The Experts below are selected from a list of 186 Experts worldwide ranked by ideXlab platform
Paul S. Julienne - One of the best experts on this subject based on the ideXlab platform.
-
multichannel quantum defect theory for slow Atomic Collisions
Physical Review A, 2005Co-Authors: Bo Gao, Eite Tiesinga, Carl J Williams, Paul S. JulienneAbstract:We present a multichannel quantum-defect theory for slow Atomic Collisions that takes advantages of the analytic solutions for the long-range potential and both the energy and angular momentum insensitivities of the short-range parameters. The theory provides an accurate and complete account of scattering processes, including shape and Feshbach resonances, in terms of a few parameters such as the singlet and triplet scattering lengths. As an example, results for $^{23}\mathrm{Na}\ensuremath{-}^{23}\mathrm{Na}$ scattering are presented and compared to close-coupling calculations.
-
effective scattering length model of ultracold Atomic Collisions and feshbach resonances in tight harmonic traps
Physical Review A, 2002Co-Authors: Eric L Bolda, Eite Tiesinga, Paul S. JulienneAbstract:We consider the problem of cold Atomic Collisions in tight traps, where the absolute scattering length may be larger than the trap size. As long as the size of the trap ground state is larger than a characteristic length of the van der Waals potential, the energy eigenvalues can be computed self-consistently from the scattering phase shift for untrapped atoms. By comparing with the exact numerical eigenvalues of the trapping plus interAtomic potentials, we verify that our model gives accurate eigenvalues up to milliKelvin energies for single-channel s-wave scattering of ${}^{23}\mathrm{Na}$ atoms in an isotropic harmonic trap, even when outside the Wigner threshold regime. Our model works also for multichannel scattering, where the scattering length can be made large due to a magnetically tunable Feshbach resonance.
-
Theory of Atomic Collisions at ultracold temperatures
AIP Conference Proceedings, 1991Co-Authors: Paul S. Julienne, Robert W. Heather, Jacques ViguéAbstract:This paper outlines key problems in the theory of Atomic Collisions at ultracold temperatures. Features associated with the unusual energy time and distance scales encountered in ultracold Collisions are described. The molecular physics of excited plus ground state alkali dimers is examined. A quasistatic model is developed to describe collision rates between normal and ultracold temperatures. Mechanisms are proposed for the very different associative ionization rates observed in an optical trap and in optical molasses. (AIP)
Bo Gao - One of the best experts on this subject based on the ideXlab platform.
-
multichannel quantum defect theory for slow Atomic Collisions
Physical Review A, 2005Co-Authors: Bo Gao, Eite Tiesinga, Carl J Williams, Paul S. JulienneAbstract:We present a multichannel quantum-defect theory for slow Atomic Collisions that takes advantages of the analytic solutions for the long-range potential and both the energy and angular momentum insensitivities of the short-range parameters. The theory provides an accurate and complete account of scattering processes, including shape and Feshbach resonances, in terms of a few parameters such as the singlet and triplet scattering lengths. As an example, results for $^{23}\mathrm{Na}\ensuremath{-}^{23}\mathrm{Na}$ scattering are presented and compared to close-coupling calculations.
-
quantum defect theory of Atomic Collisions and molecular vibration spectra
Physical Review A, 1998Co-Authors: Bo GaoAbstract:A quantum-defect theory of Atomic Collisions and molecular vibration spectra is presented. Based on the exact solutions of the Schr\"odinger equation for an attractive ${1/r}^{6}$ potential, the theory provides a systematic interpretation of molecular bound states and atom-atom scattering properties and establishes the relationship between the two. Applications to systems including ${}^{7}{\mathrm{Li}}_{2}$ and ${}^{23}{\mathrm{Na}}_{2}$ are discussed.
Eite Tiesinga - One of the best experts on this subject based on the ideXlab platform.
