Quantum equilibration in finite time

Anthony J. Short, Terence C. Farrelly

Research output: Contribution to journalArticle (Academic Journal)peer-review

125 Citations (Scopus)


It has recently been shown that small quantum subsystems generically equilibrate, in the sense that they spend most of the time close to a fixed equilibrium state. This relies on just two assumptions: that the state is spread over many different energies, and that the Hamiltonian has non-degenerate energy gaps. Given the same assumptions, it has also been shown that closed systems equilibrate with respect to realistic measurements. We extend these results in two important ways. Firstly, we prove equilibration over a finite (rather than infinite) time-interval, allowing us to bound the equilibration time. Secondly, we weaken the non-degenerate energy gaps condition, showing that equilibration occurs provided that no energy gap is hugely degenerate.

Original languageEnglish
Article number013063
Pages (from-to)-
Number of pages13
JournalNew Journal of Physics
Publication statusPublished - 31 Jan 2012

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