Who Killed Schrodinger's Cat?

In 1935 Erwin Schrödinger outlined a hypothetical experiment to indicate that something is wrong with the traditional analysis of Quantum Mechanics.

One can even set up quite ridiculous cases. A cat is penned up in a steel chamber, along with the following device (which must be secured against direct interference by the cat): in a Geiger counter there is a tiny bit of radioactive substance, so small that perhaps in the course of the hour one of the atoms decays, but also, with equal probability, perhaps none; if it happens, the counter tube discharges and through a relay releases a hammer which shatters a small flask of hydrocyanic acid. If one has left this entire system to itself for an hour, one would say that the cat still lives if meanwhile no atom has decayed. The [wave-function] of the entire system would express this by having in it the living and dead cat (pardon the expression) mixed or smeared out in equal parts. [1]

Schrödinger's cat quickly became the most famous example of what is now referred to as the measurement problem, "the most controversial problem in physics today", [2] with more than 30 youtube video clips devoted to it. (Less widely known is that Einstein suggested a similar bomb experiment to make the very same point, claiming "a sort of blend of not-yet and already-exploded systems [can not be] a real state of affairs". [3])

The measurement problem arises due to the fact that QM does not offer a picture of reality when no one is looking. Rather we have particles that are neither here nor there, states that are in superpositions, and equations that only give probabilities. The majority of physicists believe that these superpositions are real, and several even acknowledge that the cat can be both half dead and half alive. Then there are physicists who opt not to talk about reality.

I am a positivist who believes that physical theories are just mathematical models we construct, and that it is meaningless to ask if they correspond to reality, just whether they predict observations.-- Stephen Hawking. [4]

Something was obviously missing.

That something came along later in the form of Quantum Field Theory-- a theory that does provide a picture of reality, even when no one is looking. However there are various interpretations and understandings of Quantum Field Theory, while some physicists deny it completely. For instance, N. David Mermin wrote in Physics Today, "I hope you will agree that you are not a continuous field of operators on an infinite-dimensional Hilbert space, [5] and Meinard Kuhlmann wrote in Scientific American, "quantum field theory ... sounds like a theory of fields. Yet the fields supposedly described by the theory are not what physicists classically understand by the term field". [6]

Among those who approve Quantum Field Theory, most follow Richard Feynman's method based on particles and virtual particles, while Julian Schwinger's (and Sin-Itiro Tomonaga's) version, which is based only on fields, is much less well-known. [7] Surprisingly enough, Frank Wilczek reports that Feynman later changed his mind:

Feynman told 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, as he worked out the mathematics of his version of quantum electrodynamics, he found the fields, introduced for convenience, taking on a life of their own. He told me he lost confidence in his program of emptying space. [8]

While both methods lead to the identical equations, the physical pictures are quite different. It is Schwinger's Quantum Field Theory that we refer to in this article, but since this version is so little known, we need to first give a brief description.

Definition of field. A field is a property of space. This idea was proposed by Michael Faraday in 1845 as an explanation for electric and magnetic forces. However the concept that space has properties was not easy to acknowledge, so when James Maxwell predicted the existence of EM waves in 1864, an ether was invented to carry the waves. It took many years before the ether was dispensed with and physicists approved that space itself has properties:

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"SPOOKY ACTION AT A DISTANCE" IS IT REALLY SPOOKY?

"Spooky action at a distance", as Einstein called it, refers to the experimental fact that particles can have an effect on each other instantly, even when separated by large distances. For example, if two photons are created collectively in what is called an entangled state and the angular momentum of one is altered, then the angular momentum of the other one will shift in a corresponding fashion at the same time, no matter how far apart the particles are. This "spooky" behavior has been known for almost a hundred years and still is a source of befuddlement.

Still there is a concept in which the end result is not spooky, but rather a natural consequence. I'm referring to Quantum Field Theory, which identifies a world made only of fields, with no particles. What we refer to as a particle is really a chunk, or quantum, of a field. Quanta are not localized like particles, but are spread out across space. For example, photons are parts of the electromagnetic field and protons are pieces of the matter field. These units evolve in a deterministic way as per the basic field equations and there is a term in these equations that limits the speed of propagation to the velocity of light.

