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

• URL: http://arxiv.org/abs/2412.10020v1
• Date: Fri, 13 Dec 2024 10:01:18 GMT
• Title: Gaussian quantum Markov semigroups on finitely many modes admitting a normal invariant state
• Abstract summary: Gaussian quantum Markov semigroups (GQMSs) are of fundamental importance in modelling the evolution of several quantum systems.<n>We completely characterize those GQMSs that admit a normal invariant state and we provide a description of the set of normal invariant states.<n>We study the behavior of such semigroups for long times: firstly, we clarify the relationship between the decoherence-free subalgebra and the spectrum of $mathbfZ$.
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• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: 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 $\mathbf{\zeta}$. 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.

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