Rate efect and coupled evolution of atomic motions and potential landscapes

Since rate effect of materials plays a key role in impact engineering, the microscopic mechanism of rate effect is investigated at molecular level in this paper. The results show that rate effect on the strength of atomic system is closely related to the coupled evolution of atomic motions and potential landscapes. Accordingly, it becomes possible to develop a new algorithm of molecular simulation, which could properly and efficiently demonstrate strain rate effect under a wide range of loading rates and unveil the mecha- nisms underlying the strain rate effects.

＂Pseudo-invariant Eigen-operator＂ Method for Deriving Energy-Gap of an Atom-Cavity Jaynes-Cummings Hamiltonian with Atomic Centre-of-Mass Motion

Using the ＂pseudo-invariant eigen-operator＂ method we find the energy-gap of the Jaynes-Cummings Hamiltonian model of an atom-cavity system. This model takes the atomic centre-of-mass motion into account. The supersymmetric structure is involved in the Hamiltonian of an atom-cavity system. By selecting suitable supersymmettic generators and using supersymmetrie transformation the Hamiltonian is diagonalized and energy eigenvectors are obtained.

Quantum entanglement between the two-mode fields and atomic entropy squeezing in the system of a moving atom interacting with two-mode entangled coherent field

This paper investigates the entropy squeezing of a moving two-level atom interacting with the two-mode entangled coherent field via two-photon transition by using an entropic uncertainty relation and the degree of entanglement between the two-mode fields by using quantum relative entropy.The results obtained from numerical calculation indicate that the squeezed period,the duration of entropy squeezing and the maximal squeezing can be controlled by appropriately choosing the intensity of the light field,the atomic motion and the field-mode structure.The atomic motion leads to the periodic recovery of the initial maximal degree of entanglement between the two-mode fields.Moreover,there exists a corresponding relation between the time evolution properties of the atomic entropy squeezing and those of the entanglement between the two-mode fields.

Preparation and control of entangled states in the two-mode coherent fields interacting with a moving atom via two-photon process

We investigate the preparation and the control of entangled states in a system with the two-mode coherent fields interacting with a moving two-level atom via the two-photon transition. We discuss entanglement properties between the two-mode coherent fields and a moving two-level atom by using the quantum reduced entropy, and those between the two-mode coherent fields by using the quantum relative entropy. In addition, we examine the influences of the atomic motion and field-mode structure parameter p on the quantum entanglement of the system. Our results show that the period and the duration of the prepared maximal atom-field entangled states and the frequency of maximal two-mode field entangled states can be controlled, and that a sustained entangled state of the two-mode field, which is independent of atomic motion and the evolution time, can be obtained, by choosing appropriately the parameters of atomic motion, field-mode structure, initial state and interaction time of the system.

Entropy squeezing of a moving atom and control of noise of the quantum mechanical channel via the two-photon process

Based on the quantum information theory, we have investigated the entropy squeezing of a moving two-level atom interacting with the coherent field via the quantum mechanical channel of the two-photon process. The results are compared with those of atomic squeezing based on the Heisenberg uncertainty relation. The influences of the atomic motion and field-mode structure parameter on the atomic entropy squeezing and on the control of noise of the quantum mechanical channel via the two-photon process are examined. Our results show that the squeezed period, duration of optimal entropy squeezing of a two-level atom and the noise of the quantum mechanical channel can be controlled by appropriately choosing the atomic motion and the field-mode structure parameter, respectively. The quantum mechanical channel of two-photon process is an ideal channel for quantum information （atomic quantum state） transmission. Quantum information entropy is a remarkably accurate measure of the atomic squeezing.

THE EFFECT OF ENVIRONMENT WORK ON EFFECTIVE SEGREGATION COEFFICIENT OF SOLUTE AT SOLID／LIQUID INTERFACE

The model of effective segregation coefficient(Keff) of solute atoms has been developed by considering the effect of environment work on barrier potential of atom motion at solid/liquid interface.It was found that not only the amount but also the type of environ ment work strongly affected the Keff in addition to the growth velocity R.

Emission spectrum of a harmonically trapped Λ-type three-level atom

We theoretically investigate the emission spectrum for a A-type three-level atom trapped in the node of a standing wave. We show that the atomic center-of-mass motion not only directly affects the peak number, peak position, and peak height in the atomic emission spectrum, but also influences the effects of the cavity field and the atomic initial state on atomic emission spectrum.

Nonreciprocal transmission of multi-band optical signals in thermal atomic systems

Multi-band signal propagation and processing play an important role in quantum communications and quantum computing.In recent years,optical nonreciprocal devices such as an optical isolator and circulator are proposed via various configurations of atoms,metamaterials,nonlinear waveguides,etc.In this work,we investigate all-optical controlled nonreciprocity of multi-band optical signals in thermal atomic systems.Via introducing multiple strong coupling fields,nonreciprocal propagation of the probe field can happen at some separated frequency bands,which results from combination of the electromagnetically induced transparency(EIT) effect and atomic thermal motion.In the proposed configuration,the frequency shift resulting from atomic thermal motion takes converse effect on the probe field in the two opposite directions.In this way,the probe field can propagate almost transparently within some frequency bands of EIT windows in the opposite direction of the coupling fields.However,it is well blocked within the considered frequency region in the same direction of the coupling fields because of destruction of the EIT.Such selectable optical nonreciprocity and isolation for discrete signals may be greatly useful in controlling signal transmission and realizing selective optical isolation functions.