Also, after the meeting will be a talk by Adam Bouland.
-------
Adam Bouland will be speaking at the CTP Graduate Lunch Club on Friday.
When: 12:00 pm, Friday 22 March.
Where: Cosman Seminar Room, 6C-442.
Speaker: Adam Bouland (from CSAIL)
Title: Psi-Epistemic Theories: The Role of Symmetry
(based on
http://arxiv.org/abs/1303.2834)
Abstract: Formalizing an old desire of Einstein, "psi-epistemic
theories" try to reproduce the predictions of quantum mechanics, while
viewing quantum states as ordinary probability distributions over
underlying objects called "ontic states." Regardless of one's
philosophical views about such theories, the question arises of
whether one can cleanly rule them out, by proving no-go theorems
analogous to the Bell Inequality. In the 1960s, Kochen and Specker
(who first studied these theories) constructed an elegant
psi-epistemic theory for Hilbert space dimension d=2, but also showed
that any deterministic psi-epistemic theory must be "measurement
contextual" in dimensions 3 and higher. Last year, the topic attracted
renewed attention, when Pusey, Barrett, and Rudolph (PBR) showed that
any psi-epistemic theory must "behave badly under tensor product." In
this paper, we prove that even without the Kochen-Specker or PBR
assumptions, there are no psi-epistemic theories in dimensions d>=3
that satisfy two reasonable conditions: (1) symmetry under unitary
transformations, and (2) "maximum nontriviality" (meaning that the
probability distributions corresponding to any two non-orthogonal
states overlap). On the other hand, we also show the surprising result
that without the symmetry restriction, one can construct
maximally-nontrivial psi-epistemic theories in every finite dimension
d.
------
On Thu, Mar 21, 2013 at 3:07 PM, Edward Farhi <farhi(a)mit.edu> wrote:
Hi Quanta
We will meet tomorrow, March 22, at 11:00. Vladimir Buzek will join us.
Best,
Eddie
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
Edward Farhi
Cecil and Ida Green Professor of Physics
Director
Center for Theoretical Physics
Massachusetts Institute of Technology
6-300
Cambridge MA 02139
617 253 4871
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