Non-Hermitian Fermi-Dirac Distribution in Persistent Current Transport.

Autor:	Shen PX; International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02668 Warsaw, Poland.; Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China., Lu Z; Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing 100084, China., Lado JL; Department of Applied Physics, Aalto University, FI-00076 Aalto, Espoo, Finland., Trif M; International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02668 Warsaw, Poland.
Jazyk:	angličtina
Zdroj:	Physical review letters [Phys Rev Lett] 2024 Aug 23; Vol. 133 (8), pp. 086301.
DOI:	10.1103/PhysRevLett.133.086301
Abstrakt:	Persistent currents circulate continuously without requiring external power sources. Here, we extend their theory to include dissipation within the framework of non-Hermitian quantum Hamiltonians. Using Green's function formalism, we introduce a non-Hermitian Fermi-Dirac distribution and derive an analytical expression for the persistent current that relies solely on the complex spectrum. We apply our formula to two dissipative models supporting persistent currents: (i) a phase-biased superconducting-normal-superconducting junction; (ii) a normal ring threaded by a magnetic flux. We show that the persistent currents in both systems exhibit no anomalies at any emergent exceptional points, whose signatures are only discernible in the current susceptibility. We validate our findings by exact diagonalization and extend them to account for finite temperatures and interaction effects. Our formalism offers a general framework for computing quantum many-body observables of non-Hermitian systems in equilibrium, with potential extensions to nonequilibrium scenarios.
Databáze:	MEDLINE
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