So in high school in the 80s, quantum mechanics seemed fresh. We read The Dancing Wu Li Masters, which had come out in 1979 (i.e., not that long ago), and it was like mind-blowing stuff!
Recently, however, it occurred to me that I have never heard about a new breakthrough in quantum mechanics in the media. Meanwhile, particle physics has had a bunch of stuff, like the Higgs Boson.
With quantum mechanics, it’s like you hear about really old experiments like the double-slit experiment but nothing new.
Quantum Mechanics is really nothing more than the mathematical treatment of the very small. It imposes new rules that Classical Mechanics never had - thing like certain aspects of nature are quantized (i.e. discreet). The electron circling a proton is either in energy level 1, 2 or 3 and it simply can not be in 1.2.
Now if you combine special relativity and quantum mechanics you wind up with quantum field theory which declares that what we consider particles are actually excitations of the underlying fields which make up reality. That’s what Quantum Electrodynamics and Quantum Chromodynamics gives you - mathematical frameworks to dig deeper into reality to find things like Higgs Bosons.
Am I correct that all the advances in quantum mechanics (not particle physics) during the past 80 years, including quantum computing and teleportation, do not represent any new theory nor unexpected experimental results? All of it follows directly from the theories of the 1920’s of men like Heisenberg and Schrödinger, just as theorems (even if very difficult to prove) and corollaries follow from axioms. (And yes, there’ve been interesting experiments, but weren’t their results predictable from the theories of the 1920’s?)
Bell’s Theorem was published in 1964, and experiments providing evidence for Bell’s Theorem were performed by Aspect in 1981 and by Hansen as recently as 2015.
You are mistaken. Quantum field theories, i.e. the quantum electrodynamics starting with canonical quantization and culimating in renormalization as developed by Feynman, Schwinger, and Tomonaga, all independently, and quantum chromodynamics developed by Gell-Mann and Zweig, were fundamental advances in quantum mechanics that codified the interactions between fundamental (quarks, leptons, and gauge bosons) particles and how they constitude composite particles (baryons and mesons), as well as providing a means to actually model how particles on the quantum scale interact to create macroscopic effects. Quantum field theories are still far from complete; there is a partial theory unifying electrodynamic and weak forces (electroweak), but there is no widely accepted model for a grand unified theory (combining electroweak and strong interactions), and not even a workable quantization of gravity that is consistent with Einstein relativity.
That we are ‘slow’ to advances these theories is a testament to how non-classicial and non-intuitive behavior is at the quantum level, and also the incredible energies required to test predictions of theory. We are only now able to develop sufficient energy and computational analysis capability to detect the Higgs boson using one of the largest and most complex scientific instruments ever constructed, which nonetheless is looking for particles in a fashion akin to performing spectrographic analysis on geological samples by shooting them at each other out of cannons and looking at what color sparks are generated when they impact. The difference in orders of magnitude of energy to explore electrodynamic effects at an observable level and the forces binding together hadrons is so enormous, it is comparable to the difference between flying from New York to LA compared to travelling from our solar system to the center of our galaxy.
By comparison, classical mechanics wasn’t complete until the development of a formal statement of conservation of energy (1847, von Helmholtz) even though Newton published Philosophaie Naturalis Principia Mathematica in 1687. Classical optics and electrodynamics was not really complete until at least the revelation that light is an electromagnetic effect (1873, Maxwell) and not really verified until the discovery of the elecromagnetic spectrum beyond ultraviolet and in the microwave range (1895, Röntegen and Bose), even though the discovery that electromagnetic forces were not an effect of a mechanical medium and a working theory of optics were pronounced (1675, Boyle and Newton, respectively). Classical thermodynamics started with the demonstration of the vacuum pump (von Guericke) and arguably continued through the early 20th Century before the essential concepts of entropy, enthalpy, adiabaticity, and the associated processes and basic cycles were fully formalized and accepted.
The simple parts of what we term quantum mechanics were formalized and tested long ago. The more complicated parts have and continue to take effort that is beyond what just a few bright individual physicists can accomplish. The discoveries remaining are so hard we don’t even have a clear path to figuring them out or testing them, and in fact there may be fundamental limits to how deeply we can even probe into the underlying mechanics, and some physicists suspect that even the most advanced theories are a trivial representation of some more fundamental set of mechanics underlying the apparent randomness of quantum behavior.
I make a distinction between QM itself and particle physics (QED, Standard Model, etc.) Am I wrong that the fundamentals of QM are independent of specific facts about particles?
I had no intention of belittling the work of Feynman, etc. I just wonder if their work was mathematical consequences of basic QM, just as Fermat’s Last Theorem follows from simple axioms.
Consider Bell’s Theorem, for example. Is it not true that the basis for that was available in the 1930’s, just waiting for someone to conceive and publish? There was no need for model refinements or experimental results.
To be clearer about this, the theory of electroweak interactions is, to the best of our considerable ability to determine, fully complete (the predictions of QED have been tested to more decimal places than any other theory in history, and have passed all the tests). It’s incomplete only in so far as it does not include the strong force, of which we have only a rudimentary understanding.
That depends on what you consider fundamentals, what you consider particles, and what you consider specific. Are the ways in which particles interact a feature of the particles, or of the fundamentals? Keep in mind that the mediators of particle interactions are themselves particles: For instance, descriptions of the electromagnetic force can equally well be considered descriptions of the properties of the photon. And Feynman gave us the tools we need to understand perturbative quantum field theories (any perturbative quantum field theories, not just those which describe particles which happen to exist), and that should probably be considered a major advance, but there’s still plenty of room for more advances in non-perturbative quantum field theories, which we’re going to need to understand the strong force.
There is perhaps a too high bar being set by the OP.
Quantum theory was essentially codified 80 years ago. Before that it didn’t really exist, it was a bunch of experimental results and attempts to wrap them into some form of framework. Once the framework came about progress could start. So the OP is essentially asking, for something as big as actually creating the basics of the entire theory. The only way that can be matched is really to overturn QT - which needs new experimental results that can’t be explained, and a new theory that explains both the new results and the old. Like I said, a very high bar.
Although I don’t fully understand the claims being made, it certainly seems to imply that yes–within the scope of applicability of the theory–QM is not only the best there is, but the best there can be.
I just wonder if their work was mathematical consequences of basic QM, just as Fermat’s Last Theorem follows from simple axioms.