit the blog at Fields of Color.

How Quantum Field Theory Solves the "Measurement Problem".

It is not generally understood that Quantum Field Theory gives an easy solution to the "measurement problem" that was examined on the September letters page of Physics Today. But by QFT I do not mean Feynman's particle-based theory; I mean Schwinger's QFT where "there are no particles, there are only fields".1.

The fields are present in the form of quanta, i.e., chunks or units of field, as Planck envisioned over a century ago. Field quanta evolve in a deterministic way specified by the field equations of QFT, except when a quantum suddenly deposits some or all of its energy or momentum into an absorbing atom. This is called "quantum collapse" and it is not defined by the field equations. In fact there is no theory that describes it. Everything we understand is that the probability of it happening depends upon the field strength at a given position. Or, if it is an interior collapse, like a shift in angular momentum, the likelihood depends on the element of angular momentum in the given direction. In QFT this collapse is a physical event, not a mere change in probabilities as in Quantum Mechanics.

Many physicists are troubled by the non-locality of quantum collapse where a spread-out field (or perhaps 2 correlated quanta) unexpectedly disappears or changes its interior condition. Yet non-locality is required if quanta are to serve as a unit, and it has been experimentally proven. It does not result in inconsistencies or paradoxes. It might not be just what we anticipated, but just as we accepted that the world is round, that the planet orbits the sun, that matter is built from atoms, we ought to be able to acknowledge that quanta can collapse.

Sometimes quantum collapse can cause a macroscopic change or "measurement". However the measurement outcome, i.e., the "decision", was determined at the quantum level. Everything after the collapse follows inevitably. There is no "superposition" or "environment-driven process of decoherence.".

Take Schrödinger's cat as an illustration. If a radiated quantum collapses and transfers its energy into 1 or more atoms of the Geiger counter, that initiates a Townsend discharge that leads inexorably to the demise of the cat. In Schrödinger's words, "the counter tube discharges and through a relay releases a hammer which smashes a little flask of hydrocyanic acid" and the cat dies. Alternatively, if it does not collapse in the Geiger counter then the cat lives.

Of course we don't know the result until we look, but we certainly never know anything until we look, no matter if it's throwing dice or choosing a sock blindfolded. The fate of the cat was actually determined at the moment of quantum collapse, just like the outcome of throwing dice is identified when they hit the table and the color of the sock is figured out when it is taken out of the drawer. After the quantum collapse there is no entanglement, no superposition, no decoherence, only lack of knowledge. What could be easier?

In addition to offering an easy solution to the measurement problem, Quantum Field Theory provides a logical explanation for the paradoxes of Relativity (Lorentz contraction, time dilation, etc.) and Quantum Mechanics (wave-particle duality, etc.). It is regrettable that so few physicists have acknowledged QFT in the Schwinger sense.

Find out more on Quantum Field Theory 

The Uncertainty Principle

The probabilistic analysis of Schrödinger's equation at some point resulted in the uncertainty principle of Quantum Mechanics, formulated in 1926 by Werner Heisenberg. This principle says that an electron, or any other particle, can not have its precise position known, or even specified. More exactly, Heisenberg formulated a formula that connects the uncertainty in location of a particle to the uncertainty of its momentum. So not only do we have wave-particle duality to deal with, we need to take care of particles that may be here or may be there, but we just can't say where. If the electron is truly a particle, then it only stands to reason that it should be someplace.

Resolution. In Quantum Field Theory there are no particles (stop me if you have indeed heard this before) and thus no location-- certain or uncertain. Alternatively there are blobs of field that are spread over space. As opposed to a particle that is either here or here or perhaps there, we have a field that is here and here and there. Spreading out is a thing that only a field can do; a particle can not do this. Actually Heisenberg's Uncertainty Principle is not very different from Fourier's Theorem (found in 1807) that relates the spatial spread of any wave to the spread of its wave length.

This does not suggest that there is no uncertainty in Quantum Field Theory. There is uncertainty in regard to field collapse, but field collapse is not explained by the formulas of QFT; Quantum Field Theory can just forecast possibilities of when it happens. Nevertheless there is a significant difference between field collapse in QFT and the corresponding wave-function collapse in QM. The former is an actual physical change in the fields; the latter is just a change in our understanding of where the particle is...

For the full article visit the Fields of Color Blog.

Scientific American, EINSTEIN DIDN'T SAY THAT!

In the September "Einstein" issue of Scientific American, audiences are given the impression that gravity is caused by curvature of space-time. For instance, on the 1st page of that segment, we read "gravity ... is the by-product of a curving universe", on p. 43 we discover that "the Einstein tensor G describes how the geometry of space-time is warped and curved by massive objects", and on p. 56 there is a reference to "Albert Einstein's explanation of how gravity emerges from the bending of space and time".

In reality, many physicist today emphasize "curvature" as the definition for gravity. As Stephen Hawking penned in A Brief History of Time, "Einstein made the revolutionary suggestion that gravity is not a force like other forces, but is a consequence of the fact that space-time is not flat, as had been previously assumed: it is curved, or warped.".

The issue is, that's NOT what Einstein said. Einstein made it rather clear that gravity is a force like other forces, along with (obviously) specific distinctions. In the actual paper cited by Scientific American ("The foundation of the general theory of relativity", 1916) he wrote," [there is] a field of force, namely the gravitational field, which possesses the remarkable property of imparting the same acceleration to all bodies". The G tensor, said Einstein "describes the gravitational field." The term "gravitational field" or just "field" occurs 58 times in this article, while the word "curvature" doesn't turn up at all (except in relation to "curvature of a ray of light"). And Einstein is not the only physicist who believes that. For example Sean Carroll, a prominent physicist of today, wrote:.

Einstein's general relativity describes gravity in terms of a field that is defined at every point in space ... The world is really made out of fields ... deep down it's really fields ... The fields themselves aren't "made of" anything-- fields are what the world is made of ... Einstein's ... "metric tensor"... can be thought of as a collection of ten independent numbers at every point.-- Sean Carroll.

To suppress the field concept and emphasize "curvature" not only misstates Einstein's perspective; it likewise offers folks a false or deceptive understanding of basic relativity.

So where does "curvature" originated from? According to Einstein (in the cited paper), the gravitational field causes physical adjustments in the length of measuring rods (just like temperature can cause such changes) and it is these changes that produce a non-Euclidean metric of space. Actually, as Einstein indicated, these changes can take place even in a space which is without gravitational fields-- i.e., a rotating system. He then showed that this non-Euclidean geometry is mathematically equal to the geometry on a curved surface, which had been developed by Gauss and extended (mathematically) to any number of dimensions by Riemann. That this is a mathematical equivalence is clearly stated by Einstein in a later paper: "mathematicians long ago solved the formal problems to which we are led by the general postulate of relativity".

For the full article visit the blog at Fields of Color.