Mainz 2017 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 34: Quantum Effects: Entanglement and Decoherence
Q 34.5: Vortrag
Mittwoch, 8. März 2017, 15:45–16:00, P 4
Stability of quantum statistical ensembles with respect to local measurements — •Walter Hahn1,2 and Boris V. Fine1,2 — 1Skolkovo Institute of Science and Technology, Moscow (Russia) — 2Institute for Theoretical Physics, University of Heidelberg (Germany)
We introduce a stability criterion for quantum statistical ensembles describing macroscopic systems. An ensemble is called *stable* when a small number of local measurements cannot significantly modify the probability distribution of the total energy of the system. In this talk, we apply this criterion to lattices of spins-1/2 and particularly focus on recent results obtained in numerical simulations of interacting spin systems. Thereby we show that the canonical ensemble is nearly stable, whereas statistical ensembles with much broader energy distributions are not stable. In the context of the foundations of quantum statistical physics, this result justifies the use of statistical ensembles with narrow energy distributions such as canonical or microcanonical ensembles.