Phys. Rev. A 60, R3381 (1999)
Ł. Dobrek, M. Gajda, M. Lewenstein, K. Sengstock, G. Birkl, and W. Ertmer
We demonstrate numerically the efficient generation of vortices in Bose-Einstein condensates (BECs) by using a “phase imprinting” method. The method consists of passing a far-off-resonant laser pulse through an absorption plate with an azimuthally dependent absorption coefficient, imaging the laser beam onto a BEC, and thus creating the corresponding nondissipative Stark-shift potential and condensate phase shift. In our calculations we take into account experimental imperfections. We also propose an interference method to detect vortices by coherently pushing part of the condensate using optically induced Bragg scattering.
Jul 7, 1999
Optical generation of vortices in trapped Bose-Einstein condensates
Phys. Rev. A 64, 043601 (2001)
Ł. Dobrek, M. Gajda, M. Lewenstein, K. Sengstock, G. Birkl, and W. Ertmer
We demonstrate numerically the efficient generation of vortices in Bose-Einstein condensates (BECs) by using a “phase imprinting” method. The method consists of passing a far-off-resonant laser pulse through an absorption plate with an azimuthally dependent absorption coefficient, imaging the laser beam onto a BEC, and thus creating the corresponding nondissipative Stark-shift potential and condensate phase shift. In our calculations we take into account experimental imperfections. We also propose an interference method to detect vortices by coherently pushing part of the condensate using optically induced Bragg scattering.
Ł. Dobrek, M. Gajda, M. Lewenstein, K. Sengstock, G. Birkl, and W. Ertmer
We demonstrate numerically the efficient generation of vortices in Bose-Einstein condensates (BECs) by using a “phase imprinting” method. The method consists of passing a far-off-resonant laser pulse through an absorption plate with an azimuthally dependent absorption coefficient, imaging the laser beam onto a BEC, and thus creating the corresponding nondissipative Stark-shift potential and condensate phase shift. In our calculations we take into account experimental imperfections. We also propose an interference method to detect vortices by coherently pushing part of the condensate using optically induced Bragg scattering.
Jun 1, 1999
Motion of vortex lines in quantum mechanics
Iwo Bialynicki-Birula, Zofia Bialynicka-Birula and Cezary Śliwa
Exact analytic solutions of the time-dependent Schrödinger equation are produced that exhibit a variety of vortex structures. The qualitative analysis of the motion of vortex lines is presented and various types of vortex behavior are identified. Vortex creation and annihilation and vortex interactions are illustrated in the special cases of the free motion, the motion in the harmonic potential, and in the constant magnetic field. Similar analysis of the vortex motions is carried out also for a relativistic wave equation.
Phys. Rev. A 61, 032110 (2000)
Exact analytic solutions of the time-dependent Schrödinger equation are produced that exhibit a variety of vortex structures. The qualitative analysis of the motion of vortex lines is presented and various types of vortex behavior are identified. Vortex creation and annihilation and vortex interactions are illustrated in the special cases of the free motion, the motion in the harmonic potential, and in the constant magnetic field. Similar analysis of the vortex motions is carried out also for a relativistic wave equation.
Phys. Rev. A 61, 032110 (2000)
Apr 5, 1999
Bands of localized electromagnetic waves in random collections of dielectric particles
Turkish Journal of Physics 23, 879 (1999)
Marian RUSEK, Arkadiusz ORŁOWSKI
Anderson localization of electromagnetic waves in random arrays of dielectric cylinders is studied. An effective theoretical approach based on the finite size scaling analysis of transmission is developed. The disordered dielectric medium is modeled by a system of randomly distributed 2D electric dipoles. The appearance of the band of localized waves emerging in the limit of an infinite medium is discovered. It suggests deeper insight into existing experimental and theoretical results.
