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Efficient compression of the environment of an open quantum system

Research output: Contribution to journalArticle

Original languageEnglish
Pages (from-to)165107
JournalPhysical Review B (Condensed Matter and Materials Physics)
Volume102
Accepted/In press14 Sep 2020
Published6 Oct 2020

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    main.pdf, 492 KB, application/pdf

    Uploaded date:02 Oct 2020

    Version:Accepted author manuscript

King's Authors

Abstract

In order to simulate open quantum systems, many approaches (such as Hamiltonian-based solvers in dynamical mean-field theory) aim for a reproduction of a desired environment spectral density in terms of a discrete set of bath states, mimicking the open system as a larger closed problem. Existing strategies to find a compressed representation of the environment for this purpose can be numerically demanding, or lack the compactness and systematic improvability required for an accurate description of the system propagator. We propose a method in which bath orbitals are constructed explicitly by an algebraic construction based on the Schmidt-decomposition of response wave functions, efficiently and systematically compressing the description of the full environment. These resulting bath orbitals are designed to directly reproduce the system Green’s function, not hybridization, which allows for consideration of the relevant system energy scales to optimally model. This results in an accurate and efficient truncation of the environment, with applications in a wide range of numerical simulations of open quantum systems.

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