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Manipulation of spontaneous emission from an atom confined in three kinds of modified reservoirs has been investigated by means of an elliptically polarized laser field. Some interesting phenomena such as the multi-peak structure, extreme spectral narrowing, and cancellation of spontaneous emission can be observed by adjusting controllable system parameters. Moreover, these phenomena depend on the constructive or destructive quantum interference between multiple decay channels and which can be changed appreciably by varying the phase difference between the two circularly polarized components of the probe field. These results demonstrate the importance of an elliptically polarized laser field in controlling the spontaneous emission and its potential applications in high-precision spectroscopy.

We investigate the features of the spontaneous emission spectra in a cold five-level atomic system coupled by a single elliptically polarized control field. We use wave function approach to derive the explicit and analytical expressions of atomic spontaneous emission spectra. It is shown that some interesting phenomena such as spectral-line enhancement, spectral-line suppression, spectral-line narrowing, spectral-line splitting and dark fluorescence can be observed in the spectra by appropriately modulating the phase difference between the right-hand circularly (LHC) and left-hand circularly (RHC) polarized components of the elliptically polarized control field and the intensity of external magnetic field. The number of emission peaks, the positions of fluorescence-quenching points can be also controlled. Furthermore, we propose an ultracold 87Rb atomic system for experimental observation. These investigations may find applications in high-precision spectroscopy.

We propose a new scheme for realizing deterministic quantum state transfer (QST) between two spatially separated single molecule magnets (SMMs) with the framework of cavity quantum electrodynamics (QED). In the present scheme, two SMMs are trapped in two spatially separated optical cavities coupled by an optical fiber. Through strictly numerically simulating, we demonstrate that our scheme is robust with respect to the SMMs' spontaneous decay and fiber loss under the conditions of dispersive SMMs-field interaction and strong coupling of cavity fiber. In addition, we also discuss the influence of photon leakage out of cavities and show that our proposal is good enough to demonstrate the generation of QST with high fidelity utilizing the current experimental technology. The present investigation provides research opportunities for realizing QST between solid-state qubits and may result in a substantial impact on the progress of solid-state-based quantum communications network.

The temporal and spatial dynamics of one weak probe laser pulse, propagating through a A-type atomic medium with two-folded levels under the resonant excitation of one microwave driving field and one strong control field, is investigated in this paper. By numerically solving coupled Bloch-Maxwell equations, it is found that, in the absence of the microwave driving field, the atomic medium is transparent to the probe pulse at line center, which propagates over sufficiently long distances. By contrast, when the microwave driving field is applied, the probe pulse at line center can be rapidly absorbed on propagation. This substantial reduction of probe transmittance caused by the microwave driving field may lead to potential applications in designing a new kind of optical switching.

This paper investigates the generation and evolution of continuous-variable entanglement in an asymmetric coupled-quantum well (CQW) system. Our numerical results show that this CQW system can be regarded as a source of macroscopic entangled light over a wide range of initial states of the cavity field. This investigation can be used for achieving the macroscopic entangled light in the CQW solid-state medium, which is much more practical than that in an atomic medium because of its flexible design and the controllable interference strength.

We investigate the formation of optical bistability (OB) in a crystal of molecular magnets contained in a unidirectional ring cavity. The crystal is subjected to one dc magnetic field and two (probe and coupling) ac resonant magnetic field. The results show that OB can be controlled efficiently by adjusting the intensity of the control field, the detuning of probe magnetic field and the cooperation parameter. Furthermore, within certain parameter range, the optical multistablity (OM) can also be observed in the crystal medium. This investigation can be used for designing new types of nonelectronic devices for realizing switching process.

We present a weak-coupling theory of semiclassical periodically driven two-level systems. The explicit analytical approximating solution is shown to reproduce highly accurately the exact results well beyond the regime of the rotating-wave approximation.

We study the dynamics of a two-level trapped ion in a standing wave electromagnetic field in two-dimensional (2D) noncommutative spaces in the Lamb–Dicke regime under the rotating wave approximation. We obtain the explicit analytical expressions for the energy spectra, energy eigenstates, unitary time evolution operator, atomic inversion, and phonon number operators. The Rabi oscillations, the collapse, and revivals in the average atomic inversion and the average phonon number are explicitly shown to contain the information of the parameter of the space noncommutativity, which sheds light on proposing new schemes based on the dynamics of trapped ion to test the noncommutativity.

We present a systematic study on the formation of ultra-slow bright and dark optical solitons in highly resonant media. By investigating four life-time broadened atomic systems, i.e., three-state Λ-type and cascade-type schemes, and four-state N-type and cascade-type schemes, we show that the formation of such ultra-slow solitons in cold atomic systems is a fairly universal phenomenon.

We study the four-wave mixing (FWM) in a double-Λ atomic system where two strong continuous-wave pump lasers and a weak pulsed probe laser produce an FWM generated pulse. We show that both the probe and FWM generated fields may evolve into bright and dark solitons with the same shape and the same ultraslow group velocity.

