Nonlinear resonances in the absorption spectrum of the three-level atomic V system in strong polyharmonic and weak biharmonic fields

A three-level atomic system with a strong three-mode field and a probing biharmonic field at transitions 1→2 and 1?3 (1 is a common lower level), respectively, is studied theoretically by numerical simulation and an analysis of the mathematical expressions derived for the particular case of a symmetric arrangement of the strong field components relative to the transition frequency ω₂₁. The absorption spectrum of the probing field components contains parametric supernarrow resonances against the background of resonances of the nonlinear interference effect. The ratios of the differences in the frequencies of the strong and probing fields, at which the supernarrow resonances appear, are found analytically. The results coincide with those obtained from numerical simulation.     

Berry phases in the three-level atoms driven by quantized light fields

A theoretical analysis of Berry’s phases is given for the three-level atoms interacting with external one-mode and two-mode quantized light fields. Three main results are obtained: (i) There is a Berry phase which vanishes in the classical limit or this Berry phase is completely induced by the field quantization; (ii) Berry’s phases for the one-mode field and the two-mode field can be equal so long as the photon numbers of the two-mode field are properly chosen; (iii) In the two-mode case, Berry phases of the atom interacting with one mode is affected by the other mode even if the photon number of the other mode is zero.      

Polarization and trapping of weakly bound atoms in penning trap fields

The ATHENA and ATRAP groups at CERN recently reported the production of weakly bound antihydrogen atoms in a non-neutral positron-antiproton plasma. This Letter derives an equation of motion for weakly bound atoms in the electric and magnetic fields of the plasma and trap. The atoms are polarized by the electric field and can be trapped radially in the edge region of the plasma where the electric field is maximum.     

The entropy of entangled three-level atoms interacting with entangled cavity fields: Entanglement swapping

The dynamics of an entangled atomic system, partially interacting with entangled cavity fields and characterizing an entanglement swapping, has been studied through their von Neumann entropies. The aforementioned interaction is implemented via a two-photon process, given by either the full microscopical Hamiltonian approach or the two-photon Jaynes-Cummings model. Numerical simulations furnish the explicit expressions for each sub-system entropy, which allow us to estimate the multiperiodicity in the evolution of the entangled atom-field system. The effects of the detuning parameter upon the period and the amplitude of the entropies are also discussed as well as the power spectrum of the entropy.     

Shape invariant propagation of polychromatic fields

When a polychromatic field propagates the transverse distribution of the power spectrum generally changes from one plane to another. Conditions are found under which the spectrum distribution maintains the same shape in any cross-section. Examples of fields satisfying these conditions are given.     

Resonance fluorescence spectrum of a three-level atom driven by coherent and stochastic fields

The dressed-state populations and the resonance fluorescence spectrum of a V-type three-level atom driven by a strong coherent field and a weak stochastic one simultaneously are investigated. There can be significant population inversion due to the effect of the stochastic field. The atomic resonance fluorescence spectrum can be controlled by adjusting the frequency difference between the coherent field and the stochastic one and the coherent Rabi frequency. Peak suppression and line narrowing occur under appropriate conditions. Received 23 June 2000 and Received in final form 18 January 2001     

Three-dimensional localization of atoms in the polychromatic optical superlattice

Quasiclassical kinetic theory of the light pressure force has been applied to describe the localization of atoms (or ions) with the transition F=1→F=0 in the three-dimensional (3D) dissipative optical superlattice of a new type. Its action is based on the effect of the gradient force rectification in the polychromatic field: superposition of the three color far-off-resonant field and partially coherent resonant field. An approximate explicit solution of the kinetic equation for 3D motion of atoms in such a (multicolor) field has been achieved. This solution demonstrates the capability of the polychromatic superlattice to provide efficient cooling and strong spatial localization of the particles and to form an atomic (or ionic) grating with highly controllable characteristics.     

Evolution of an optically pumped ensemble of cold ground-state atoms in weak light fields

The evolution of multipole moments is analyzed for optically pumped cold ground-state atoms in the limit of low saturation of a closed j₀ → j₁ dipole transition. The longest multipole-moment relaxation times are analyzed as functions of ellipticity and frequency detuning from resonance for transitions with j₀ ? 5. The qualitative difference between the evolution toward steady-state Zeeman sublevel populations and dynamics of transient spontaneous emission is demonstrated for transitions of the following types: j → j?1, j → j with integer j, j → j with half-integer j, and j → j + 1.     

Ionization of atoms in weak fields and the asymptotic behavior of higher-order perturbation theory

Using the imaginary time method, we study the structure of the perturbation series for the hydrogen atom in electric ℰ and magnetic ℋ fields. It is shown that there is a “critical” value of the ratio γ=ℋ|ℰ at which the perturbation series for the ground state changes from having a fixed sign (for γ<γ _c ) to having a variable sign (for γ>γ _c ). This conclusion is confirmed by direct higher-order perturbation calculations. The change in the asymptotic regime is explained by competition among the contributions of the various complex trajectories that describe the subbarrier motion of the electrons. Here the parameter γ _c depends on the angle θ between the electric and magnetic fields. Zh. éksp. Teor. Fiz. 113, 2047–2055 (June 1998)     

Quantum beats from dressed three-level atoms

By extending a previously developed unitary transformation technique to dress three-level atoms by a strong driving radiation field, we show that quantum beats can be induced by the presence of the driving field also when the decay channels lead from a singlet to a doublet of lower energy. A qualitative explanation of this effect is presented, which is based on the quantum theory of measurement.     

