Quantum Phase Properties in Collective Three-Level V-Type System with Diamagnetic Term (original) (raw)
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International Journal of Theoretical Physics, 2017
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Journal of Russian Laser Research, 2018
We present a two-level atomic Bose-Einstein condensate (BEC) with dispersion, which is coupled to a high-finesse optical cavity. We call this model the extended Jaynes-Cummings-Dicke (JC-Dicke) model and introduce an effective Hamiltonian for this system. From the direct product of Heisenberg-Weyl (HW) coherent states for the field and U (2) coherent states for the matter, we obtain the potential energy surface of the system. Within the framework of the mean-field approach, we evaluate the variational energy as the expectation value of the Hamiltonian for the considered state. We investigate numerically the quantum phase transition and the Berry phase for this system. We find the influence of the atom-atom interactions on the quantum phase transition point and obtain a new phase transition occurring when the microwave amplitude changes. Furthermore, we observe that the coherent atoms not only shift the phase transition point but also affect the macroscopic excitations in the superradiant phase.
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Bose-Einstein condensates present to us the opportunity to probe into the atomic interactions that govern a macroscopic quantum mechanical system. The degenerate hyperfine manifold in the bosonic atoms splits in the presence of an external B-field; radio-frequency induced coupling releases experimentally-attainable knowledge about the Zeeman manifold in 87 Rb. The purpose of this study is to investigate quantum dynamics in two and three-component Bose-Einstein condensate (BEC) systems. We start with a theoretical analysis of Josephson tunneling dynamics between identical BECs trapped in a double potential well, paying particular attention to the non-linear self-trapping e↵ect observed as a consequence of the intra-well interaction. We present a model for the non-equilibrium dynamics in a two-level system and introduce the Rabi oscillations. This is followed by a numerical and experimental investigation of Rabi oscillations in a three-level 87 Rb BEC between the F = 1 hyperfine level spin states m F 2 { 1, 0, 1}. The relation between the observed total Rabi frequency, ⌦ R and the detuning , along with its e↵ect on the BEC population dynamics is explored. Finally, we explore the possible suspects for the shift of the resonance at strong Rabi frequencies ⌦.