SAMOP 2023 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 26: Quantum Gases: Bosons III
Q 26.1: Vortrag
Mittwoch, 8. März 2023, 11:00–11:15, E214
Emergence of damped-localized excitations in the Mott phase due to disorder — Renan Souza1,2, •Axel Pelster1, and Francisco dos Santos2 — 1Physics Department and Research Center OPTIMAS, Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, Germany — 2Departamento de Física, Universidade Federal de São Carlos, Brazil
A key aspect of ultracold bosonic quantum gases in deep optical lattice potential wells is the realization of the strongly interacting Mott insulating phase. Many characteristics of this phase are well understood, however little is known about the effects of a random external potential on its gapped quasiparticle and quasihole low-energy excitations. In the present study we investigate the effect of disorder upon the excitations of the Mott insulating state at zero temperature described by the Bose-Hubbard model. Using a field-theoretical approach we obtain a resummed expression for the disorder ensemble average of the spectral function. Its analysis shows that disorder leads to an increase of the effective mass of both quasiparticle and quasihole excitations. Furthermore, it yields the emergence of damped states, which exponentially decay during propagation in space and dominate the whole band when disorder becomes comparable to interactions. We argue that such damped-localized states correspond to excitations of the Bose-glass phase.