Negativity-mutual information conversion and coherence in two-coupled harmonic oscillators

Abstract

Quantum information is a common topic of research in many areas of quantum physics, such as quantum communication and quantum computation, as well as quantum thermodynamics. It can be encoded in discrete or continuous variable systems, with the appropriated formalism to treat it generally depending on the quantum system to be chosen. For continuous variable systems, it is convenient to employ a quasi-probability function to represent quantum states and non-classical signatures. The Wigner function is a special quasi-probability function because it allows to describe a quantum system in the phase space very similar to the classical one. In this work we consider some informational aspects of two-mode continuous-variables systems. In particular we illustrate how the mutual information may be useful to transfer the non-Gaussianity property between two states. Moreover, the coherence of a Gaussian state is studied when the system is coupled to a thermal reservoir but also with an extra single-mode Gaussian state. Our results may be, in principle, investigated in trapped ions setups, where the two-mode system can be encoded in the vibrational modes of the ion.