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Liouvillian exceptional points of an open driven two-level system
Nikhil Seshadri1, Anqi Li2, Michael Galperin2
1Harvard University, Cambridge, Massachusetts 02138, USA.
The Journal of Chemical Physics
|January 30, 2024
Summary
The Liouvillian exceptional points (LEPs) approach is not suitable for describing nanoscale open quantum systems due to their non-Markovian dynamics. This study highlights the limitations of LEPs in accurately modeling these complex quantum systems.
Area of Science:
- Quantum physics
- Nanoscale systems
- Open quantum systems
Background:
- The Liouvillian exceptional points (LEPs) approach is a theoretical framework used in quantum mechanics.
- Nanoscale open quantum systems are complex systems interacting with their environment.
- Understanding the dynamics of these systems is crucial for quantum technologies.
Purpose of the Study:
- To investigate the applicability of the Liouvillian exceptional points (LEPs) approach to nanoscale open quantum systems.
- To analyze a driven two-level system in a thermal environment using established quantum formulations.
- To identify the limitations of the LEP treatment in describing the dynamics of open quantum systems.
Main Methods:
- Analysis of a driven two-level system model.
- Utilizing nonequilibrium Green's function (NEGF) and Bloch quantum master equation formulations.
- Derivation of the Bloch quantum master equation from NEGF Dyson equations.
- Examination of approximations within the LEP derivation.
- Numerical simulations to illustrate theoretical findings.
Main Results:
- The non-Markov character of evolution in open quantum systems was identified as a key challenge.
- The study found that the non-Markovian nature prevents the direct application of exceptional points for describing system dynamics.
- Qualitative limitations of the LEP approach were highlighted.
Conclusions:
- The Liouvillian exceptional points (LEPs) approach is not universally applicable to nanoscale open quantum systems.
- The non-Markovian dynamics inherent in these systems fundamentally restrict the utility of the LEP concept.
- Further development of theoretical frameworks is needed for accurate modeling.
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