A reminder of Adrian Hutter's talk today at 4pm in the Time room.

Title: A Quantum Information Approach to Statistical Physics

Abstract: I will first present a theorem based on the Decoupling Theorem of [1] which gives sufficient and necessary conditions for a quantum channel (CPTPM) being such that it yields the same output for almost all possible inputs. This theorem allows us to reproduce and generalize results of [2,3], in which cornerstones of statistical physics are derived from first principles of quantum mechanics, in a very natural and easy way. Specifically, we express them in a way which allows to apply results about random 2-qubit interactions [4]. Furthermore, we apply this theorem to provide a criterion for whether different initial states of some subspace of a quantum mechanical system in contact with an environment have at some given time already evolved to the same state or not. As it turns out, this question can be answered by examining a simple entropic inequality evaluated for just one particular state [5]. Applying this criterion to realistic Hamiltonians with local interactions may lead to improved bounds on the thermalization times of quantum mechanical systems. Joint work with Stephanie Wehner.

[1] F. Dupuis, M. Berta, J. Wullschleger, and R. Renner, arXiv:1012.6044v1 (2010).
[2] S. Popescu, A. Short, and A. Winter, Nature Physics 2, 754 (2006).
[3] N. Linden, S. Popescu, A. Short, and A. Winter, New Journal of Physics 12, 055021 (2010).
[4] A. Harrow and R. Low, Communications in Mathematical Physics 291, 257 (2009).
[5] A. Hutter and S. Wehner, arXiv:1111.3080v3 (2011).