Controle da não Markovianidade em sistemas quânticas abertos
Rafael Bruno Barbosa Lima
Open quantum systems have been aim of several theoretical and experimental studies over the last years.In particular, research related to non-Markovianity and how it influences the dynamics of the system has become relatively important, because this way we can have the return the initial quantum characteristics present in the system.In this thesis two related works were developed about the influence of non-Markovianity in open quantum systems.In the first, it was used a one qubit system in contact with a bosonic reservoir and also under the influence of a classic stochastic pumping, thus generating an effective coupling of the system with the stochastic noise and the thermal reservoir.Thus, it was investigated how the dynamics of the qubit is modified through the production of non-Markovianity in the system due to the effective coupling and also how the mean system energy, with and without pumping, behaves in both Markovian and non-Markovian regime.Additionally, an analysis of non-Markovianity production was performed using exponential, Gaussian and power law stochastic noises.Applying the Andersson, Cresser, Hall and Li (ACHL) measure, it was possible to make a comparison of how much non-Markovianity was produced for each stochastic noise.In the second work, a study was performed on how it is possible to generate the transition between Markovian to non-Markovian regimes through the control of the spin-lattice relaxation time of an ancillary qubit, which acts as an environment.The decoherence of the system was simulated through the formulation of quantum channels.In addition, it was discussed how the relaxation mechanism is modified by the action of an external magnetic field.Finally, an experimental demonstration of the model is presented and the experimental data were compared with the theoretically simulated ones.
•Apr 3, 2020•0 citations