Lezama, Talía L. M. and Bera, Soumya and Schomerus, Henning Ulrich and Heidrich-Meisner, Fabian and Bardarson, Jens H. (2017) One-particle density matrix occupation spectrum of many-body localized states after a global quench. Physical review B, 96 (6): 060202(R). ISSN 2469-9950
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Abstract
The emergent integrability of the many-body localized phase is naturally understood in terms of localized quasiparticles. As a result, the occupations of the one-particle density matrix in eigenstates show a Fermi-liquid-like discontinuity. Here, we show that in the steady state reached at long times after a global quench from a perfect density-wave state, this occupation discontinuity is absent, reminiscent of a Fermi liquid at a finite temperature, while the full occupation function remains strongly nonthermal. We discuss how one can understand this as a consequence of the local structure of the density-wave state and the resulting partial occupation of quasiparticles. This partial occupation can be controlled by tuning the initial state and can be described by an effective temperature.