However the QFT equations don't tell the whole story. There are events that are not described by the field equations-- for example, when a field quantum transfers energy or momentum to another object. This event is non-local in the sense that the change in, or even disappearance of, the quantum happens immediately, no matter how spread-out the field may be. It can also happen with two knotted quanta-- no matter how much they are separated. In QFT, this is required if each quanta is to act as a unit, as per the fundamental basis of QFT.

There is a major contrast between quantum collapse in QFT and wave-function collapse in QM. The previous is a real physical change in the fields while the following is a change in our knowledge. Although we don't have a theory to describe quantum collapse, there is nothing irregular about it. To quote from Fields of Color: The theory that escaped Einstein:

In QFT the photon is a spread-out field, and the particle-like activity happens because each photon, or quantum of field, is consumed as a unit ... It is a spread-out field quantum, but when it is absorbed by an atom, the entire field vanishes, no matter how spread-out it is, and all its energy is placed into the atom. There is a big "whoosh" and the quantum is gone, like an elephant disappearing from a magician's theater.

Quantum collapse is not an easy concept to accept-- perhaps more difficult than the concept of a field. Here I have been working hard, trying to convince you that fields are a real property of space-- indeed, the only truth-- and now I am seeking you to accept that a quantum of field, spread out as it may be, quickly disappears into a tiny absorbing atom. Yet it is a process that can be visualized without inconsistency. In fact, if a quantum is an entity that lives and dies as a unit, which is the very meaning of quantized fields, then quantum collapse must take place. A quantum can not separate and put half its energy in one place and half in another; that would violate the fundamental quantum principle. While QFT does not provide a reason for when or why collapse occurs, some day we may have a theory that does. In any case, quantum collapse is vital and has been demonstrated experimentally.

Some physicists, including Einstein, have been bothered by the non-locality of quantum collapse, claiming that it violates an essential postulate of Relativity: that nothing can be sent out quicker than the speed of light. Now Einstein's postulate (which we must keep in mind was only a guess) is without a doubt valid in relation to the evolution and propagation of fields as explained by the field equations. However quantum collapse is not described by the field equations, so there is no reason to assume or to insist that it falls in the domain of Einstein's postulate.

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Dear New York Times

In the article ("With faint chirp, scientists prove Einstein correct", p. A1, 2/12/16) we study that black holes were part of Einstein's theory. The reality is considerably contrary. "Einstein argued vigorously against black holes [as] incompatible with reality" (see "Black Holes" by R. Anderson) and his rivals held back their acceptance for many years.

Einstein was also wrong when he denied Quantum Field Theory. According to his biographer A. Pais," QFT was repugnant to him". This is contradictory because QFT, and only QFT, reveals and resolves the paradoxes of Relativity and Quantum Mechanics that most people struggle with (see "Fields of Color: The theory that escaped Einstein" by this writer).

Perhaps the biggest irony is the statement, "according to Einstein's theory, gravity is caused by objects warping space and time". Although that is what everybody thinks today, the reality is that Einstein recognized gravity as a force field, similar to electromagnetic fields, but that it is created by mass, not charge. That an oscillating mass creates gravitational waves is no more mysterious or unexpected than that electromagnetic waves are generated when electrons move back and forth in an antenna. To Einstein, curvature was a secondary result, similar to the changes in space and time generated by motion according to his Special theory of Relativity.

Black holes. Contrary to numerous reports, black holes were actually not part of Einstein's concept. In fact Einstein argued vigorously against black holes [as] incompatible with reality, and his opposition held back their approval for many years.

Summary. Gravitational waves are easy to understand if you recognize gravity as a force field, similar to the electromagnetic field (QFT). And while the contraction effect is far more subtle, it is not that much different from the F-L contraction that has been accepted for over a hundred years.

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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.

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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.