双模腔场中-型三能级原子的辐射谱

采用时间演化算符方法,研究-型三能级原子与双模腔场共振相互作用的辐射谱,尤其在真空场中拉比（Rabi）分裂.给出了辐射谱一般公式。并讨论在粒子数纯态光场激励下的辐射频谱结构。结果表明：一般辐射谱呈对称的12蜂结构.     

Continued-fraction theory of transitions within three-level atoms

Different continued-fraction formalisms of the eigenvalue problem involving three atomic levels are shown to yield expressions for resonance lineshapes equivalent to those obtained using degenerate perturbation theory. New expressions for the linewidth and distortion of a spin-1 resonance are given.     

Rydberg atoms in magnetic fields — The landau limit of the atomic spectrum

We present some of the more striking experimental aspects of the quasi-Landau atomic spectrum in a magnetic field, observed near and above the zero field ionization threshold. The Landau limit is shown to be almost reached in our experiments on caesium, led at fixed electron energies scanning the magnetic field.     

Theory of degenerate four-wave mixing in three-level atoms

We derive a theoretical model for phase conjugation in three level atoms. The atoms are assumed to be at rest and the intensities I₁ and I₂ of the pump beams can take arbitrary large values. We calculate the lineshape for a thin optical medium in the case of plane waves and of gaussian beams. In the case of a thick optical medium, we show that the gain saturates if I₁ ≠ I₂.     

Fluctuations in a single-mode laser using three-level atoms

The quantum model of a single-mode laser is extended completely to the case of three-level atoms. A closed equation for the field density matrix is obtained by the perturbation-theory method developed in earlier work of the authors. Quadratic dispersion of the quasiprobability function is found, and the physical meaning of the terms therein is discussed. In the general case, the impossibility of reducing information about nonworking levels to two relaxation constants of a two-level system is shown.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 92–94, February, 1984.The authors are grateful to D. N. Zubarev for attention to the research, and also to S. D. Tvorogov, E. P. Gordov, and G. I. Surdutovich for useful discussions.     

Soliton-induced transparency of inhomogeneously broadened three-level atoms

The effect of soliton-induced transparency (SOIT) that arises for a weak pulse that interacts with one of allowed transitions of inhomogeneously broadened three-level atoms with the V configuration of the levels under the action of a self-induced transparency soliton that simultaneously interacts with the adjacent transition is studied theoretically. The effect is explained by phasing of the ensemble of dipoles oscillating with different frequencies in the soliton field. The weak pulse is locked by the soliton, so that both pulses propagate with the same velocity independently of the ratio of the propagation constants. If the latter are equal, the weak pulse loses no energy; when they are different, the rate of energy loss is considerably slower than it follows from Beer’s law.     

Two-mode mazer injected with V-type three-level atoms

The properties of the two-mode mazer operating on V-type three-level atoms are studied. The effect of the oneatom pumping on the two modes of the cavity field in number-state is asymmetric, that is, the atom emits a photon into one mode with some probability and absorbs a photon from the other mode with some other probability. This effect makes the steady-state photon distribution and the steady-state photon statistics asymmetric for the two modes. The diagram of the probability currents for the photon distribution, given by the analysis of the master equation, reveals that there is no detailed balance solution for the master equation. The computations show that the photon statistics of one mode or both modes can be sub-Poissonian, that the two modes can have anticorrelation or correlation, that the photon statistics increases with the increase of thermal photons, and that the resonant position and strength of the photon statistics are influenced by the ratio of the two coupling strengths of the two modes. These properties are also discussed physically.     

Berry phase effects in two-level and three-level atoms

Group-theoretical methods are developed for treating Berry phase effects, which are related to Cartan subalgebra. The theory is applied to two-level and three-level atoms interacting with perturbations that are described by the SU(2) or SU(3) algebra. By using fiber-bundle theories, it is found that a time development operator that depends on Cartan group generators can represent a fiber while a time development operator that depends on other generators of the group represents the base of the quantum manifold. The total time development operator is obtained by multiplication of these two parts and the fiber-bundle theory is applied for calculating Berry phase effects. Explicit expressions for Berry phases are obtained under the adiabatic approximation.     

Special features of the dynamics of multipole moments of atoms at rest in weak light fields

The dynamics of radiative relaxation of multipole moments of atoms at rest in the ground state is considered for a low degree of dipole transition saturation. Using the field representation in the bipolar harmonic basis, the special features of the characteristic relaxation times are studied as functions of the j_g j_e transition type, ellipticity, and field frequency offset from resonance.__________Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 57–64, December, 2004.