Einstein Objecting to using Observables

Einstein's unhappiness with quantum mechanics was already clear in 1926, within a year of the theory being formulated.

Heisenberg told this story:

In the spring of 1926, I was invited to address this distinguished body [University of Berlin] on the new quantum mechanics, ...

[Einstein said] "What you have told us sounds extremely strange. You assume the existence of electrons inside the atom, and you are probably quite right to do so. But you refuse to consider their orbits, even though we can observe electron tracks in a cloud chamber. I should very much like to hear more about your reasons for making such strange assumptions."

“We cannot observe electron orbits inside the atom," I must have replied, "but the radiation which an atom emits during discharges enables us to deduce the frequencies and corresponding amplitudes of its electrons. After all, even in the older physics wave numbers and amplitudes could be considered substitutes for electron orbits. Now, since a good theory must be based on directly observable magnitudes, I thought it more fitting to restrict myself to these, treating them, as it were, as representatives of the electron orbits."

"But you don't seriously believe," Einstein protested, "that none but observable magnitudes must go into a physical theory?"

[Heisenberg] "Isn't that precisely what you have done with relativity?" I asked in some surprise. "After all, you did stress the fact that it is impermissible to speak of absolute time, simply because absolute time cannot be observed; that only clock readings, be it in the moving reference system or the system at rest, are relevant to the determination of time."

"Possibly I did use this kind of reasoning," Einstein admitted, "but it is nonsense all the same. Perhaps I could put it more diplomatically by saying that it may be heuristically useful to keep in mind what one has actually observed. But on principle, it is quite wrong to try founding a theory on observable magnitudes alone. In reality the very opposite happens. It is the theory which decides what we can observe.

Einstein is credited with abolishing the aether, absolute space, absolute time, etc., but maybe that is not how he thought about it at all. He went on to try to develop unified field theories that were completely detached from observation.

Generating Quantum Randomness

I posted about someone claiming to prove quantum randomness, and now the journal Nature has published an article on Experimental randomness amplification. The article is paywalled, but here is the 2024 preprint.

In this context, randomness is defined as being fundamentally unpredictable, which means that the laws of physics forbid the prediction of its values. ...

Conventional random number generators, rooted in classical physical processes, grapple with a foundational concern — the potential for adversaries to predict their outputs by scrutinizing the microscopic degrees of freedom, thereby eroding their essential unpredictability.

Quantum-mechanical processes, on the other hand, feature innate randomness and therefore offer a natural ground to build such devices.

This is foolishness. There is no law of physics forbidding prediction.

When you measure X-component of electron spin, then the wave function collapses, and the Y-component has 50-50 chances. Heisenberg uncertainty prohibits measuring the X and Y components at the same time. So the theory is sometimes not able to predict spin. But that is not quite saying that prediction is forbidden. Maybe there is some way to predict, and we do not know how yet.

This paper does not even talk about spin. It merely assumes that you are doing Bell test experiments. Under some assumptions, you can make some random choices, and get even more random outputs.

This method could be used to generate random numbers for practical purposes like cryptography, but I do not think it is any better than tossing coins, or pointing a webcam at a lava lamp.