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Quantum correlations between two oscillators connected by a time-dependent coupling
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| Author(s): |
Thales Figueiredo Roque
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Física Gleb Wataghin |
| Defense date: | 2012-09-08 |
| Examining board members: |
José Antonio Roversi;
Celso Jorge Villas Boas;
Kyoko Furuya
|
| Advisor: | José Antonio Roversi |
| Abstract | |
In this work we analise the dinamics of quantum correlations in a system composed by two harmonic oscillators in contact with a common heat bath and coupled with each other by a time dependent coupling. The heat bath is modeled according to the Caldeira-Leggett model and both the path integral and the master equation approaches are used to study the system in the Markovian and in the non-Markovian regime. The Hamiltonian that describes the system is bilinear in the field opperators, this means that if we prepare the system in a Gaussian state, it remains in a Gaussian state indefinitely. For a Gaussian state all the information about the quantum correlations is in the covariance matrix s and we are able to calculate the Logarithmic Negativity as a measure of the systems¿ entanglement and the Gaussian discord as an approximantion to the usual quantum discord, that is a measure of quantum correlations. We have shown that in some circunstances we can observe the survival of quantum correlations and entanglement, even at very high temperatures. This survival has close relationship with the stability of the system¿s equation of motion. As quantum correlations are the main feature of quantum mechanics, this sugests that this particular coupling between the oscillators can reduce the decoherence effects induced by the interaction with the heat bath (AU) | |
| FAPESP's process: | 11/04521-0 - Classical and quantum correlations in a system composed by two harmonic oscillators with a time-dependent coupling and in contact with a thermal reservoir |
| Grantee: | Thales Figueiredo Roque |
| Support Opportunities: | Scholarships in Brazil - Master |