78,649 research outputs found
Coherent atom-trimer conversion in a repulsive Bose-Einstein condensate
We show that the use of a generalized atom-molecule dark state permits the
enhanced coherent creation of triatomic molecules in a repulsive atomic
Bose-Einstein condensate, with further enhancement being possible in the case
of heteronuclear trimers via the constructive interference between two chemical
reaction channels.Comment: 3 figure
Use of active control systems to improve bending and rotor flapping response of a tilt rotor VTOL airplane
The results are summarized of an analytical study of the use of active control systems for the purpose of reducing the root mean square response of wing vertical bending and rotor flapping to atmospheric turbulence for a tilt-rotor VTOL airplane. Only the wing/rotor assembly was considered so that results of a wind tunnel test program would be applicable in a subsequent phase of the research. The capabilities and limitations of simple single feedback configurations were identified, and the most promising multiloop feedback configurations were then investigated. Design parameters were selected so as to minimize either wing bending or rotor flapping response. Within the constraints imposed by practical levels of feedback gains and complexity and by considerations of safety, reduction in response due to turbulence of the order of 30 to 50 percent is predicted using the rotor longitudinal cyclic and a trailing edge wing flap as control effectors
Quantum Noise in the Collective Abstraction Reaction A+B AB+B
We demonstrate theoretically that the collective abstraction reaction A+B AB+B can be realized efficiently with degenerate bosonic or fermionic
matter waves. We show that this is dominated by quantum fluctuations, which are
critical in triggering its initial stages with the appearance of macroscopic
non-classical correlations of the atomic and molecular fields as a result. This
study opens up a promising new regime of quantum degenerate matter-wave
chemistry.Comment: 4 pages, 3 figures, publishe
Probing the SUSY breaking scale at an collider
If supersymmetry is spontaneously at a low energy scale then the resulting
gravitino would be very light. The interaction strength of the longitudinal
components of such a light gravitino to electron-selectron pair then becomes
comparable to that of electroweak interactions. Such a light gravitino could
modify the cross-section for e^_L e^_R-->\tilde {e}_L\tilde {e}_R from its
MSSM value. Precision measurement of this cross-section could therefore be used
to probe the low energy SUSY breaking scale.Comment: Plain Tex, 7 pages, No figure
Quantum superchemistry in an output coupler of coherent matter waves
We investigate the quantum superchemistry or Bose-enhanced atom-molecule
conversions in a coherent output coupler of matter waves, as a simple
generalization of the two-color photo-association. The stimulated effects of
molecular output step and atomic revivals are exhibited by steering the rf
output couplings. The quantum noise-induced molecular damping occurs near a
total conversion in a levitation trap. This suggests a feasible two-trap scheme
to make a stable coherent molecular beam.Comment: 3 figures, accepted by Phys.Rev.A (submitted to prl in July,
transferred to pra in Sep. and accepted in Nov.
Effect of Image Forces on Polyelectrolyte Adsorption at a Charged Surface
The adsorption of flexible and highly charged polyelectrolytes onto
oppositely charged planar surfaces is investigated by means of Monte Carlo
simulations. The effect of image forces stemming from the dielectric
discontinuity at the substrate interface is considered. The influence, at fixed
polyelectrolyte volume fraction, of chain length and surface-charge density is
also considered. A detailed structural study, including monomer and fluid
charge distributions, is provided. It is demonstrated that image forces can
considerably reduce the degree of polyelectrolyte adsorption and concomitantly
inhibit the charge inversion of the substrate by polyelectrolytes.Comment: 19 pages - 7 eps figs - RevTex 4 - submitted for publicatio
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