Compatibility of Quantum Mechanics and Relativity: Impossible A Priori
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Pentcho Valev
2017-05-28 08:48:17 UTC
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"Professor Hermann Nicolai, Director at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute), has received one of the prestigious Advanced Grants of the European Research Council (ERC). The ERC is funding Prof. Nicolai's research on a unified theory of quantum gravity with approximately €1.9 million. In Nicolai's approach symmetries play a decisive role. One of the greatest challenges in theoretical physics is the unification of quantum field theory and Einstein's general relativity into a theory of quantum gravity. The two fundamental theories are not compatible with each other within the known physical laws. But if we want to understand what happens inside a black hole or at the Big Bang, we need a theory that combines both." http://spaceref.com/news/viewpr.html?pid=50731

If both quantum mechanics and general relativity are deductive theories, one has no right to introduce anything in one of them to make it compatible with the other - unless this "anything" is clearly deducible from the postulates.

If one of the two theories, e.g. general relativity, is not deductive, then it CAN be made compatible with the other. However in this case the question

"If it is not deductive, what is it?"

should be answered. I'am afraid the answer

"An empirical concoction, not even wrong"

is unavoidable.

Pentcho Valev
Pentcho Valev
2017-05-28 17:32:43 UTC
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"The effort to unify quantum mechanics and general relativity means reconciling totally different notions of time. In quantum mechanics, time is universal and absolute; its steady ticks dictate the evolving entanglements between particles. But in general relativity (Albert Einstein's theory of gravity), time is relative and dynamical, a dimension that's inextricably interwoven with directions X, Y and Z into a four-dimensional "space-time" fabric." https://www.quantamagazine.org/20161201-quantum-gravitys-time-problem/

Can you reconcile 2+2=4 and 2+2=5, theoreticians?

"Doublethink means the power of holding two contradictory beliefs in one's mind simultaneously, and accepting both of them. The Party intellectual knows in which direction his memories must be altered; he therefore knows that he is playing tricks with reality; but by the exercise of doublethink he also satisfies himself that reality is not violated. The process has to be conscious, or it would not be carried out with sufficient precision, but it also has to be unconscious, or it would bring with it a feeling of falsity and hence of guilt. Doublethink lies at the very heart of Ingsoc, since the essential act of the Party is to use conscious deception while retaining the firmness of purpose that goes with complete honesty. To tell deliberate lies while genuinely believing in them, to forget any fact that has become inconvenient, and then, when it becomes necessary again, to draw it back from oblivion for just so long as it is needed, to deny the existence of objective reality and all the while to take account of the reality which one denies - all this is indispensably necessary." http://ebooks.adelaide.edu.au/o/orwell/george/o79n/chapter2.9.html

Pentcho Valev
Pentcho Valev
2017-05-29 16:42:02 UTC
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It seems that quantum field theory, just like general relativity, is an empirical concoction (that is, not even wrong), not a deductive theory:

"Quantum Field Theory is an axiomatic theory that rests on a few basic assumptions. Everything you have learned so far, from the force of gravity to the spectrum of hydrogen, follows almost inevitably from these three basic principles. (To my knowledge, Julian Schwinger is the only person who has presented Quatum Field Theory in this axiomatic way, at least in the amazing courses he taught at Harvard University in the 1950's.) 1. The field principle. [...] 2. The quantum principle (discretization). [...] 3. The relativity principle." http://www.quantum-field-theory.net/foundations-quantum-field-theory/

If these are the postulates on which quantum field theory is based, then the constancy of the speed of light is not among the consequences and accordingly the theory is not relativistic in any sense - Lorentz transformations are just added, not deduced from the postulates. Only the silliest Einsteinians believe that the constancy of the speed of light is a consequence of the principle of relativity:

Professor Raymond Flood (5:05): "A consequence of Einstein's principle of relativity is that the speed of light in a vacuum has the same value in two uniformly moving frames of reference."

Dave Slaven: "Einstein's first postulate seems perfectly reasonable. And his second postulate follows very reasonably from his first. How strange that the consequences will seem so unreasonable."

Lubos Motl: "The second postulate of special relativity morally follows from the first one..."

