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  • 1
    Electronic Resource
    Electronic Resource
    Quantum theory of resonant scattering of atoms by a pulsed field under coherent population trapping conditions (1998)
    Springer
    Journal of experimental and theoretical physics 86 (1998), S. 49-60 
    Details
    ISSN: 1090-6509
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We develop an entirely quantum mechanical analytical description of scattering of atoms with angular momenta j g →j→j e =j (j is an integer) by a pulsed σ +−σ − field. In the stationary-atom approximation with exact accounting for recoil effects, we solve the problem of the change in the distribution of atoms among the internal and translational degrees of freedom initiated by a single pulse for j g =1, 2. We find in analytical form recurrence formulas that make it possible to calculate the distribution of the atoms after an arbitrary sequence of pulses has acted on the system. We show that for discrete (resonant) values of the time interval between the pulses, the action of N pulses leads to effective formation and narrowing of peaks at discrete points in momentum space and to a broadening of the envelope of these peaks. In the case of a broad initial momentum distribution we derive explicit formulas for the peaks and the envelope and study their asymptotic behavior for N≫1. Finally, in the weak-field limit we study numerically the dependence of the contrast of the scattering diagram on pulse length.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.558468
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  • 2
    Electronic Resource
    Electronic Resource
    Kinetics of atoms in an elliptically polarized standing wave (1999)
    Springer
    Journal of experimental and theoretical physics 88 (1999), S. 433-440 
    Details
    ISSN: 1090-6509
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We examine the kinetics of atoms with their ground and excited states being degenerate in the projection of angular momentum. The atoms are located in a standing wave with uniform elliptical polarization. Using the j g =1/2→j e =1/2 transition as an example, we show that the friction and diffusion of atoms strongly depend on the ellipticity of the field. For instance, in the low saturation limit the frictional force contains, in addition to the ordinary Doppler friction term, a term that can be interpreted as Sisyphean friction. Under certain conditions, the contributions reflecting the degeneracy of the ground state are dominant, with the result that the values of the friction and diffusion coefficients (and hence the rate of kinetic processes) may differ from the values predicted by the two-level atomic model by several orders of magnitude.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.558813
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  • 3
    Electronic Resource
    Electronic Resource
    Atom in an elliptically polarized resonance field: Exact stationary solution (1996)
    Springer
    JETP letters 64 (1996), S. 7-12 
    Details
    ISSN: 1090-6487
    Keywords: 32.80.−t
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract An analytical method is developed for finding the exact stationary solution for the density matrix of atoms in a monochromatic resonance field of arbitrary ellipticity and intensity. A solution for the transitions F g=F → F e=F+1 (F g and F e are the angular momenta of the ground and excited states) is obtained in an analytical invariant form. The properties of this solution are investigated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.567162
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  • 4
    Electronic Resource
    Electronic Resource
    On the spontaneous-coherence-transfer-induced sign change of a sub-natural-width nonlinear resonance (1999)
    Springer
    JETP letters 69 (1999), S. 819-824 
    Details
    ISSN: 1090-6487
    Keywords: 42.65.−k ; 42.50.Gy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A simple theoretical model is proposed which describes the positive sign of the nonlinear absorption resonances in the experiments of Akul’shin et al. [Phys. Rev. A 57, 2996 (1998)]. An analytical expression for the linear response to a weak probe field is obtained in the weak-saturation limit. It is shown that the positive sign of sub-natural-width resonances is due to the spontaneous transfer of low-frequency coherence from an excited level to the ground state.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.568096
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  • 5
    Electronic Resource
    Electronic Resource
    Influence of atomic motion on the shape of two-photon resonance in gas (2000)
    Springer
    JETP letters 72 (2000), S. 119-122 
    Details
    ISSN: 1090-6487
    Keywords: 42.50.Gy ; 42.62.Fi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A gas of three-level atoms with Λ configuration of energy levels was taken as an example to demonstrate that the influence of particle motion on the two-photon resonances extends further than the residual Doppler shift (k 1−k 2)v. In particular, a narrow dip in the absorption spectrum (“dark” resonance) undergoes substantial narrowing, as compared to the atoms at rest. The width of this resonance is studied nonperturbatively as a function of the intensities of probe and strong fields.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.1316812
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  • 6
    Electronic Resource
    Electronic Resource
