Puschmann, Martin and Getelina, Joao C. and Hoyos, Jose A. and Vojta, Thomas (2021) Inhomogeneous mean-field approach to collective excitations near the superfluid-Mott glass transition. ANNALS OF PHYSICS, 435: 168526. ISSN 0003-4916, 1096-035X
Full text not available from this repository. (Request a copy)Abstract
We develop an inhomogeneous quantum mean-field approach to the behavior of collective excitations across the superfluid-Mott glass quantum phase transition in two dimensions, complementing recent quantum Monte Carlo simulations (Puschmann et al. 2020). In quadratic (Gaussian) approximation, the Goldstone (phase) and Higgs (amplitude) modes completely decouple. Each is described by a disordered Bogoliubov Hamiltonian which can be solved by an inhomogeneous multi-mode Bogoliubov transformation. We find that the Higgs mode is spatially localized in both phases. The corresponding scalar spectral function shows a broad peak that is noncritical in the sense that its peak frequency does not soften but remains nonzero across the quantum phase transition. In contrast, the lowest-energy Goldstone mode delocalizes in the superfluid phase, leading to a zero-frequency spectral peak. We compare these findings to the results of the quantum Monte Carlo simulations. We also relate them to general results on the localization of bosonic excitations, and we discuss the limits and generality of our approach. (c) 2021 Elsevier Inc. All rights reserved.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | PHASE-TRANSITIONS; QUANTUM; LOCALIZATION; BEHAVIOR; DENSITY; Quantum phase transition; Disorder; Collective excitation; Superfluid; Localization |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Theroretical Physics |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 06 Sep 2022 06:48 |
| Last Modified: | 06 Sep 2022 06:48 |
| URI: | https://pred.uni-regensburg.de/id/eprint/47216 |
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