Speaker
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Mircea TRIF
Mircea TRIF : Non-Hermitian Fermi-Dirac distribution in persistent current transport
Mircea TRIF, International Research Centre MagTop, Polish Academy of Sciences, Warsaw, Poland
The resume :
I will introduce a theoretical framework for describing the persistent current transport in non-Hermitian quantum systems, building on the foundation of Hermitian superconducting-normal-superconducting junctions. To incorporate dissipation, I will employ a Green’s function formalism and show the emergence of a non-Hermitian Fermi-Dirac distribution that allows deriving an analytical expression for the persistent current solely in terms of the complex spectrum.
This formula is applied to two dissipative models: (i) a phase-biased superconducting-normal-superconducting junction, and (ii) a normal mesoscopic ring threaded by a magnetic flux. I will demonstrate that the persistent currents in both systems exhibit no anomalies at emergent exceptional points, whose signatures instead become apparent in the current-current susceptibility — a dynamical quantity. These results, validated by exact diagonalization, are further extended to include finite temperature and interaction effects.
I will conclude by discussing potential applications of this formalism in designing non-Hermitian devices, such as superconducting diodes, and for exploring non-equilibrium quantum transport.
Reference:
P.-X. Shen, Z. Lu, J. L. Lado, and M. Trif, Non-Hermitian Fermi-Dirac Distribution in Persistent Current Transport, Phys. Rev. Lett. 133, 086301 (2024).