No Nobels for quantum foundations

Speculation about this year's Nobel physics prize is starting, and Jennifer Ouellette |

My pick, just to mix things up a bit, was something a bit more esoteric and theoretical: Wojciech (pronounced Voy-check) Zurek, for his many contributions to the fundamentals of quantum mechanics, most notably decoherence and the no-cloning theorem, which forbids the creation of identical copies of an unknown quantum state, with critical implications for quantum computing, quantum teleportation, and quantum information in general. Decoherence is kind of related to the Schroedinger’s Cat thought experiment, specifically the observation question — the notion that once we “look” inside the box, the wave function collapses into a single reality (the cat is either dead or alive).

Einstein once asked Niels Bohr whether Bohr truly believed that the moon is not really there when we don’t happen to be looking at it. Decoherence answers Einstein’s question. It’s like a built-in fail-safe mechanism, ensuring that a large object made of billions of subatomic particles rarely behaves in a truly coherent fashion. It is extremely difficult to get more than a few atoms to vibrate together, perfectly synchronized, because of interference. In the real world, objects interact constantly with the environment, and decoherence occurs instantaneously. So Schrödinger’s macroscopic-yet-quantum cat is an impossible beast. The slightest interaction with the outside world causes the wave function of super-imposed states to gradually fall out of synch, or decohere. The outside interference constitutes an act of measurement. The moon does not exist in isolation. It interacts with everything around it, including the Sun. The rain of photons from the sun’s rays onto the moon’s surface constitutes a “measurement”: the photons interact with the particles that make up the moon, collapsing their respective wave functions and causing decoherence. This gets rid of any super-imposed states, with no need for conscious human interaction. It’s ingenious, really. Definitely Nobel-worthy.

Matt Leifer says:

It means you are a closet Everettian in denial. Zurek is explicit that his work is a development of the Everettian program, although he does not necessarily endorse many-worlds. Still, the only way I can really make sense of Zurek’s work is within a many-worlds context. Zurek would likely disagree, but I think he is working with an unusual definition of “objective”.

I am sure Zurek has done some good work, but I cannot see a Nobel prize for his Quantum Darwinism.

Lumo writes:

You know, decoherence is a genuine process. The insights about it are right and probably needed to explain some aspects of quantum mechanics to those who believe that there is something wrong about quantum mechanics because of what they call the "measurement problem".

But I have increasingly felt that the fans of the word "decoherence" and related words, including Zurek himself, have contributed to the proliferation of quantum flapdoodle – redundant talk about non-existent problems. ...

Decoherence has been around for over 30 years but the obsession with the idea that "something needs to be clarified" hasn't gone away – even though the literature has grown more muddy than it was 30+ years ago.

Even Zurek himself would coin not just one but at least four different words related to decoherence:

pointer states
decoherence
einselection
quantum Darwinism

In reality, the actual idea behind all these things is always the same ...

In other words, "shut up and calculate".

Ouellette also suggests a prize for quantum teleportation. Others have suggested prizes for work testing Bell's theorem or quantum cryptography or quantum computing.

I really don't see how there can be a Nobel prize for foundational work in quantum mechanics when there is no consensus on an interpretation. If anything, the whole field is regressing with more physicists believing in wackier interpretations like many-worlds.