Chern number and Berry curvature for Gaussian mixed states of fermions
Wawer L, Fleischhauer M (2021)
Publication Type: Journal article
Publication year: 2021
Journal
Book Volume: 104
Article Number: 094104
Journal Issue: 9
DOI: 10.1103/PhysRevB.104.094104
Abstract
We generalize the concept of topological invariants for mixed states based on the ensemble geometric phase (EGP) to two-dimensional band structures. In contrast to the geometric Uhlmann phase for density matrices, the EGP leads to a proper Chern number for Gaussian, finite-temperature, or nonequilibrium steady states. The Chern number can be expressed as an integral of the ground-state Berry curvature of a fictitious lattice Hamiltonian, constructed from single-particle correlations. For the Chern number to be nonzero the fictitious Hamiltonian has to break time-reversal symmetry.
Involved external institutions
Germany (DE)How to cite
APA:
Wawer, L., & Fleischhauer, M. (2021). Chern number and Berry curvature for Gaussian mixed states of fermions. Physical Review B, 104(9). https://dx.doi.org/10.1103/PhysRevB.104.094104
MLA:
Wawer, Lukas, and Michael Fleischhauer. "Chern number and Berry curvature for Gaussian mixed states of fermions." Physical Review B 104.9 (2021).
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