[PhilPhys] Q+ hangout: Roger Colbeck

[Matthew Leifer]

Q+ hangouts is a series of online seminars on quantum information and 
the foundations of quantum theory that takes place in a Google+ 
hangout.  I post announcements to this list when the talk is relevant to 
quantum foundations.  The details of the next talk are as follows:

Date: Tuesday 29th January 2013
Time: 2pm GMT/UTC
Speaker: Roger Colbeck (ETH Zurich)
Title: 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)

To watch the talk live, go to http://gplus.to/qplus at the appointed hour.

To keep up to date on the latest news about Q+ hangouts you can follow 
us on:

Google+: http://gplus.to/qplus
Twitter: @qplushangouts
Facebook: http://facebook.com/qplushangouts
or visit our website: http://qplus.burgarth.de
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