[quantum-info] Q+ hangout - Roger Colbeck - Tuesday Nov 29 at 9:00am

[Aharon Brodutch]

Hi all
For anyone who is interested we will be joining the  q+ Hangout  on Tuesday
in QNC 3206 at 9am.

-
Roger Colbeck (ETH Zurich): No extension of quantum theory can have
improved predictive power

Abstract:
According to quantum theory, measurements generate random outcomes, in
stark contrast with classical mechanics.  This raises the important
question of whether there could exist an extension of the theory which
removes this indeterminism, as famously suspected by Einstein, Podolsky and
Rosen.  Under the assumption of free choice within a particular causal
structure, Bell's work showed this to be impossible.  However, existing
results do not imply that the current theory is maximally informative.
 Could it be that certain hidden variable theories (for example) allow us
to make more accurate predictions about the outcomes?

In this talk, I will discuss this question and show that, under the same
free choice assumption, the answer is negative:  no extension of quantum
theory can give more information about the outcomes of future measurements
than quantum theory itself.

I will then show that as a corollary of this result, we can reach the same
conclusion as Pusey, Barrett and Rudolph that the wavefunction cannot be
thought of as subjective.

(This is based on arXiv:1005.5173, arXiv:1111.6597 and arXiv:1208.4123)
-
Cheers
   Aharon
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