Erlangen 2022 – scientific programme

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SYQC: Symposium Quantum Cooperativity of Light and Matter

SYQC 2: Quantum Cooperativity of Light and Matter - Session 2

SYQC 2.5: Talk

Thursday, March 17, 2022, 15:15–15:30, Audimax

Applying continuous unitary transformations to open quantum systems — •Lea Lenke, Matthias Mühlhauser, and Kai Phillip Schmidt — Lehrstuhl für Theoretische Physik I, Staudtstraße 7, Universität Erlangen-Nürnberg, D-91058 Erlangen, Germany

We generalize the method of continuous unitary transformations (CUTs) to certain types of open systems. In some cases -- such as gain-loss Hamiltonians -- there exists an effective description in terms of non-Hermitian Hamiltonians. For the latter we successfully apply a perturbative CUT (pCUT) to two non-Hermitian PT-symmetric quantum spin models in order to determine their low-energy physics [1]. In a next step, we aim at generalizing this method further to dissipative frustrated systems described by a Lindblad master equation.

[1] L. Lenke, M. Mühlhauser, and K. P. Schmidt, ``High-order series expansion of non-Hermitian quantum spin models'', Phys. Rev. B 104, 195137 (2021).