Gaussian quantum Markov semigroups on finitely many modes admitting a normal invariant state

Fuente: arXiv
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Main Authors: Girotti, Federico, Poletti, Damiano
Format: Preprint
Published: 2024
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_version_ 1866910743866114048
author Girotti, Federico
Poletti, Damiano
author_facet Girotti, Federico
Poletti, Damiano
contents Gaussian quantum Markov semigroups (GQMSs) are of fundamental importance in modelling the evolution of several quantum systems. Moreover, they represent the noncommutative generalization of classical Orsntein-Uhlenbeck semigroups; analogously to the classical case, GQMSs are uniquely determined by a "drift" matrix $\mathbf{Z}$ and a "diffusion" matrix $\mathbf{C}$, together with a displacement vector $\mathbfζ$. In this work, we completely characterize those GQMSs that admit a normal invariant state and we provide a description of the set of normal invariant states; as a side result, we are able to characterize quadratic Hamiltonians admitting a ground state. Moreover, we study the behavior of such semigroups for long times: firstly, we clarify the relationship between the decoherence-free subalgebra and the spectrum of $\mathbf{Z}$. Then, we prove that environment-induced decoherence takes place and that the dynamics approaches an Hamiltonian closed evolution for long times; we are also able to determine the speed at which this happens. Finally, we study convergence of ergodic means and recurrence and transience of the semigroup.
format Preprint
id arxiv_https___arxiv_org_abs_2412_10020
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Gaussian quantum Markov semigroups on finitely many modes admitting a normal invariant state
Girotti, Federico
Poletti, Damiano
Functional Analysis
Quantum Physics
46L55, 37L40, 81V73
Gaussian quantum Markov semigroups (GQMSs) are of fundamental importance in modelling the evolution of several quantum systems. Moreover, they represent the noncommutative generalization of classical Orsntein-Uhlenbeck semigroups; analogously to the classical case, GQMSs are uniquely determined by a "drift" matrix $\mathbf{Z}$ and a "diffusion" matrix $\mathbf{C}$, together with a displacement vector $\mathbfζ$. In this work, we completely characterize those GQMSs that admit a normal invariant state and we provide a description of the set of normal invariant states; as a side result, we are able to characterize quadratic Hamiltonians admitting a ground state. Moreover, we study the behavior of such semigroups for long times: firstly, we clarify the relationship between the decoherence-free subalgebra and the spectrum of $\mathbf{Z}$. Then, we prove that environment-induced decoherence takes place and that the dynamics approaches an Hamiltonian closed evolution for long times; we are also able to determine the speed at which this happens. Finally, we study convergence of ergodic means and recurrence and transience of the semigroup.
title Gaussian quantum Markov semigroups on finitely many modes admitting a normal invariant state
topic Functional Analysis
Quantum Physics
46L55, 37L40, 81V73
url https://arxiv.org/abs/2412.10020