Results 1 - 10 of 18879
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[en] In some exotic nuclei, the Pauli principle forces the progressively added valence nucleon(s) to penetrate the classically forbidden region outside an already saturated core, resulting in a longer than usual tail of the wave function. This enhances the matter radius of the nucleus and provides an extended density distribution. Such nuclei are called halo nuclei and have been a hot topic of interest in the 'island of inversion' in recent times. Characterized by small single particle orbital angular momentum configurations (ℓ = 0, 1), they are weakly bound, with only one or two bound states below the breakup threshold. Hence, the role and the effects of the continuum become vital in their study. Techniques of continuum discretization are then required to explore the behavior of these nuclei and study their various observables to better understand their structure and reaction properties
[en] Nuclei in the vicinity of doubly-magic nucleus "2"0"8Pb with several valence nucleons provide an opportunity to study the interplay between single particle and collective states. Beyond the N = 126 shell closure, nuclear shape changes from spheroidal to mainly quadrupole and octupole deformed shapes. It has been observed that octupole collectivity enhances in comparison to quadrupole collectivity in the nuclei around N = 130. In the present work, preliminary results in the context of "2"1"6Fr have been reported
[en] The process of Zeeman laser cooling of 85Rb atoms in a new scheme employing a transverse magnetic field has been experimentally studied. Upon cooling, the average velocity of atoms was 12 m/s at a beam intensity of 7.2 x 1012 s-1 and an atomic density of 4.7 x 1010 cm-3
[en] An atomic fountain with 85Rb cold atoms is reported. A series of time-of-flight signals is obtained, and the measured temperature of the cold atomic cloud is about 2.4 μK. It will have potential new applications in the precise measurement of fundamental constants and the proof of the Einstein's equivalence principle. (atomic and molecular physics)
[en] We demonstrate a technique to measure hyperfine structure using a frequency-stabilized diode laser in an acoustic-optic modulator locked to the frequency difference between two hyperfine peaks. We use this technique to measure hyperfine intervals in the 5P3/2 state of 85Rb and obtain a precision of 20 kHz. VNa extract values for the magnetic-dipole coupling constant A = 25.038(5) MHz and the electric-quadrupole coupling constant B 26.011(22) MHz. These values are a. significant improvement over previous results. (authors)
[en] The collapse experiment of a 85Rb Bose-Einstein Condensate [E.A. Donley, et al., Nature 412 (2001) 295] is studied by numerical simulation. We show that the time delay before collapsing observed in the experiment depends not only on the interaction strength parameters but also on the collective motion before being tuned to collapse. We also qualitatively discussed two necessary mechanisms for beyond mean-field theories on collapsing phenomena
[en] We demonstrate the first guiding of cold atoms through a 88 mm long piece of photonic band gap fiber. The guiding potential is created by a far-off resonance dipole trap propagating inside the fiber with a hollow core of 12 μm. We load the fiber from a dark spot 85Rb magneto-optical trap and observe a peak flux of more than 105 atoms s-1 at a velocity of 1.5 m s-1. With an additional reservoir optical dipole trap, a constant atomic flux of 1.5 x 104 atoms s-1 is sustained for more than 150 ms. These results open up interesting possibilities to study nonlinear light-matter interaction in a nearly one-dimensional geometry and pave the way for guided matter wave interferometry.
[en] We present apparatus and methods for laser cooling and trapping of single rubidium-85 atoms. The setup consists of a magneto-optical trap and identical optical microtraps lined up by using a programmable acousto-optic defector. The apparatus designs and systematic arrangement are described in conjunction with the limitations of the techniques and the scope for future improvement. Individual control over the position and power of each trap attained in our work is the key to addressable and scalable quantum system. (paper)
[en] In a recent experiment at JILA [E. A. Donley et al., Nature (London) 417, 529 (2002)] an initially pure condensate of 85Rb atoms was exposed to a specially designed time-dependent magnetic-field pulse in the vicinity of a Feshbach resonance. The production of additional components of the gas as well as their oscillatory behavior have been reported. We apply a microscopic theory of the gas to identify these components and determine their physical properties. Our time-dependent studies allow us to explain the observed dynamic evolution of all fractions, and to identify the physical relevance of the pulse shape. Based on ab initio predictions, our theory strongly supports the view that the experiments have produced a molecular condensate
[en] We report on a detailed measurement of the enhanced absorption Hanle effect resonances in 85Rb. The effect was analysed with an experimental setup allowing for the control of each magnetic field component within 1 mG. The characterization deals with the dependence of resonances, observed under different magnetic field conditions, on the frequency, intensity and polarization of the exciting radiation field. An analytic model that precisely describes the resonance behaviour is discussed.