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1.
A. V. Andreev 《JETP Letters》2000,72(5):238-240
A system of equations is suggested for the interaction of an atom with an electromagnetic field of arbitrary intensity. The distinctive feature of the equations is that, in the absence of the field, the electron density in the atom is determined by the Schrödinger equation and, in the presence of the field, by the equation resembling the classical equation for an electron in the Lorentz force field.  相似文献   

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We compute the scattering operator for a simplified model of an atom interacting a with a quantized field. The field is restricted to the vacuum and one-particle sectors, and the atom has only two states. We also solve the inverse scattering problem for the same model. The methods used rely on the particular form of the interaction, which is chosen to mimic the interaction between radiation and matter.This work was partially supported by NSF Grant DMS-8922941.  相似文献   

4.
The electronic transitions and emission of an atom during its interaction with a spatially inhomogeneous ultrashort pulse of electromagnetic field are considered. The probabilities of excitation and ionization, as well as the spectra and cross sections of reemission of such a pulse by the atom, are obtained. As an example, the one-and two-electron inelastic processes accompanying the interaction of ultrashort pulses with hydrogen-and helium-like atoms are considered.  相似文献   

5.
An analytical expression for a matrix element of the transition from a bound state of an electron in an atom to continuum states is obtained by solving the problem of interaction of the electron with a quantized electromagnetic field. This expression is used to derive formulas for the photoelectron spectrum and the rate of ionization of the simplest model atomic system upon absorption of an arbitrary number of photons. The expressions derived are analyzed and compared with the corresponding relationships obtained via other approaches. It is demonstrated that there are differences as compared to the case of the classical field. In particular, the photoelectron spectrum exhibits dips due to the destructive interference of the transition amplitudes in the quantized electromagnetic field.  相似文献   

6.
A theoretical scheme for the generation of maximally entangled states of two superconducting flux qubits via their sequential interaction with a monochromatic quantum field is presented. The coupling of the qubits with the quantized field can be tuned on and off resonance by modulating the effective Josephson energy of each qubit via an externally applied magnetic flux. The system operates in such a way as to transfer the entanglement from a bipartite field-qubit subsystem to the two qubits. This scheme is attractive in view of the implementation of practical quantum processing systems.  相似文献   

7.
The time evolution of the process of excitation of an atom in the field of a laser wave is considered. It is shown that there exist three stages of relaxation. The first stage carries the most complete information about the mechanism of the interaction of the field with material inside the laser source.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 23–27, June, 1981.  相似文献   

8.
A new representation of the interaction between a laser field and an atom is obtained. The Fourier component of the interaction is represented as a multipole expansion dependent on the force parameter of the field, a 0=F2, and the degree of its ellipticity, η. This representation provides the analytical separation of the angles in the time-dependent Schrödinger equation. The stationary spherically symmetric part of the potential V 0(r, a 0, η) of a “field-dressed” atom is singled out. The application of the new representation to the calculation of nonlinear effects and electron scattering by an atom in a field are discussed  相似文献   

9.
运动的二能级原子与双模量子化腔场的相互作用   总被引:5,自引:0,他引:5       下载免费PDF全文
陈爱喜  吴曙东  金丽霞  詹志明 《物理学报》2003,52(10):2466-2470
研究了一个微波激射器, 其腔内是单个运动的二能级原子与一双模量子化腔场的相互作用. 用修饰态来描述系统态矢量, 分析了在热原子状态下, 双模光场配制成不同的状态, 失谐量 对微波激射器的原子辐射率的影响. 关键词: 二能级原子 双模量子化腔场 原子辐射率  相似文献   

10.
We develop the theory of interaction of the electromagnetic field and a single atom being in an arbitrary state and having an arbitrary direction of the angular momentum of the atomic electron with respect to the direction of the field polarization vector. It is shown that the atom response current has a tensor structure and depends on both the direction of the angular momentum of the atom, and the polarization vector of the external field. The tensor character of the response is determined by the externally induced anisotropic distribution of the probability density of spatial localization of the atomic electron. It is shown that the induced-anisotropy effects clarify the harmonic generation mechanism at play during the non-resonance interaction of laser radiation with atomic media. The developed theory is applied to the analysis of the problem about the generation of terahertz waves in a two-color laser field. It is shown that the change in the mutual orientation of wave polarization vectors leads to a significant increase in the efficiency of conversion of high-frequency fields to low-frequency ones. It is shown for the first time that the generation of terahertz waves is possible in the preionization regime, when the generation mechanism is related to atomic nonlinearity.  相似文献   

11.
The violation of charge symmetry in the known [1] wave functions for an electron in a quantized wave field is considered. An attempt is made to modify the equations and to construct solutions free of this deficiency.  相似文献   

