The Experts below are selected from a list of 252 Experts worldwide ranked by ideXlab platform
M K Tavassoly - One of the best experts on this subject based on the ideXlab platform.
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quantum dynamics of a bec interacting with a single mode Quantized Field in the presence of interatom collisions
Physics Letters A, 2016Co-Authors: Ebrahim Ghasemian, M K TavassolyAbstract:Abstract In this paper, we consider a model in which N two-level atoms in a Bose–Einstein condensate (BEC) interact with a single-mode Quantized laser Field. Our goal is to investigate the quantum dynamics of atoms in the BEC in the presence of interatom interactions. To achieve the purpose, at first, using the collective angular momentum operators, we try to reduce the dynamical Hamiltonian of the system to a well-known Jaynes–Cummings like model (JCM). We also use the Dicke model to construct the state of atomic subsystem, by which the analytical solution of the system may be obtained. Then, we analyze the atomic population inversion, the degree of entanglement between the “atoms in BEC” and the “Field” as well as the Mandel parameter. Numerical results show that, the atomic population inversion, atom-Field entanglement and quantum statistics of photons are very sensitive to the evolved parameters in the model (and so can be well-adjusted), such as the number of atoms in BEC, the intensity of initial Field, the interatom coupling constant and detuning. To investigate the entanglement properties, we pay attention to the entropy and linear entropy. It is shown that, oscillations in the two entropy criteria may be seen, with some maxima of entanglement at some moments of time. Finally, looking for the quantum statistics, we evaluate the Mandel parameter, by which we demonstrate the sub-Poissonian statistics and so the nonclassical characteristics of the Field state of system. Collapse-revival phenomenon, which is a distinguishable nonclassical characteristic of the system, can be apparently observed in the atomic population inversion and the Mandel parameter.
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generation and nonclassicality of entangled states via the interaction of two three level atoms with a Quantized cavity Field assisted by a driving external classical Field
arXiv: Quantum Physics, 2015Co-Authors: H R Baghshahi, M K Tavassoly, Seyed Javad AkhtarshenasAbstract:The interaction of two identical three-level atoms of the types $V$, $\Xi$ and $\Lambda$ with a Quantized cavity Field as well as a driving external classical Field is studied. Under two certain unitary transformations, the system is converted to a typical form of the Jaynes-Cummings model for two three-level atoms. The exact analytical solutions of the wave function for different considered atom-Field systems are exactly obtained with the help of the Laplace transform technique, when the atoms are initially prepared in the topmost excited state and the Quantized Field is in a coherent state. In order to examine the nonclassicality features of the deduced states, the dynamics of the entanglement between subsystems is discussed via two well-known measures, namely, von Neumann entropy of the reduced state and negativity. In addition, we pay attention to the temporal behaviour of quantum statistics of the photons of the Field and squeezing phenomenon. Meanwhile, the influence of the external classical Field on the latter physical quantities is analyzed in detail. The results show that the mentioned quantities can be sensitively controlled via the external classical Field. Also, numerical computations imply the fact that the nonclassicality features in $\Xi$-type three-level atomic system is more visible than the other two configurations. In addition, it is shown that in the particular case of $\Lambda$-type atomic system, the rank of the reduced density matrix of the three-level atoms is no larger than three, so that negativity fully captures the entanglement of this system and that such entanglement is distillable.
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generation of su 1 1 and su 2 entangled states in a Quantized cavity Field by strong driving assisted classical Field approach
Laser Physics, 2015Co-Authors: R. Daneshmand, M K TavassolyAbstract:Following the approach of Solano et al (2003 Phys. Rev. Lett. 90 027903) we propose a scheme for a generation of a few classes of entangled (nonlinear) coherent states. To achieve this purpose, the interaction of a spatially narrow collection of two-level atoms with a Quantized Field in a high-Q factor cavity in the presence of a strong-driving classical Field is studied. We perform appropriate Hamiltonians describing the atom-Field interaction by focusing on two particular forms of intensity-dependent functions which are directly related to su(1, 1) and su(2) Lie algebras. It is shown that the dynamical evolution of the considered systems can generate bipartite, tripartite (nonlinear) and more complicated entangled states corresponding to the mentioned groups depending on the number of atoms in the cavity. In the processes of the abovementioned generation schemes, even and odd nonlinear coherent states are produced. In the end, in a particular circumstance with the two-mode Quantized Field we can turn easily from Jaynes–Cummings to anti-Jaynes–Cummings interactions which brings us to the maximally entangled number state. Finally, to quantify the degree of entanglement of the produced states, the measures of von Neumann and linear entropies are applied.
