Dynamical symmetry breaking of lambda- and vee-type three-level systems on quantization of the field modes (original) (raw)
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Pramana, 2003
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Pramana, 2008
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International Journal of Modern Physics B, 2012
The present study investigates the interaction of an equidistant three-level atom and a single-mode cavity field that has been initially prepared in a generalized coherent state. The atom–field interaction is considered to be, in general, intensity-dependent. We suppose that the nonlinearity of the initial generalized coherent state of the field and the intensity-dependent coupling between atom and field are distinctly chosen. Interestingly, an exact analytical solution for the time evolution of the state of atom–field system can be found in this general regime in terms of the nonlinearity functions. Finally, the presented formalism has been applied to a few known physical systems such as Gilmore–Perelomov and Barut–Girardello coherent states of SU(1,1) group, as well as a few special cases of interest. Mean photon number and atomic population inversion will be calculated, in addition to investigating particular non-classicality features such as revivals, sub-Poissonian statistics a...
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Quantum Phase Properties in Collective Three-Level V-Type System with Diamagnetic Term
International Journal of Theoretical Physics, 2019
In this paper, we present a rigorous investigation of the quantum phase transitions (QPTs) for a model which describes the degenerate collective regime of a three-level Vconfiguration atoms Bose-Einstein condensate (BEC). We consider that the three-level atoms of a BEC coupled to an optical resonator (cavity) with high finesse in the presence of a diamagnetic term, i. e., a system of N-identical three-level atoms interacting with a one-mode quantized electromagnetic cavity field. Also, the different components of this system are labeled by the different phase factors. By using the Glauber's coherent states for the field, we calculate the free energy and study the finite-temperature phase transition for this model in the thermodynamic limit (N → ∞). Also, the potential energy surfaces constructed by taking the expectation value with respect to the direct product for a test state a direct product of coherent Heisenberg-Weyl HW(1)-states (for the electromagnetic field), and U(3) (for the atomic field, i. e., matter contribution) coherent states. Moreover, the scaled ground-state energy is obtained by taking the expectation value of an effective Hamiltonian in the framework of the mean-field approach. In the thermodynamic limit, the energy surface takes a simple form for a direct description of the phase transitions. The relation between the QPTs and the symmetry physics are established and the QPTs for this model are investigated numerically. The properties of both stability and the equilibrium are calculated using the catastrophe theory. We notice that the second-order phase transitions (superradiant (SR)) with multi-level systems might be achievable in a wide range of physical systems, especially those where it is possible to engineer the spectra and oscillator strengths.
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Nonlinear spectroscopy of a three level atom strongly interacting with a quantized cavity mode
arXiv (Cornell University), 2019
We present detailed numerical simulations of semiclassical and quantum spectra of a cavity quantum electrodynamics system consisting of a single three-level atom in Λ-configuration with one of its transitions strongly interacting with a quantized cavity mode while the other is driven by a coherent classical field. After deriving the equations of motion for the expected values of the system operators from the master equation, we compute numerically the semiclassical and quantum spectra of the system under various levels of external driving field strengths. In the semiclassical approach we neglect the quantum correlations between cavity and atomic operators, while we make no such assumption in the fully quantum approach. We show that, under sufficiently weak driving field conditions, the semiclassical and fully quantum mechanical approaches result in identical spectra. However at higher driving field intensities, the two approaches yield starkly different results: The fully quantum mechanical approach results in multiphoton spectrum with well-defined structure while the semiclassical results in a bistable spectrum. Our results also reveal that the Raman transition mediated by the dark state of the system has a complex structure that depends on the manner in which the system is probed.
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