Series expansions in closed and open quantum many-body systems with multiple quasiparticle types

Lenke L, Schellenberger A, Schmidt KP (2023)

Publication Type: Journal article

Publication year: 2023

Journal

Physical Review A American Physical Society

Book Volume: 108

Article Number: 013323

Journal Issue: 1

DOI: 10.1103/PhysRevA.108.013323

Abstract

The established approach of perturbative continuous unitary transformations (pCUTs) constructs effective quantum many-body Hamiltonians as perturbative series that conserve the number of one quasiparticle type. We extend the pCUT method to similarity transformations - dubbed pcst++ - allowing for multiple quasiparticle types with complex-valued energies. This enlarges the field of application to closed and open quantum many-body systems with unperturbed operators corresponding to arbitrary superimposed ladder spectra. To this end, a generalized counting operator is combined with the quasiparticle generator for open quantum systems recently introduced by Schmiedinghoff and Uhrig [G. Schmiedinghoff and G. S. Uhrig, SciPost Phys. 13, 122 (2022)2542-465310.21468/SciPostPhys.13.6.122]. The pcst++ then yields model-independent block-diagonal effective Hamiltonians and Lindbladians, allowing a linked-cluster expansion in the thermodynamic limit similar to the conventional pCUT method. We illustrate the application of the pcst++ method by discussing representative closed, open, and non-Hermitian quantum systems.

Authors with CRIS profile

Lea Lenke Sonderforschungsbereich/Transregio 306/1: Quantenkooperativität von Licht und Materie - QuCoLiMa Andreas Schellenberger Lehrstuhl für Theoretische Physik Kai Phillip Schmidt Lehrstuhl für Theoretische Physik

Additional Organisation(s)

FAU Profilzentrum Licht.Materie.Quantentechnologien (FAU LMQ) Sonderforschungsbereich/Transregio 306/1: Quantenkooperativität von Licht und Materie - QuCoLiMa

Related research project(s)

Competing interactions in strongly correlated light-matter assemblies (D03) TRR 306: Quantenkooperativität von Licht und Materie – QuCoLiMa Jan. 1, 2021 - Dec. 31, 2024

How to cite

APA:

Lenke, L., Schellenberger, A., & Schmidt, K.P. (2023). Series expansions in closed and open quantum many-body systems with multiple quasiparticle types. Physical Review A, 108(1). https://doi.org/10.1103/PhysRevA.108.013323

MLA:

Lenke, Lea, Andreas Schellenberger, and Kai Phillip Schmidt. "Series expansions in closed and open quantum many-body systems with multiple quasiparticle types." Physical Review A 108.1 (2023).

BibTeX: Download