Kramers' degeneracy for open systems in thermal equilibrium
Abstract
Kramers degeneracy theorem underpins many interesting effects in quantum systems with time-reversal symmetry. We show that the generator of dynamics for Markovian open fermionic systems can exhibit an analogous degeneracy, protected by a combination of time-reversal symmetry and the microreversibility (detailed balance) property of systems at thermal equilibrium-the degeneracy is lifted if either condition is not met. We provide simple examples of this phenomenon and show that the degeneracy is reflected in the single-particle Green s functions. Furthermore, we show that certain experimental signatures of topological edge modes in open many-body systems can be protected by microreversibility in the same way. Our results highlight the importance of detailed balance in characterizing open topological matter.
Publication Details
- Authors
- Publication Type
- Journal Article
- Year of Publication
- 2022
- Journal
- Physical Review B
- Volume
- 105
- Date Published
- 03/2022