Volume 139, Number 3, August 2022
|Number of page(s)
|Condensed matter and materials physics
|28 July 2022
Coupling function from bath density of states
1 University of Potsdam, Institut für Physik und Astronomie - 14476 Potsdam, Germany
2 Department of Physics and Astronomy, University of Exeter - Stocker Road, Exeter EX4 4QL, UK
Received: 17 December 2021
Accepted: 22 June 2022
Modelling of an open quantum system requires knowledge of parameters that specify how it couples to its environment. However, beyond relaxation rates, realistic parameters for specific environments and materials are rarely known. Here we present a method of inferring the coupling between a generic system and its bosonic (e.g., phononic) environment from the experimentally measurable density of states (DOS). With it we confirm that the DOS of the well-known Debye model for three-dimensional solids is physically equivalent to choosing an Ohmic bath. We further match a real phonon DOS to a series of Lorentzian coupling functions, allowing us to determine coupling parameters for gold, yttrium iron garnet (YIG) and iron as examples. The results illustrate how to obtain material-specific dynamical properties, such as memory kernels. The proposed method opens the door to more accurate modelling of relaxation dynamics, for example for phonon-dominated spin damping in magnetic materials.
© 2022 The author(s)
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