Band geometry, Berry curvature and superfluid weight

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2017-01-27
Major/Subject
Mcode
Degree programme
Language
en
Pages
1-16
Series
PHYSICAL REVIEW B, Volume 95, issue 2
Abstract
We present a theory of the superfluid weight in multiband attractive Hubbard models within the Bardeen-Cooper-Schrieffer (BCS) mean field framework. We show how to separate the geometric contribution to the superfluid weight from the conventional one, and that the geometric contribution is associated with the interband matrix elements of the current operator. Our theory can be applied to systems with or without time reversal symmetry. In both cases the geometric superfluid weight can be related to the quantum metric of the corresponding noninteracting systems. This leads to a lower bound on the superfluid weight given by the absolute value of the Berry curvature. We apply our theory to the attractive Kane-Mele-Hubbard and Haldane-Hubbard models, which can berealized in ultracold atom gases. Quantitative comparisons are made to state of the art dynamical mean-field theory and exact diagonalization results.
Description
| openaire: EC/FP7/340748/EU//CODE | openaire: EC/H2020/702281/EU//FLATOPS
Keywords
Condensed Matter - Superconductivity, Condensed Matter - Quantum Gases
Other note
Citation
Liang, L, Vanhala, T I, Peotta, S, Siro, T, Harju, A & Törmä, P 2017, ' Band geometry, Berry curvature and superfluid weight ', Physical Review B, vol. 95, no. 2, 024515, pp. 1-16 . https://doi.org/10.1103/PhysRevB.95.024515