Hamburg 2009 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 9: Quanteninformation: Konzepte II
Q 9.2: Talk
Monday, March 2, 2009, 14:15–14:30, VMP 6 HS-D
Random states with an energy constraint — •Markus Müller1,2, Jens Eisert1, and David Gross3 — 1Institut für Physik, Universität Potsdam, 14476 Potsdam — 2Institut für Mathematik, TU Berlin, 10623 Berlin — 3Institut für Mathematische Physik, TU Braunschweig, 38106 Braunschweig
We consider the question of how and whether thermal states emerge in parts of quantum systems if joint systems are in some random state of fixed energy. It is known that if one draws a random state according to the unitarily invariant measure in a composite system, then states of subsystems will with high probability be very close to being maximally mixed, if the environment is large enough. Here we consider the physically motivated question of looking at properties of random states under a meaningful energy constraint. To discuss this, we invoke techniques from concentration of measure and exploit a weak coupling limit, in an argument that is inspired by quantum information ideas. We outline ideas of how Gibbs states emerge in a weak coupling limit.