It has been realized that the measurement problem in quantum mechanics is essentially the determinateexperience problem. The problem is to explain how the linear quantum dynamics can be compatible with the existence of our definite experience. This means that in order to finally solve the measurement problem it is necessary to analyze the observer who is physically in a superposition of brain states with definite measurement records. Indeed, such quantum observers exist in all main realistic solutions to the measurement problem, including Bohm’s theory, Everett’s theory, and even the dynamical collapse theories. Then, what does it feel like to be a quantum observer? Although these theories, as well as the bare theory, give their respective answers to this intriguing question, it is still unknown what the true answer is. It can be expected that the answer, once it has been obtained, will have significant implications for solving the measurement problem.
In parallel with the Physics of the Observer Program and RFP announced by FQXi, we will host an online Workshop on Quantum Observers from 9th January 2016 to 19th January 2016. The workshop will bring together leading experts in the field, and address the most pressing issues in understanding quantum observers and solving the measurement problem.
Based on the successful experience from First iWorkshop on the Meaning of the Wave Function, John Bell Workshop 2014 and Quantum Foundations Workshop 2015, this workshop will be also selforganized to a large extent. Every member may create a topic in the workshop forum on his own, which gives a concise introduction to his ideas to be discussed, and which also states the date and time of his twohour discussion. Then other members can leave comments beforehand or participate in the discussions by text chat in the forum in the twohour duration at the time.
The list of participants and the schedule of this workshop will be announced soon. Selected presentations in this workshop will be published in International Journal of Quantum Foundations.
Note: This is not a public workshop. Group content and activity will only be visible to members of the group, most of who are invited. If you would like to participate in the workshop, please log in or contact us.




Jiri Soucek replied to the topic Does the psiepistemic view really solve the measurement problem? in the forum 2016 International Workshop on Quantum Observers 2 years, 8 months ago
Dear Matthew Leifer,
Thank you very much for your comments. These are very helpful for me. In general I agree with your remarks but some points are to be discussed.
In general, it is clear that QM must be an applied probability theory and it is clear that this probability theory cannot be the Kolmogorovian probability theory.
1. The first…[Read more]

Jiri Soucek replied to the topic The measurement problem revisited in the forum 2016 International Workshop on Quantum Observers 2 years, 9 months ago
Dear Shan,
I have a comment and a critical remark to your argumentation.
I shall consider the property (C1) in the more complete formulation:
(C1x) the wave function of a physical system is a complete description of the individual system.
You write “The first approach is to deny the claim (C1), and add some additional variables …”.
I think…[Read more] 
Matthew Leifer replied to the topic Does the psiepistemic view really solve the measurement problem? in the forum 2016 International Workshop on Quantum Observers 2 years, 9 months ago
jiri soucek,
I am somewhat sympathetic to the view that quantum theory should be understood in terms of some sort of nonKolmogorovian probability theory. However, there are a couple of problems with this.
First, it is not just since 2008 that this option has existed. There are currently a few dozen competing generalized probability theories…[Read more]

Ken Wharton replied to the topic Does the psiepistemic view really solve the measurement problem? in the forum 2016 International Workshop on Quantum Observers 2 years, 9 months ago
Hi Shan,
Turning back to your question in #3303, concerning randomness:
A central point of the paper I posted in this forum is that all of the probabilities in retrocausal quantum models can be classical/conventional in the sense that they all result from a lack of knowledge. But there are two different parts of this. First is the knowledge…[Read more]

Matthew Leifer replied to the topic Does the psiepistemic view really solve the measurement problem? in the forum 2016 International Workshop on Quantum Observers 2 years, 9 months ago
Shan,
“In fact, the writing of this paper is mainly motivated by your words in your review paper. You said, “A straightforward resolution of the collapse of the wavefunction, the measurement problem, Schrodinger’s cat
and friends is one of the main advantages of psiepistemic interpretations…. The measurement problem is not so much resolved by ps…[Read more] 
Jiri Soucek replied to the topic Does the psiepistemic view really solve the measurement problem? in the forum 2016 International Workshop on Quantum Observers 2 years, 9 months ago
Dear Matthew,
I have some comments
1) The very idea of the ontological models is based on the assumption that there exists only one probability theory – the standard Kolmogorov theory. But from 2008 there exist two probability theories – the Kolmogorov (linear) probability theory and the new quadratic probability theory published in…[Read more]