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dynamical properties of a trapped two level ion interacting with a single mode Quantized Field in the nonlinear regime
Journal of Modern Optics, 2015Co-Authors: Navid Yazdanpanah, M K TavassolyAbstract:Following the path of Bužek et al. in [Phys. Rev. A 56 2352 1997], we investigate the full intensity-dependent interaction between a motional two-level ion which is trapped in a f-deformed oscillator (so possessing vibrational modes too) with a single-mode nonlinear Quantized Field in the Lamb-Dicke limit. After finding the explicit form of the entire ion-Field state vector in a general framework, we particularly restrict ourselves to an appropriate nonlinearity function (describing intensity-dependent interaction) corresponding to the center-of-mass motion of a trapped ion which explicitly depends on the Lamb-Dicke parameter as well as another well-known nonlinearity function in the form n. Then, we evaluate the effects of two different initial Quantized Field states as well as the considered nonlinearity function (via varying the Lamb-Dicke parameter) on a few physical properties of the system. For this purpose, we pay attention to the amount of entanglement, mean number of vibrational quanta (phonons),...
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quantum entanglement and position momentum entropic squeezing of a moving lambda type three level atom interacting with a single mode Quantized Field with intensity dependent coupling
Journal of Physics B, 2013Co-Authors: Mohammad Javad Faghihi, M K TavassolyAbstract:In this paper, we study the interaction between a moving Λ-type three-level atom and a single-mode cavity Field in the presence of intensity-dependent atom–Field coupling. After obtaining the state vector of the entire system explicitly, we study the nonclassical features of the system such as quantum entanglement, position–momentum entropic squeezing, quadrature squeezing and sub-Poissonian statistics. According to the obtained numerical results we illustrate that the squeezed period, the duration of entropy squeezing and the maximal squeezing can be controlled by choosing the appropriate nonlinearity function together with entering the atomic motion effect by the suitable selection of the Field-mode structure parameter. Also, the atomic motion, as well as the nonlinearity function, leads to the oscillatory behaviour of the degree of entanglement between the atom and Field.
X X Yi - One of the best experts on this subject based on the ideXlab platform.
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response of two band systems to a single mode Quantized Field
Physical Review E, 2016Co-Authors: H Z Shen, W Wang, X X YiAbstract:: The response of topological insulators (TIs) to an external weakly classical Field can be expressed in terms of Kubo formula, which predicts Quantized Hall conductivity of the quantum Hall family. The response of TIs to a single-mode Quantized Field, however, remains unexplored. In this work, we take the quantum nature of the external Field into account and define a Hall conductance to characterize the linear response of a two-band system to the Quantized Field. The theory is then applied to topological insulators. Comparisons with the traditional Hall conductance are presented and discussed.
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Hall conductance of two-band systems in a Quantized Field
arXiv: Mesoscale and Nanoscale Physics, 2015Co-Authors: H Z Shen, X X YiAbstract:Kubo formula gives a linear response of a quantum system to external Fields, which are classical and weak with respect to the energy of the system. In this work, we take the quantum nature of the external Field into account, and define a Hall conductance to characterize the linear response of a two-band system to the Quantized Field. The theory is then applied to topological insulators. Comparisons with the traditional Hall conductance are presented and discussed.
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berry s phase with Quantized Field driving effects of intersubsystem coupling
Physical Review A, 2004Co-Authors: L C Wang, X X YiAbstract:The effect of inter-subsystem couplings on the Berry phase of a composite system as well as that of its subsystem is investigated in this paper. We analyze two coupled spin-$\frac 1 2 $ particles with one driven by a Quantized Field as an example, the pure state geometric phase of the composite system as well as the mixed state geometric phase for the subsystem is calculated and discussed.
Mohammad Javad Faghihi - One of the best experts on this subject based on the ideXlab platform.
