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Published on: November 24, 2021
Liouvillian exceptional points of an open driven two-level system
Nikhil Seshadri1, Anqi Li2, Michael Galperin2
1Harvard University, Cambridge, Massachusetts 02138, USA.
Abstract:
We study the applicability of the Liouvillian exceptional points (LEPs) approach to nanoscale open quantum systems. A generic model of the driven two-level system in a thermal environment is analyzed within the nonequilibrium Green's function (NEGF) and Bloch quantum master equation formulations. We derive the latter starting from the exact NEGF Dyson equations and highlight the qualitative limitations of the LEP treatment by examining the approximations employed in its derivation. We find that the non-Markov character of evolution in open quantum systems does not allow for the introduction of the concept of exceptional points for a description of their dynamics. Theoretical analysis is illustrated with numerical simulations.
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