Jiri Soucek replied to the topic Does the psiepistemic view really solve the measurement problem? in the forum 2016 International Workshop on Quantum Observers 2 years, 9 months ago
Dear Shan,
I am suprised that you consider the psiepistemic view together with the idea that all observables have preexisting values.
I understand the psiontic view as the standard assumption that each pure state represents the possible state of an individual system. For me the psiepistemic view means that not all pure states represent the…[Read more] 
Mark Stuckey replied to the topic Does the psiepistemic view really solve the measurement problem? in the forum 2016 International Workshop on Quantum Observers 2 years, 9 months ago
Thnx for the reply, Yehonatan. You don’t need to concern yourself with the details of our approach, as you noted it doesn’t bear directly on your specific motives. I just wanted you to be aware of the fact that your 4D global perspective has company 🙂

Shan Gao replied to the topic Does the psiepistemic view really solve the measurement problem? in the forum 2016 International Workshop on Quantum Observers 2 years, 9 months ago
Hi Matt,
Thanks for your interesting comments, some of which I basically agree.
But I think you misunderstood my paper. The paper does not aim to show the (realist) psiepistemic view cannot solve the measurement problem. Rather, it only shows that the psiepistemic view does not provide a straightforward resolution or a dissolution of the…[Read more]

Matthew Leifer replied to the topic Does the psiepistemic view really solve the measurement problem? in the forum 2016 International Workshop on Quantum Observers 2 years, 9 months ago
Shan,
We have had so many discussions about this now that I am beginning to think that you are being deliberately obtuse, and trying to court controversy where there ought to be none.
Let me first note that not all ontological models solve the measurement problem, psiepistemic or not. Some do and some don’t. Since Bohmian mechanics can be fit…[Read more]

Mark Stuckey replied to the topic Does the psiepistemic view really solve the measurement problem? in the forum 2016 International Workshop on Quantum Observers 2 years, 9 months ago
Yehonatan, I read your paper. Is it published someplace, so we can reference it? Your approach shares many of the values found in the Relational Blockworld. See http://www.ijqf.org/wps/wpcontent/uploads/2015/06/IJQF2015v1n3p2.pdf.

Mark Stuckey replied to the topic Does the psiepistemic view really solve the measurement problem? in the forum 2016 International Workshop on Quantum Observers 2 years, 9 months ago
Shan, there is no superdeterminism in retrocausality with global constraints. Superdeterminism entails a timeevolved story per the Newtonian schema (NS), i.e., invoking a physical mechanism that “causes” the experimentalist to make certain choices. In Wharton’s Lagrangian schema (LS), the explanation is spatiotemporally holistic, e.g., Fermat’s…[Read more]

Arthur Fine replied to the topic Does the psiepistemic view really solve the measurement problem? in the forum 2016 International Workshop on Quantum Observers 2 years, 9 months ago
Shan, Thanks for the post. Here are a few thoughts.
1. You catchout the ontogical models view at a weak point. For what they call “psiepistemic” has to do with possible overlap of ontic states in the preparation of distinct state functions. But that has nothing to do with explaining collapse on measurement. In the earlier literature, as in…[Read more]

Ken Wharton replied to the topic Does the psiepistemic view really solve the measurement problem? in the forum 2016 International Workshop on Quantum Observers 2 years, 9 months ago
Mark: concerning “realist psiepistemic view”. There’s no problem with the basic idea, so long as “realist” clearly modifies “view”. But a different parsing might make it seem that “realist” modifies “psi”, which would imply exactly the opposite of psiepistemic (psiontic). That’s all I was getting at… 🙂

Ken Wharton replied to the topic Does the psiepistemic view really solve the measurement problem? in the forum 2016 International Workshop on Quantum Observers 2 years, 9 months ago
Shan: I’m not sure what you mean by “essential randomness”, or whether that would be ‘good’ or ‘bad’. But you are correct to imply that if there is some ‘special observable’ A in the real system that is perfectly correlated with the measurement B that we utilize on that system, then this correlation needs to be explained causally.
One option is…[Read more]

Mark Stuckey replied to the topic Does the psiepistemic view really solve the measurement problem? in the forum 2016 International Workshop on Quantum Observers 2 years, 9 months ago
Ken, why do you think “realist psiepistemic view” is “an interesting choice of words”? The title of our last RBW paper in IJQF was “Relational blockworld: Providing a realist psiepistemic account of quantum mechanics” which we wrote after extensive correspondence with you.

Ken Wharton replied to the topic Does the psiepistemic view really solve the measurement problem? in the forum 2016 International Workshop on Quantum Observers 2 years, 9 months ago
Thanks for this, Shan.
I’m worried you’re setting up a bit of a straw man version of psiepistemic models (you call it the “realist psiepistemic” view, an interesting choice of words). I’d be surprised if there were many (or any!) quantum foundations people who take such a view.
Specifically, you are ascribing the following logic to anyone…[Read more]
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