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quantum entanglement and position momentum entropic squeezing of a moving lambda type three level atom interacting with a single mode Quantized Field with intensity dependent coupling
Journal of Physics B, 2013Co-Authors: Mohammad Javad Faghihi, M K TavassolyAbstract:In this paper, we study the interaction between a moving Λ-type three-level atom and a single-mode cavity Field in the presence of intensity-dependent atom–Field coupling. After obtaining the state vector of the entire system explicitly, we study the nonclassical features of the system such as quantum entanglement, position–momentum entropic squeezing, quadrature squeezing and sub-Poissonian statistics. According to the obtained numerical results we illustrate that the squeezed period, the duration of entropy squeezing and the maximal squeezing can be controlled by choosing the appropriate nonlinearity function together with entering the atomic motion effect by the suitable selection of the Field-mode structure parameter. Also, the atomic motion, as well as the nonlinearity function, leads to the oscillatory behaviour of the degree of entanglement between the atom and Field.
Peter Foldi - One of the best experts on this subject based on the ideXlab platform.
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high order harmonic generation as induced by a Quantized Field phase space picture
Physical Review A, 2020Co-Authors: Akos Gombkotő, S Varro, Peter Mati, Peter FoldiAbstract:The interaction of matter with a Quantized electromagnetic mode is considered. Representing a strong exciting Field, the mode is assumed to contain a large number of photons. As a result, the material response is highly nonlinear: the completely Quantized description results in generation of high harmonics. In order to understand the essence of the physical processes that are involved, we consider a finite dimensional model for the material system. Using an appropriate description in phase space, this approach leads to a transparent picture showing that the interaction splits the initial, exciting coherent state into parts, and the rapid change of the populations of these parts (that are coherent states themselves) results in the generation of high-order harmonics as secondary radiation. The method we use is an application of the discrete lattice of coherent states that was introduced by J. von Neumann.
Zou Jian - One of the best experts on this subject based on the ideXlab platform.
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Entanglement between charge qubit and Quantized Field
2006Co-Authors: Li Zhao-xin, Zou Jian, Cai Jin-fangAbstract:We investigate time evolution of the entanglement between charge qubit initially in mixed states and Quantized Field. By calculating the concurrence lower bound, we study the effect of initial mixedness λ and detuning Δ on the entanglement of the system. In the case of weak Field, the degree of entanglement for charge qubit being initially in excited state is much larger than that for charge qubit being initially in ground state, and detuning Δ can efficiently reduce the entanglement. But in the case of strong Field, the time evolution of the entanglement is about the same for charge qubit being initially in excited and ground states, the more mixed the initial state of charge qubit is prepared, the weaker the entanglement is, and Δ has less effect on the entanglement than in the case of weak Field.
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entanglement of two superconducting charge qubits induced by Quantized radiation Field
Communications in Theoretical Physics, 2004Co-Authors: Zou Jian, Li QianshuAbstract:We consider two superconducting charge qubits coupled by a single-mode Quantized Field. We suppose that the two superconducting charge qubits be initially prepared in the mixed and separable state. As time evolves, we will investigate the entanglement between two superconducting charge qubits induced by the Quantized Field.
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Collapse and revival of a single-Cooper-pair box in a single-mode Quantized Field
Chinese Physics, 2003Co-Authors: Zou JianAbstract:We study the quantum dynamics of a single-Cooper-pair box biased by a classical voltage and also irradiated by a single-mode Quantized Field. We demonstrate that under weak damping of the Quantized Field, the collapse-revival phenomena can exist in this system and the oscillations of the collapse and revival depend sensitively on the initial state of the single-mode Quantized Field and the damping rate κ. We also demonstrate that this system can show the beats phenomena.
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Dynamic behaviour of a single-Cooper-pair box in a single-mode Quantized Field with dissipation
Chinese Physics, 2002Co-Authors: Zou JianAbstract:We study the quantum dynamics of a single-Cooper-pair box biased by a classical voltage and also irradiated by a single-mode Quantized Field. We demonstrate that under the weak damping, the collapse-revival phenomena can exist in this system. We also demonstrate that the revivals of oscillations are sensitive to the initial coherent Field and the damping rate of the single-mode Quantized Field.
