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Nonequilibrium dynamics and transport in Holstein models

December 13, 2023 @ 09:00 - 09:30 CET

F. Heidrich-Meisner1

1Institut für Theoretische Physik, Georg-August-Universität Göttingen, Germnay

Understanding the properties of real materials requires the incorporation of multiple degrees of freedom into the theoretical modeling. In this research, we focus on the coupling of electrons to phonons. We developed a comprehensive matrix-product-states based schemes that allows to compute spectral functions [1], optical conductivity [2] and thermal conductivity [3] of one-dimensional Holstein chains, both for the polaron case and half filling, and at finite temperatures. These techniques work well in the small-polaron regime and in intermediate regimes where phonon frequency, electron-phonon coupling and elecronic hopping matrix elements are of the same scale.

In order to access the adiabatic regime of phonon frequencies much smaller than the electronic bandwidth, we combine matrix-product-state and Krylov-space methods with the multritrajectory Ehrenfest technique, called MPS-MTE and Lanczos-MTE [4]. The latter treats phonons classically and samples over initiial conditions set by the phonons‘ initial quantum state. The resulting hybrid techniqes rely on a propagation of electronic many-body states that depend on the time-dependent classical coordinates and momenta. We verify the correct implemenation by studying the decay of charge-density wave order analyzed in [5] and then apply the MPS-MTE method to the problem of a many-body localized system coupled to classical phonons. We observe a delocalization induced by this coupling.

This research was suported by the DFG (Deutsche Forschungsgemeinschaft) via CRC 1073.

  1. D. Jansen, J. Bonča, and F. Heidrich-Meisner Phys. Rev. B 102, 165155 (2020)
  2. D. Jansen, J. Bonča, and F. Heidrich-Meisner, Phys. Rev. B 106, 155129 (2022)
  3. D. Jansen and F. Heidrich-Meisner, Phys. Rev. B 108, L081114 (2023)
  4. H. Menzler, S. Mondal, and F. Heidrich-Meisner, in preparation.
  5. M. Ten Brink et al. J. Chem. Phys. 156, 234109 (2022)


December 13, 2023
09:00 - 09:30 CET
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