    Tensor structure of the stationary point of the radiative relaxation operator of an atom (1998)
    Springer
    Journal of experimental and theoretical physics 87 (1998), S. 70-75 
    Details
    ISSN: 1090-6509
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We formulate the problem of the stationary point of the operator of radiative relaxation of an atom: the initial distribution among the sublevels of the excited state, whose nonzero eigenvalues (populations) coincide with the populations of the final distribution (after spontaneous decay) among the sublevels of the ground state. We show that these distributions can be expressed in terms of spherical functions of the complex direction. The results are then used to develop a compact analytical representation of the stationary density matrix of atoms interacting with an elliptically polarized monochromatic field.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.558627
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  • 7
    Electronic Resource
    Electronic Resource
    Quantum theory of cooling of atoms below the one-photon recoil energy by a pulsed field (1997)
    Springer
    JETP letters 65 (1997), S. 779-784 
    Details
    ISSN: 1090-6487
    Keywords: 32.80.Pj
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A completely quantum-analytical description of the cooling of atoms with angular momenta j g =1→j e =1 by a pulsed σ 1−σ − field is developed. The problem of the change produced in the distribution of the atoms over the internal and translational degrees of freedom by a single field pulse is solved exactly with respect to recoil effects. Recurrence formulas for the distribution after the action of an arbitrary sequence of pulses are found in analytical form. It is shown that N field pulses result in the formation and narrowing of peaks at discrete points in momentum space as well as broadening of the envelope of these peaks. Explicit formulas are obtained for the peaks and envelopes in the case of a wide initial momentum distribution, and their asymptotic behavior for N≫1 is investigated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.567426
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  • 8
    Electronic Resource
    Electronic Resource
    New friction force due to spontaneous light pressure (1999)
    Springer
    JETP letters 70 (1999), S. 443-449 
    Details
    ISSN: 1090-6487
    Keywords: 32.80.−t ; 42.50.Vk
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We have discovered a new friction force, acting on an atom in the field of two oppositely propagating elliptically polarized waves of low intensity. In contrast to the well-known friction forces, the new force does not vanish at zero detuning of the field from resonance, and the direction of the kinetic process (heating or cooling) is determined by the relative orientation and the ellipticity of the polarization vectors of the oppositely propagating waves.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.568194
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  • 9
    Electronic Resource
    Electronic Resource
    On the possibility of using dark magneto-optical lattices to achieve Bose condensation of atoms (1998)
    Springer
    Journal of experimental and theoretical physics 86 (1998), S. 1127-1131 
    Details
    ISSN: 1090-6509
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We show that in dark magneto-optical lattices, effects associated with the Bose statistics of atoms can be observed even at laser cooling temperatures (10−4–10−6 K), which exceed evaporative cooling temperatures in magnetic traps by several orders of magnitude. Quasicondensation occurs, i.e., the wave function is formed over the distances on which atoms are localized near the bottom of a separate potential well. In addition, switching off the magnetic field adiabatically reduces the temperature significantly, as a result of which Bose condensation in the entire volume of the gas can be observed. We propose a configuration of the light and magnetic fields in which the shape of the three-dimensional magneto-optical potential is independent of the phases of the emerging light waves.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.558582
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  • 10
    Electronic Resource
    Electronic Resource
    Elliptic dark states: Explicit invariant form (2000)
    Springer
    Journal of experimental and theoretical physics 91 (2000), S. 67-75 
    Details
    ISSN: 1090-6509
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract An analysis is made of coherent population trapping as a result of resonant interaction of elliptically polarized light with atoms whose energy levels are degenerate with respect to the projection of the angular momentum and are coupled by a dipole transition. Explicit invariant expressions for dark states are obtained in tensor form for all transitions where population trapping occurs. A correspondence is established between the vector of the elliptic polarization and the pair of associated spinors. It is shown that all dark states can be constructed from these spinors by means of a multiple tensor product. For integer values of the angular momenta of the transitions these constructions reduce to spherical functions of a complex variable. As applications analytic expressions are obtained for the dark magneto-optic and geometric potentials, and the change in their profile with increasing angular momenta is analyzed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.1307234
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