[quantum-info] Q+ Hangout: Fernando G.S.L. Brandão Tue, February 26, 9:00 AM; QNC 3206

[Aharon Brodutch]

Hi All

We will be joining the next Q+ Hangout next Tuesday at 9am in QNC 3206.


 Speaker: Fernando G.S.L. Brandão

Title: Exponential decay of correlations implies area law

Abstract:
Quantum states of many particles are fundamental to our understanding of
many-body physics. Yet they are extremely daunting objects, requiring in
the worst case an exponential number of parameters in the number of
subsystems to be even approximately described. How then can multi-particle
states be useful for giving predictions to physical observables? The
intuitive explanation is that physically relevant quantum states, defined
as the ones appearing in nature, are usually much simpler than generic
quantum states. In this talk I will discuss a recent result that gives
further justification to this intuition.

The result shows that exponential decay of correlations, a physically
motivated restriction on the set of multi-particle quantum states, implies
an area law for the entanglement entropy of systems defined on a line, and
thus also an efficient classical description for such systems. The result
can be seen as a rigorous justification to the intuition that states with
exponential decay of correlations, usually associated with non-critical
phases of matter, are simple to describe.

I will outline the main ideas in the proof, that relies on several previous
tools from quantum information theory, such as the state merging protocol,
and that can also be seen as providing a limitation to the phenomenon of
data hiding in quantum states.

Based on arXiv:1206.2947, joint work with Michal Horodecki.


Official website:http://gplus.to/qplus


Cheers
 Aharon


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