Non-Hermitian Fermi-Dirac Distribution in Persistent Current Transport

Autor: Shen, Pei-Xin, Lu, Zhide, Lado, Jose L., Trif, Mircea
Rok vydání: 2024
Předmět:
Zdroj: Phys. Rev. Lett. 133, 086301 (2024)
Druh dokumentu: Working Paper
DOI: 10.1103/PhysRevLett.133.086301
Popis: 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 non-equilibrium scenarios.
Comment: 5+9 pages, 4+5 figures, published in Phys. Rev. Lett. with Editors' Suggestion
Databáze: arXiv