[SydPhil] Foundations of Physics, 5 September *ROOM CHANGE*: Eric Cavalcanti on the quantum state

[Matthew Farr]

The next Sydney Foundations of Physics seminar will be held on Thursday 5th September at 11:30am. Eric Cavalcanti from the School of Physics will speak about the status of the quantum state. Details below.

*Please note* that this and all future FoP seminars will take place in room S401 in the Quad, (aka the 'Muniment Room', or alternatively the 'Price Observatory'), which is where the Time Symmetry conference was held last week. This is down the corridor from the philosophy common room.
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Speaker. Eric Cavalcanti (Sydney).
Title. “No epistemic model can explain the indistinguishability of quantum states.”

Abstract. A recent no-go theorem by Pusey, Barrett and Rudolph (PBR) shows that ψ-epistemic models—for which quantum states represent information about underlying states of reality—are incompatible with the predictions of quantum theory. However, the PBR theorem considers only ψ-epistemic models that satisfy a property called ‘preparation independence’. Later work has shown that without this assumption ψ-epistemic models that reproduce quantum theory can be constructed. This raises the question of which class of ψ-epistemic models can be ruled out without any extra assumptions. Maximally ψ-epistemic models are of specific interest because they fully explain the one-shot indistinguishability of non-orthogonal quantum states in terms of the overlap of the corresponding epistemic states. We show that no maximally ψ-epistemic models can reproduce quantum theory in Hilbert-space dimension greater than 2, and that there is a finite gap between quantum theory and maximally ψ-epistemic models, which allows our result to be experimentally tested. Furthermore, this gap increases with dimension, showing that in the asymptotic limit any model that reproduces quantum theory for the sets of states considered here must be arbitrarily close to ψ-ontic. I will discuss the implications of these results for the epistemic view of quantum states. [Joint work with Jon Barrett, Ray Lal and Owen Maroney.]

Time. Thursday 5th September, 11:30-13:00.
Location. Muniment Room, S401, Main Quad - A14, University of Sydney.
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All are welcome!

Please note that we are seeking speakers for future seminars - any area related to foundational concepts in physics (e.g. space, time, matter, motion, probability, measurement, etc.) is welcome, whether theoretical, philosophical or methodological. If you'd like to give a talk, or know of any future visitors who would like to give a talk, please contact me at matt.farr at sydney.edu.au<mailto:matt.farr at sydney.edu.au>.

The schedule for SydFoP talks is available here: http://newagendasstudyoftime.wordpress.com/sydfop/

Details for how to subscribe to the SydFoP mailing list are here: http://lists.arts.usyd.edu.au/mailman/listinfo/sydfop


All the best
Matt
__________________________________________
DR MATT FARR | Postdoctoral Research Fellow
New Agendas for the Study of Time<http://newagendasstudyoftime.wordpress.com/> | Centre for Time
School of Philosophical and Historical Inquiry | Faculty of Arts and Social Sciences

UNIVERSITY OF SYDNEY
Room N494 | Quadrangle A14
University of Sydney | NSW | 2006

T +61 2 9114 0633<tel:%2B61%202%209114%200633> | F +61 2 9351 3918<tel:%2B61%202%209351%203918>
E matt.farr at sydney.edu.au<mailto:matt.farr at sydney.edu.au>
W mattfarr.co.uk<http://mattfarr.co.uk/>


__________________________________________
DR MATT FARR | Postdoctoral Research Fellow
New Agendas for the Study of Time<http://newagendasstudyoftime.wordpress.com/> | Centre for Time
School of Philosophical and Historical Inquiry | Faculty of Arts and Social Sciences

UNIVERSITY OF SYDNEY
Room N494 | Quadrangle A14
University of Sydney | NSW | 2006

T +61 2 9114 0633<tel:%2B61%202%209114%200633> | F +61 2 9351 3918<tel:%2B61%202%209351%203918>
E matt.farr at sydney.edu.au<mailto:matt.farr at sydney.edu.au>
W mattfarr.co.uk<http://mattfarr.co.uk/>

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