Marian RUSEK, Arkadiusz ORŁOWSKI
Anderson localization of electromagnetic waves in random arrays of dielectric cylinders is studied. An effective theoretical approach based on the finite size scaling analysis of transmission is developed. The disordered dielectric medium is modeled by a system of randomly distributed 2D electric dipoles. The appearance of the band of localized waves emerging in the limit of an infinite medium is discovered. It suggests deeper insight into existing experimental and theoretical results.
Electromagnetic waves in disordered dielectric media: coupled-dipole model
Turkish Journal of Physics 23, 887 (1999)
Arkadiusz ORŁOWSKI and Marian RUSEK
An effective approach to multiple scattering of electromagnetic waves by disordered dielectric media is developed. A self-consistent energy-conserving coupled-dipole model is used. Applications to the Anderson localization of electromagnetic waves are presented. A complete set of Maxwell's equations is used to describe the propagation of waves and the vector character of the electromagnetic field is fully taken into account.
Arkadiusz ORŁOWSKI and Marian RUSEK
An effective approach to multiple scattering of electromagnetic waves by disordered dielectric media is developed. A self-consistent energy-conserving coupled-dipole model is used. Applications to the Anderson localization of electromagnetic waves are presented. A complete set of Maxwell's equations is used to describe the propagation of waves and the vector character of the electromagnetic field is fully taken into account.
Collective diffusion on hexagonal lattices - repulsive interactions
Surf. Sc. 441, 320 (1999)
ZAŁUSKA-KOTUR M. A. ; KRUKOWSKI S. ; TURSKI Ł. A.
Diffusion of interacting particle on a hexagonal lattice is studied by use of Monte Carlo simulations for a range of densities and temperatures including ordered and disordered phases. The decay of the initially prepared density perturbation is analyzed. Fast, local ordering happens at the beginning of system relaxation and clearly separates as a function of time the much slower global diffusion process. Locally equilibrated density perturbation decays according to the macroscopic diffusion equation, which allows a collective diffusion coefficient to be calculated. The density dependence of the collective diffusion coefficient is shown for several temperatures above and below the critical temperature.
ZAŁUSKA-KOTUR M. A. ; KRUKOWSKI S. ; TURSKI Ł. A.
Diffusion of interacting particle on a hexagonal lattice is studied by use of Monte Carlo simulations for a range of densities and temperatures including ordered and disordered phases. The decay of the initially prepared density perturbation is analyzed. Fast, local ordering happens at the beginning of system relaxation and clearly separates as a function of time the much slower global diffusion process. Locally equilibrated density perturbation decays according to the macroscopic diffusion equation, which allows a collective diffusion coefficient to be calculated. The density dependence of the collective diffusion coefficient is shown for several temperatures above and below the critical temperature.
Mar 5, 1999
New effects in light scattering from cold atoms trapped by harmonic potentials
A. Orlowski, M. Gajda, P. Krekora, R. J. Glauber, and J. Mostowski
First, we study the scattering of light by a single ultracold, trapped atom initially in the ground state of the trapping harmonic potential. We find interesting features of the scattering in the regime where the atomic recoil energy is much larger than the separation between oscillatory trap levels. Although we present the quan-tum mechanical expression for the scattering cross section, special attention is paid to the semiclassical analysis of the process. We show that the major characteristics of the scattering might be deduced from two conservation laws: conservation of energy and momentum in absorption and emission of photon process separately. These conservation laws impose a strong correlation between scattered-light characteristics and the position of the trapped atom at the moment of photon emission. A detailed analysis of the far-off resonance scattering of light from a single atom trapped in an isotropic harmonic potential is also given. In this case, we are able to assume a more realistic, i.e., thermal, initial state of the atomic center of mass. An exact closed-form expression for the differential scattering cross section is derived from a general S-matrix theory of scattering. The possibility of measuring the density–density correlation functions in light-scattering experiments is discussed.