12.
Electron transitions occurring during the interaction of a heavy relativistic atom with a spatially inhomogeneous ultrashort electromagnetic pulse are considered by solving the Dirac equation. The corresponding transition probabilities are expressed in terms of known inelastic atomic form factors, which are widely used in the theory of relativistic collisions between charged particles and atoms. By way of example, the inelastic processes accompanying the interaction of ultrashort pulses with hydrogen-like atoms are considered. The probabilities of ionization and production of a bound-free electron-positron pair on a bare nucleus, which are accompanied by the formation of a hydrogen-like atom in the final state and a positron in the continuum, are calculated. The developed technique makes it possible to take into account exactly not only the spatial inhomogeneity of an ultrashort electromagnetic pulse, but also the magnetic interaction.  相似文献   

13.
The resonant interaction of a single atom with a single quantized field mode characterized by sub-Poissonian statistics is compared with its interaction with a coherent field mode. Two models are considered: the Jaynes-Cummings model (JCM) and the Raman-coupled model (RCM). Quadrature squeezing variances and photon number uncertainties are evaluated. In the JCM, sub-Poissonian field statistics lead to longer collapse times and more complete revivals than Poissonian statistics. In the RCM, which is characterized by periodic collapses and revivals, the collapse time is longer for sub-Poissonian fields.This work was supported in part by the UK Science and Engineering Research Council.  相似文献   

14.
The expression for the force exerted by the field on an atom and averaged over the field period is derived in quantum-mechanical perturbation theory, in which a quasi-monochromatic electromagnetic field plays the role of a perturbation. An approximate solution is obtained to the classical (Newton) equation of motion in the same field for a harmonic isotropic oscillator. In both problems, the expressions for the force acting on a particle are completely identical if they are written in terms of the polarizability (of the atom and the oscillator). These results conform with the data obtained in macroscopic electrodynamics for rarefied media.  相似文献   

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Because induced emission is an incoherent phenomenon, it is impossible to represent the Gibbs thermodynamic potential of a quantized electromagnetic field in an absorbing medium in terms of the standard refractive index with an imaginary component. This is completely true with respect to the entropy of the electromagnetic field, the heat capacity, and the state equation, as well as to the stationary ponderomotive forces. The so-called causal refractive index arises in the theory, which differs from the standard refractive index in the analytical properties. The ideality condition of the photon gas in dissipative media does not hold without using the causal refractive index. The Kirchhoff law holds true only if the causal refractive index negligibly differs from unity.  相似文献   

17.
The dynamics of a model atomic system interacting with a quantum electromagnetic field has been investigated. The effect of statistics and average number of photons in a quantum state of the field on the ionization and stabilization of the atomic subsystem has been studied. The formation of a state with the maximum entanglement between the atomic and field subsystems in the case of interaction with a single-photon field has been demonstrated.  相似文献   

18.
How the mean photon number, the probability of excited state and intrinsic decoherence coefficient influence the time evolution of entanglement is unknown, when a single-mode quantized optic field and a two-level atom coupling system is governed by Milburn equation. The Jaynes-Cummings model is considered. A lower bound of concurrence is proposed to calculate the entanglement. Simulation results indicate that the entanglement of system increases following the increasing of intrinsic decoherence coefficient or the decreasing of the mean photon number. Besides that, the entanglement of system decreases, while the probability of exited state increases from 0 to 0.1, and increases, while the probability of exited state increases from 0.1 to 1.  相似文献   

19.
How the mean photon number, the probability of excited state and intrinsic decoherenee coefficient in-fluence the time evolution of entanglement is unknown, when a single-mode quantized optic field and a two-levelatom coupling system is governed by Milburn equation. The Jaynes-Cummings model is considered. A lowerhound of concurrence is proposed to calculate the entanglement. Simulation results indicate that the entanglementof system increases following the increasing of intrinsic decoherence coefficient or the decreasing of the mean photon number. Besides that, the entanglement of system decreases, while the probability of exited state increasesfrom 0 to 0.1, and increases, while the probability of exited state increases from 0.1 to 1.  相似文献   

20.
单模光场与二能级原子的纠缠的内禀退相干   总被引:1,自引:0,他引:1  
在一个考虑了内禀退相干的单模光场与二能级原子的耦合系统中,平均光子数,激发态的概率和退相干系数如何影响纠缠随时间演化还并不清楚.Jaynes-Cummings模型被用来描述光场与原子间相互作用.用concurrence下限来计算纠缠度.模拟的结果表明纠缠度随着退相干系数的增加或平均光子数的减少而增加.当激发态的概率在0至0.1之间,纠缠度随着的概率增加而减少;当激发态的概率在0.1至1之间,纠缠度随着的概率增加而增加.无论以上参数取何值,纠缠度都随着时间而减少.  相似文献   

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