-
multichannel quantum defect theory for slow Atomic Collisions
Physical Review A, 2005Co-Authors: Bo Gao, Eite Tiesinga, Carl J Williams, Paul S. JulienneAbstract:We present a multichannel quantum-defect theory for slow Atomic Collisions that takes advantages of the analytic solutions for the long-range potential and both the energy and angular momentum insensitivities of the short-range parameters. The theory provides an accurate and complete account of scattering processes, including shape and Feshbach resonances, in terms of a few parameters such as the singlet and triplet scattering lengths. As an example, results for $^{23}\mathrm{Na}\ensuremath{-}^{23}\mathrm{Na}$ scattering are presented and compared to close-coupling calculations.
-
effective scattering length model of ultracold Atomic Collisions and feshbach resonances in tight harmonic traps
Physical Review A, 2002Co-Authors: Eric L Bolda, Eite Tiesinga, Paul S. JulienneAbstract:We consider the problem of cold Atomic Collisions in tight traps, where the absolute scattering length may be larger than the trap size. As long as the size of the trap ground state is larger than a characteristic length of the van der Waals potential, the energy eigenvalues can be computed self-consistently from the scattering phase shift for untrapped atoms. By comparing with the exact numerical eigenvalues of the trapping plus interAtomic potentials, we verify that our model gives accurate eigenvalues up to milliKelvin energies for single-channel s-wave scattering of ${}^{23}\mathrm{Na}$ atoms in an isotropic harmonic trap, even when outside the Wigner threshold regime. Our model works also for multichannel scattering, where the scattering length can be made large due to a magnetically tunable Feshbach resonance.
C. D. Lin - One of the best experts on this subject based on the ideXlab platform.
-
Alignment and orientation in Atomic Collisions
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1994Co-Authors: C. D. Lin, Nobuyuki Toshima, W. FritschAbstract:Abstract Recent experimental and theoretical studies of alignment, orientation and dipole moments of excited states formed in Atomic Collisions for simple systems are reviewed. We also review the studies of the dependence of electron capture cross sections on the magnetic quantum numbers of the initial target states. The propensity rule involving the magnetic quantum numbers in Atomic Collisions is also examined.
-
the semiclassical close coupling description of Atomic Collisions recent developments and results
Physics Reports, 1991Co-Authors: Wolfgang Fritsch, C. D. LinAbstract:Abstract Developments in the semiclassical close-coupling description of Atomic Collisions, in an energy range of roughly 0.1 up to a few hundred keV per nucleon of the projectile, are reviewed with emphasis on recent progress in its application to a wide range of collision phenomena. After a qualitative discussion of the basics of the close-coupling description, we introduce the commonly used basis sets, such as sets of molecular orbitals, Atomic orbitals and pseudostates, which are employed to define the truncated Hilbert space for the time evolution of the electronic wavefunction. It is shown that experimental data for the dominant and subdominant electron transition channels, for collision systems with one or two active electrons, are generally well described by the close-coupling method with moderately sized basis sets. Recent progress in studies of angular-momentum coherences in collisionally excited states illustrates the general reliability of the relative phases of scattering amplitudes from the close-coupling calculations. The limitations of the close-coupling description as well as possible new areas for future applications are also discussed.
Sh Barzanjeh - One of the best experts on this subject based on the ideXlab platform.
-
nonlinear effects of Atomic Collisions on the optomechanical properties of a bose einstein condensate in an optical cavity
Physical Review A, 2013Co-Authors: A Dalafi, M H Naderi, M Soltanolkotabi, Sh BarzanjehAbstract:In this paper, we have investigated theoretically the influence of Atomic Collisions on the behavior of a one-dimensional Bose-Einstein condensate inside a driven optical cavity. We develop the discrete-mode approximation for the condensate taking into account the interband transitions due to the $s$-wave scattering interaction. We show that in the Bogoliubov approximation the atom-atom interaction shifts the energies of the excited modes and also plays the role of an optical parametric amplifier for the Bogoliubov side mode which can affect its normal-mode splitting behavior. On the other hand due to the Atomic Collisions the resonance frequency of the cavity is shifted which leads to the decrease of the number of cavity photons and the depletion of the Bogoliubov mode. Besides, it reduces the effective atom-photon coupling parameter which consequently leads to the decrease of the entanglement between the Bogoliubov mode and the optical field.