I Reading materials on quantum foundations

[WWCY]

Hi all,

I have been trying to read up on quantum foundations after being first introduced to it on this Perimeter Institute page:
https://www.perimeterinstitute.ca/r.../quantum-foundations/more-quantum-foundations

However, I have had difficulty finding notes and papers on this topic. Could anyone provide a few links to notes on the subject that are accessible to an undergraduate reader?

Many thanks in advance!

 

[DarMM]

I would start with Matt Leifer's paper here:
https://arxiv.org/abs/1409.1570

It proves all of the current major results except the Frauchiger-Renner theorem and the Pusey-Leifer theorem and gives the current terminology used in the field.

I'll be frank, I think unless one knows all the material in that paper well to the point of understanding the proofs, there's no point in talking about Quantum Foundations as you'll be out of date.

 

[WWCY]

I would start with Matt Leifer's paper here:
https://arxiv.org/abs/1409.1570

It proves all of the current major results except the Frauchiger-Renner theorem and the Pusey-Leifer theorem and gives the current terminology used in the field.

I'll be frank, I think unless one knows all the material in that paper well to the point of understanding the proofs, there's no point in talking about Quantum Foundations as you'll be out of date.

Thank you, appreciate the reference!

 

[DarMM]

Thank you, appreciate the reference!

Just to be clear on my last line, you'll find many people on the net talking about the implications of the PBR theorem for example, if you read through that paper you'll see the vast majority of them are wrong. Also people underestimate the scope of the theorems, thinking various ideas might dodge them when they don't. Reading Leifer's gives you a real advantage on quickly assessing who is talking nonsense or not.

If you've any questions about the paper as you read it don't hesitate to ask.

 

[Demystifier]

Could anyone provide a few links to notes on the subject that are accessible to an undergraduate reader?

Something more basic and less narrow than Leifer:
Laloe: http://de.arxiv.org/abs/quant-ph/0209123
Me: http://de.arxiv.org/abs/quant-ph/0609163

 

[DarMM]

Those are great papers @Demystifier , I'd read them before what I recommended @WWCY .

 

[WWCY]

Apologies for the late response. Thanks for the additional references @Demystifier !

 

[Demystifier]

I am preparing presentations for introductory lectures on quantum foundations. So far I have prepared 3 of them, so I would like to share them with you. The first is finished completely (the actual talk went well), while the second and third are 95% finished drafts. Possible comments (e.g. typos and suggestions for improvements) would be welcome too.

 

[WWCY]

I am preparing presentations for introductory lectures on quantum foundations. So far I have prepared 3 of them, so I would like to share them with you. The first is finished completely (the actual talk went well), while the second and third are 95% finished drafts. Possible comments (e.g. typos and suggestions for improvements) would be welcome too.

Hi @Demystifier , I'll definitely give the slides a read-through. Really appreciate the gesture.

Is the content in these slides a "condensed" version of your "QM: Myth and Facts" paper?

 

[Demystifier]

Is the content in these slides a "condensed" version of your "QM: Myth and Facts" paper?

No. It's quite complementary to Myths and Facts.

 

[Elias1960]

I would start with Matt Leifer's paper here:
https://arxiv.org/abs/1409.1570

It proves all of the current major results except the Frauchiger-Renner theorem and the Pusey-Leifer theorem and gives the current terminology used in the field.

I'll be frank, I think unless one knows all the material in that paper well to the point of understanding the proofs, there's no point in talking about Quantum Foundations as you'll be out of date.

It is a good review, with a lot of useful additional explanations.

But it has a problem, namely, that it misses that an epistemic interpretation of the wave function exists:

Caticha, A. (2011). Entropic Dynamics, Time and Quantum Theory, J. Phys. A 44 , 225303, arxiv:1005.2357

But this seems to be not a problem of Leifer, but of the whole community, which continues to design proofs of the non-existence of something which is already known to exist.

Then, I doubt that issue is only one particular issue, and not the most important one, about the foundations of quantum theory.

 

[Elias1960]

Possible comments (e.g. typos and suggestions for improvements) would be welcome too.

Lecture 1:

Interpretation ruled out: - measurement reveales values that existed before the measurement.

Add "every". Kochen-Specker does not rule out that some measurements (say of position in dBB) reveal preexisting values.

Then, reevaluate the part about PBR after reading

Caticha, A. (2011). Entropic Dynamics, Time and Quantum Theory, J. Phys. A 44 , 225303, arxiv:1005.2357

The key point is that in an objective Bayesian interpretation of the wave function the information which defines the pure state is something which really exists - but outside the system itself: The preparation measurement device and its final state (or record of the result). So, the state of reality itself will define the wave function. But not the state of the system, only the state of the whole universe.

 

[PeterDonis]

Moderator's note: Moved thread to the quantum foundations and interpretations forum.

 

[Demystifier]

it misses that an epistemic interpretation of the wave function exists:

Caticha, A. (2011). Entropic Dynamics, Time and Quantum Theory, J. Phys. A 44 , 225303, arxiv:1005.2357

Does it define "epistemic" in the same way as PBR? I think it doesn't.

 

[Elias1960]

Does it define "epistemic" in the same way as PBR? I think it doesn't.

It doesn't. This does not change the point that the interpretation of the wave function is epistemic. More epistemic than Caticha is not possible in principle. He comes from the entropic inference community which started, following Jaynes, to reinterpret the whole of statistical physics in terms of the objective Bayesian interpretation as describing our incomplete knowledge instead of microphysics instead of some objective state. The phase of the wave function is explicitly (modulo an #\ln \rho##) defined as an entropy, namely that of some other variables (one can use as these the rest of the universe) given the system is in a particular configuration. All the derivations of the equations follow the scheme of entropic inference, thus, the methods developed especially for the problem of how to handle incomplete knowledge.

What is used in the theorems is the non-overlap condition: Incomplete knowledge means that there may be states of reality belonging to different states of incomplete knowledge. Sounds plausible, but only if one distinguishes the state of the system from the state of the whole universe. Because the whole universe contains, for every pure state, also the preparation procedure and the result it has given, thus, also defines the wave function uniquely, without overlap.

 

[Demystifier]

I am preparing presentations for introductory lectures on quantum foundations. So far I have prepared 3 of them, so I would like to share them with you. The first is finished completely (the actual talk went well), while the second and third are 95% finished drafts. Possible comments (e.g. typos and suggestions for improvements) would be welcome too.

Now I have fixed some typos if the first 3 lectures and prepared additional 2 lectures:

 

[A. Neumaier]

Hi all,

I have been trying to read up on quantum foundations after being first introduced to it on this Perimeter Institute page:
https://www.perimeterinstitute.ca/r.../quantum-foundations/more-quantum-foundations

However, I have had difficulty finding notes and papers on this topic. Could anyone provide a few links to notes on the subject that are accessible to an undergraduate reader?

My views on the topic are in the paper linked in the first post here and in the papers and book linked to in the first post here (with a synopsis of the problems primarily in Part I). These cite hundreds of papers of interest, mostly orthogonal to Leiffer's work and to the lectures of Nikolic = Demystifier.