We present the explicit analytical expressions of the steady-state probability amplitudes and populations of atom levels in N-photon electromagnetically induced transparency for an arbitrary positive integer N.

Taking a coherent state representation, we derive the nonlinear Schrodinger-type differential-difference equations from the quantized model of an array of traps containing Bose–Einstein condensates and linked by the tunnelling process among the adjacent traps. It is shown that no matter whether two-body interactions among atoms are repulsive or attractive, a nearly uniform atom distribution can evolve into a bright soliton-type localized ensemble of atoms and a lump of atom distribution can also be smeared out by redistributing atoms among traps under appropriate initial phase differences of atoms in adjacent traps. These two important features originate from the tailoring effect of the initial phase conditions in coherent tunnelling processes, which differs crucially from the previous tailoring effect coming mainly from the periodicity of optical lattices.

We derive exact analytical expressions of time-evolving bare-state operators of level occupation numbers and the photon numbers for a composite system consisting of a three-level atom interacting with two modes of a quantized electromagnetic held in A configuration. These results demonstrate the oscillations with three-family frequencies for a nonzero detuning, which dramatically differ from the previous results showing only single-family Rabi oscillations.

In this paper, we derive the exact analytical expressions of the transition probabilities among the Fock states of an ion in a harmonic trap due to the presence of an alternating electric field.

We show that the evolution equations for mean quantities such as atom numbers and the inter-mode correlation for two-mode Bose-Einstein condensates form a closed set of equations in the SU(2) coherent state description, and they are identical in form to the two-mode mean-field model with only a slightly reduced two-body interaction strength. The exact analytical solutions to the evolution equations are also presented.

We present the analytical solutions to the two-mode mean-field model for a split Bose-Einstein condensate. These explicit solutions completely determine the system's dynamics under the two-mode mean-field approximation for all possible initial conditions.

We develop a simple approach to obtain explicitly exact analytical expressions of particle and kinetic-energy densities for noninteracting Fermi gases in one-dimensional harmonic confinement, and in one-dimensional box confinement as well.

The model of double-well Bose–Einstein condensates in the strong-interaction regime is shown to reduce adiabatically to an effective two-state model describing the Rabi oscillations between the two atomic Fock states |N, 0〉 and |0, N〉, and the NOON states of arbitrary ultracold atoms can therefore be generated periodically from the initial state of either one of the Fock states.

The carrier-envelope phase (CEP) of few-cycle laser pulses is shown to have profound effects on the bound-state atomic coherence even in the weak-field regime where ionizations hardly take place, and a simple scheme is proposed to measure such CEP-dependent atomic coherence.

We derive an explicit analytical expression of the efficiency for a scheme of four-wave mixing (FWM) in a ladder-type lifetime broadened four-level atomic system and show that this scheme can achieve an FWM efficiency higher than the previous ultraslow light FWM schemes.

We derive the analytical expression of microcavity-enhanced factor for third harmonic generation in terms of detunings, linewidths, and the Purcell factors of the relevant microcavity modes. It is suitable for microcavities with any dimensions and arbitrary geometric shapes.

We investigate continuous-wave four-wave mixing via electromagnetically induced transparency in double-A configuration by using Schrodinger-Maxwell formalism. We derive the corresponding explicit analytical expressions.

We show that there exist a series of coherent superposition states of atoms and molecules in a dilute Bose-Einstein condensate with exactly balanced photo-associations and photo-dissociations, and their analytical expressions are explicitly given. They also correspond to the coherent superposition states of two kinds of photons in optical second harmonic generation processes, which shows exactly balanced down- and up-conversions.

We present a novel formalism for energy eigenvalue problems when the corresponding Hamiltonians can be expressed as a function of an angular momentum. The problems are turned into finding operator polynomials by solving a c-number differential equation. Simple and efficient computer-aided analytical and numerical methods may be developed based on the formalism.

We find a class of new nonlinear Bogoliubov transformations and solve the eigenvalue problem of the model Hamiltonian describing the second harmonic generation with intensity-dependent coupling. These transformations differ from the previously known nonlinear quadrature-dependent Bogoliubov transformations.

We derive the phonon spectrum and the corresponding modulational instability conditions of an array of traps containing Bose-Einstein condensates with each trap linked to adjacent traps by tunnelling. It is shown that modulational instability regimes always exist regardless of the sign of the two-body interaction.

It is shown that the semiclassical description of the coherent two-colour photoassociation of a Bose-Einstein condensate can be put into the canonical Hamiltonian formalism. This considerably simplifies the investigation of the corresponding steady states and their quantum fluctuations, and corresponding dynamics.

We propose a new method for the energy eigenvalue problem for boson systems with either weak or strong two-body interactions. It is also shown that this method is particularly simple and effective for obtaining the explicit analytical expressions of energy eigenvalues and eigenstates for interacting harmonic oscillators especially when the number of oscillators is huge.

The two-dimensional higher order Korteweg de Vries equations of Lax hierarchy are constructed. Their soliton chain solutions are derived by Hirota's bilinear transformation method, and the various variants of the soliton chain solutions are investigated in some details.