Examinando por Autor "Correa, Luis A"

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Asymptotic discord and entanglement of nonresonant harmonic oscillators under weak and strong dissipation
(American Physical Society, 2012-07-20) Valido, Antonio A; Alonso, Daniel; Correa, Luis A
In this work, we calculate the exact asymptotic quantum correlations between two interacting nonresonant harmonic oscillators in a common Ohmic bath. We derive analytical formulas for the covariances, fully describing any Gaussian stationary state of the system, and use them to study discord and entanglement in the strong- and weak-dissipation regimes. We discuss the rich structure of the discord of the stationary separable states arising in the strong-dissipation regime. Also under strong dissipation, when the modes are not mechanically coupled, these may entangle only through their interaction with the common environment. Interestingly enough, this stationary entanglement assisted by dissipation is only present within a finite band of frequencies and increases with the dissipation rate. Robust entanglement between detuned oscillators is also observed at low temperature.
Gaussian tripartite entanglement out of equilibrium
(American Physical Society, 2013-07-11) Valido, Antonio A; Alonso, Daniel; Correa, Luis A
The stationary multipartite entanglement between three interacting harmonic oscillators subjected to decoherence is analyzed in the largely unexplored nonequilibrium strong dissipation regime. We compute the exact asymptotic Gaussian state of the system and elucidate its separability properties, qualitatively assessing the regions of the space of parameters in which fully inseparable states are generated. Interestingly, the sharing structure of bipartite entanglement is seen to degrade as dissipation increases even for very low temperatures, at which the system approaches its ground state. We also find that establishing stationary energy currents across the harmonic chain does not correspond with the buildup of biseparable steady states, which relates instead just to the relative intensity of thermal fluctuations.