Chad Orzel: "The core idea of Einstein's theory of relativity can fit on a bumper sticker: The Laws Of Physics Do Not Depend On How You're Moving. Absolutely everything else follows from the simple realization that physics must appear exactly the same to person in motion as to a person at rest - the constant speed of light, the slowing of time for moving observers, E=mc2, black holes, even the expanding universe (I've written a whole book about this, explained through imaginary conversations with my dog)."

Michael Fowler: "Therefore, demanding that the laws of physics are the same in all inertial frames implies that the speed of any light wave, measured in any inertial frame, must be 186,300 miles per second. This then is the entire content of the Theory of Special Relativity: the Laws of Physics are the same in any inertial frame, and, in particular, any measurement of the speed of light in any inertial frame will always give 186,300 miles per second."

Vesselin Petkov: "One of the fundamental facts of modern physics is the constancy of the speed of light. Einstein regarded it as one of the two postulates on which special relativity is based. So far, however, little attention has been paid to the status of this postulate when teaching special relativity. It turns out that the constancy of the speed of light is a direct consequence of the relativity principle, not an independent postulate. To see this let us consider the two postulates of special relativity as formulated by Einstein in his 1905 paper "On the electrodynamics of moving bodies": "the same laws of electrodynamics and optics will be valid for all frames of reference for which the equations of mechanics hold good. We will raise this conjecture (the purport of which will hereafter be called the "Principle of Relativity") to the status of a postulate, and also introduce another postulate, which is only apparently irreconcilable with the former, namely, that light is always propagated in empty space with a definite velocity c which is independent of the state of the motion of the emitting body". As the principle of relativity states that "the laws of physics are the same in all inertial reference frames" and the constancy of the speed of light means that "the speed of light is the same in all inertial reference frames (regardless of the motion of the source or the observer)" it follow that the second postulate is indeed a consequence of the first - the law describing the propagation of light is the same for all inertial observers."

Pentcho Valev
Pentcho Valev
2017-05-30 12:14:11 UTC
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The fundamental red herring of quantum gravity:

Only the general relativistic time is at odds with quantum mechanics; the special relativistic time is compatible and quantum mechanics and special relativity successfully work together combined in quantum field theory.

This red herring is so idiotic that even Einsteinians often contradict it, explicitly or implicitly:

"The effort to unify quantum mechanics and general relativity means reconciling totally different notions of time. In quantum mechanics, time is universal and absolute; its steady ticks dictate the evolving entanglements between particles. But in general relativity (Albert Einstein's theory of gravity), time is relative and dynamical, a dimension that's inextricably interwoven with directions X, Y and Z into a four-dimensional "space-time" fabric." x

"In quantum theory, a "master clock" ticks away somewhere in the universe, measuring out all processes. But in Einstein's relativity, time is distorted by motion and gravity, so clocks don't necessarily agree on how it is passing - meaning any master clock must, somewhat implausibly, be outside the universe."

Perimeter Institute: "Quantum mechanics has one thing, time, which is absolute. But general relativity tells us that space and time are both dynamical so there is a big contradiction there. So the question is, can quantum gravity be formulated in a context where quantum mechanics still has absolute time?"

"In Einstein's general theory of relativity, time depends locally on gravity; in standard quantum theory, time is global – all clocks "tick" uniformly."

"One one hand, time in quantum mechanics is a Newtonian time, i.e., an absolute time. In fact, the two main methods of quantization, namely, canonical quantization method due to Dirac and Feynman's path integral method are based on classical constraints which become operators annihilating the physical states, and on the sum over all possible classical trajectories, respectively. Therefore, both quantization methods rely on the Newton global and absolute time. [...] The transition to (special) relativistic quantum field theories can be realized by replacing the unique absolute Newtonian time by a set of timelike parameters associated to the naturally distinguished family of relativistic inertial frames."

"In quantum mechanics, time is absolute. The parameter occurring in the Schrödinger equation has been directly inherited from Newtonian mechanics and is not turned into an operator. In quantum field theory, time by itself is no longer absolute, but the four-dimensional spacetime is; it constitutes the fixed background structure on which the dynamical fields act. GR is of a very different nature. According to the Einstein equations (2), spacetime is dynamical, acting in a complicated manner with energy momentum of matter and with itself. The concepts of time (spacetime) in quantum theory and GR are thus drastically different and cannot both be fundamentally true."

Pentcho Valev