Opt. Spectrosc. 87, 645 (1999)
First, we study the scattering of light by a single ultracold, trapped atom initially in the ground state of the trapping harmonic potential. We find interesting features of the scattering in the regime where the atomic recoil energy is much larger than the separation between oscillatory trap levels. Although we present the quan-tum mechanical expression for the scattering cross section, special attention is paid to the semiclassical analysis of the process. We show that the major characteristics of the scattering might be deduced from two conservation laws: conservation of energy and momentum in absorption and emission of photon process separately. These conservation laws impose a strong correlation between scattered-light characteristics and the position of the trapped atom at the moment of photon emission. A detailed analysis of the far-off resonance scattering of light from a single atom trapped in an isotropic harmonic potential is also given. In this case, we are able to assume a more realistic, i.e., thermal, initial state of the atomic center of mass. An exact closed-form expression for the differential scattering cross section is derived from a general S-matrix theory of scattering. The possibility of measuring the density–density correlation functions in light-scattering experiments is discussed.
Opt. Spectrosc. 87, 645 (1999)
Interference without interference: Directional properties of spontaneous emission
A. Orlowski and W. Zakowicz
A fully quantum-mechanical description of the spontaneous emission from an excited two-level atom placed in front of the two slit interferometer is given. Global modes of the electromagnetic field in a two slit system are derived within the Kirchhoff-Huygens diffraction approximation, serving as a base for the field quantization. The standard Fermi’s golden rule, supplemented by a factor coming from the nontrivial mode structure caused by the presence of the two slit interferometer, is used to show that interference results from the position dependent coupling between the atom and different field modes of the system.
Opt. Spectrosc. 87, 500 (1999)
A fully quantum-mechanical description of the spontaneous emission from an excited two-level atom placed in front of the two slit interferometer is given. Global modes of the electromagnetic field in a two slit system are derived within the Kirchhoff-Huygens diffraction approximation, serving as a base for the field quantization. The standard Fermi’s golden rule, supplemented by a factor coming from the nontrivial mode structure caused by the presence of the two slit interferometer, is used to show that interference results from the position dependent coupling between the atom and different field modes of the system.
Opt. Spectrosc. 87, 500 (1999)
Aug 21, 1998
Anderson localization of electromagnetic waves in confined dielectric media
Phys. Rev. E 59, 3655 (1999)
Marian Rusek and Arkadiusz Orłowski
Anderson localization of electromagnetic waves in random arrays of dielectric cylinders confined within a planar metallic waveguide is studied. The disordered dielectric medium is modeled by a system of randomly distributed two-dimensional electric dipoles. An effective theoretical approach based on the method of images is developed. A clear distinction between isolated localized waves (which exist already in finite media) and the band of localized waves (which appears only in the limit of the infinite medium) is presented. The Anderson localization emerging in the limit of an infinite medium is observed both in finite-size scaling analysis of transmission and in the properties of the spectra of some random matrices.
Marian Rusek and Arkadiusz Orłowski
Anderson localization of electromagnetic waves in random arrays of dielectric cylinders confined within a planar metallic waveguide is studied. The disordered dielectric medium is modeled by a system of randomly distributed two-dimensional electric dipoles. An effective theoretical approach based on the method of images is developed. A clear distinction between isolated localized waves (which exist already in finite media) and the band of localized waves (which appears only in the limit of the infinite medium) is presented. The Anderson localization emerging in the limit of an infinite medium is observed both in finite-size scaling analysis of transmission and in the properties of the spectra of some random matrices.
May 29, 1998
Wehrl's entropy and classification of states
Rep. Math. Phys. 43, 283 (1999)
A. Orłowski
The usefulness of Wehrl's entropy in quantum optics is investigated. Possible applications to the classification of quantum states with respect to their statistical properties are presented. A general variational proof of the observation that for a given average photon number the maximum Wehrl's entropy is attained for thermal states is given.
A. Orłowski
The usefulness of Wehrl's entropy in quantum optics is investigated. Possible applications to the classification of quantum states with respect to their statistical properties are presented. A general variational proof of the observation that for a given average photon number the maximum Wehrl's entropy is attained for thermal states is given.
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