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arXiv · 1303.5815

Qubit-mediated energy transfer between thermal reservoirs: beyond Markovian Master equation

D. Segal
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Abstract

We study qubit-mediated energy transfer between two electron reservoirs by adopting a numerically-exact influence functional path-integral method. This non-perturbative technique allows us to study the system's dynamics beyond the weak coupling limit. Our simulations for the energy current indicate that perturbative-Markovian Master equation predictions significantly deviate from exact numerical results already at intermediate coupling, $\pi \rho \alpha_{j,j'}\gtrsim 0.4$, where $\rho$ is the metal (Fermi sea) density of states, taken as a constant, and $\alpha_{j,j'}$ is the scattering potential energy of electrons, between the $j$ and $j'$ states. Markovian Master equation techniques should be therefore used with caution beyond the strictly weak subsystem-bath coupling limit, especially when a quantitative knowledge of transport characteristics is desired.

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D. Segal. 2013-03-23. Qubit-mediated energy transfer between thermal reservoirs: beyond Markovian Master equation. https://doi.org/10.1103/physrevb.87.195436

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