Exceptional points in Gaussian channels: diffusion gauging and drift-governed spectrum

Fuente: arXiv
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Auteur principal: Rodríguez, Frank Ernesto Quintela
Format: Preprint
Publié: 2026
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author Rodríguez, Frank Ernesto Quintela
author_facet Rodríguez, Frank Ernesto Quintela
contents McDonald and Clerk [Phys.\ Rev.\ Research 5, 033107 (2023)] showed that for linear open quantum systems the Liouvillian spectrum is independent of the noise strength. We first make this noise-independence principle precise in continuous time for multimode bosonic Gaussian Markov semigroups: for Hurwitz drift, a time-independent Gaussian similarity fixed by the Lyapunov equation gauges away diffusion for all times, so eigenvalues and non-diagonalizability are controlled entirely by the drift, while diffusion determines steady states and the structure of eigenoperators. We then extend the same separation to discrete time for general stable multimode bosonic Gaussian channels: for any stable Gaussian channel, we construct an explicit Gaussian similarity transformation that gauges away diffusion at the level of the channel parametrization. We illustrate the method with a single-mode squeezed-reservoir Lindbladian and with a non-Markovian family of single-mode Gaussian channels, where the exceptional-point manifolds and the associated gauging covariances can be obtained analytically.
format Preprint
id arxiv_https___arxiv_org_abs_2601_16121
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Exceptional points in Gaussian channels: diffusion gauging and drift-governed spectrum
Rodríguez, Frank Ernesto Quintela
Quantum Physics
Mathematical Physics
McDonald and Clerk [Phys.\ Rev.\ Research 5, 033107 (2023)] showed that for linear open quantum systems the Liouvillian spectrum is independent of the noise strength. We first make this noise-independence principle precise in continuous time for multimode bosonic Gaussian Markov semigroups: for Hurwitz drift, a time-independent Gaussian similarity fixed by the Lyapunov equation gauges away diffusion for all times, so eigenvalues and non-diagonalizability are controlled entirely by the drift, while diffusion determines steady states and the structure of eigenoperators. We then extend the same separation to discrete time for general stable multimode bosonic Gaussian channels: for any stable Gaussian channel, we construct an explicit Gaussian similarity transformation that gauges away diffusion at the level of the channel parametrization. We illustrate the method with a single-mode squeezed-reservoir Lindbladian and with a non-Markovian family of single-mode Gaussian channels, where the exceptional-point manifolds and the associated gauging covariances can be obtained analytically.
title Exceptional points in Gaussian channels: diffusion gauging and drift-governed spectrum
topic Quantum Physics
Mathematical Physics
url https://arxiv.org/abs/2601.16121