An instability of unitary quantum dynamics

[摘要] Instabilities of equilibrium quantum mechanics are common and well-understood. They are manifested for example in phase transitions, where a quantum system becomes so sensitive to perturbations that a symmetry can be spontaneously broken. Here, we consider the possibility that the time evolution governing quantum dynamics may be similarly subject to an instability, at which its unitarity spontaneously breaks down owing to an extreme sensitivity towards perturbations. We find that indeed such an instability exists, and we explore its immediate consequences. Interpretations of the results both in terms of extreme sensitivity to the influence of environmental degrees of freedom, and in terms of a possible fundamental violation of unitarity are discussed.

[发布机构] Institute for Theoretical Physics, IoP, University of Amsterdam, Amsterdam; 1090 GL, Netherlands^1

[效力级别] 力学 [学科分类] 力学，机械学

[关键词] In-phase;Quantum dynamics;Quantum system;Time evolutions;Unitarity