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arXiv · 1806.02570

Quantum Boltzmann equation for strongly correlated systems: comparison to dynamical mean field theory

Michael Wais·Martin Eckstein·Roland Fischer·Philipp Werner·Marco Battiato·Karsten Held
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Abstract

We investigate the potential of a quantum Boltzmann equation without momentum conservation for description of strongly correlated electron systems out of equilibrium. In a spirit similar to dynamical mean field theory (DMFT), the momentum conservation of the electron-electron scattering is neglected, which yields a time-dependent occupation function for the equilibrium spectral function, even in cases where well-defined quasiparticles do not exist. The main assumption of this method is that the spectral function remains sufficiently rigid under the non-equilibrium evolution. We compare the result of the quantum Boltzmann equation to non-equilibrium DMFT simulations for the case of photo-carrier relaxation in Mott insulators, where processes on very different timescales emerge, i.e., impact ionization, intra-Hubbard-band thermalization, and full thermalization. Since quantum Boltzmann simulations without momentum conservation are computationally cheaper than non-equilibrium DMFT, this method allows the simulation of more complicated systems or devices, and to access much longer times.

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Michael Wais, Martin Eckstein, Roland Fischer, Philipp Werner, Marco Battiato, Karsten Held. 2018-06-07. Quantum Boltzmann equation for strongly correlated systems: comparison to dynamical mean field theory. https://doi.org/10.1103/physrevb.98.134312

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