Equilibration of quantum gases
 verfasst von
 Terry Farrelly
 Abstract
Finding equilibration times is a major unsolved problem in physics with few analytical results. Here we look at equilibration times for quantum gases of bosons and fermions in the regime of negligibly weak interactions, a setting which not only includes paradigmatic systems such as gases confined to boxes, but also Luttinger liquids and the free superfluid Hubbard model. To do this, we focus on two classes of measurements: (i) coarsegrained observables, such as the number of particles in a region of space, and (ii) fewmode measurements, such as phase correlators. We show that, in this setting, equilibration occurs quite generally despite the fact that the particles are not interacting. Furthermore, for coarsegrained measurements the timescale is generally at most polynomial in the number of particles N, which is much faster than previous general upper bounds, which were exponential in N. For local measurements on lattice systems, the timescale is typically linear in the number of lattice sites. In fact, for onedimensional lattices, the scaling is generally linear in the length of the lattice, which is optimal. Additionally, we look at a few specific examples, one of which consists of N fermions initially confined on one side of a partition in a box. The partition is removed and the fermions equilibrate extremely quickly in time .
 Typ
 Artikel
 Journal
 New journal of physics
 Band
 18
 ISSN
 13672630
 Publikationsdatum
 07.2016
 Publikationsstatus
 Veröffentlicht
 Peerreviewed
 Ja
 ASJC Scopus Sachgebiete
 Physik und Astronomie (insg.)
 Elektronische Version(en)

https://doi.org/10.1088/13672630/18/7/073014 (Zugang:
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