630 research outputs found
Coupling between internal spin dynamics and external degrees of freedom in the presence of colored noise
We observe asymmetric transition rates between Zeeman levels (spin-flips) of
magnetically trapped atoms. The asymmetry strongly depends on the spectral
shape of an applied noise. This effect follows from the interplay between the
internal states of the atoms and their external degrees of freedom, where
different trapped levels experience different potentials. Such insight may
prove useful for controlling atomic states by the introduction of noise, as
well as provide a better understanding of the effect of noise on the coherent
operation of quantum systems.Comment: 5 pages, 4 figures; accepted to PR
Analysis of a Magnetically Trapped Atom Clock
We consider optimization of a rubidium atom clock that uses magnetically
trapped Bose condensed atoms in a highly elongated trap, and determine the
optimal conditions for minimum Allan variance of the clock using microwave
Ramsey fringe spectroscopy. Elimination of magnetic field shifts and
collisional shifts are considered. The effects of spin-dipolar relaxation are
addressed in the optimization of the clock. We find that for the interstate
interaction strength equal to or larger than the intrastate interaction
strengths, a modulational instability results in phase separation and symmetry
breaking of the two-component condensate composed of the ground and excited
hyperfine clock levels, and this mechanism limits the clock accuracy.Comment: 11 pages, 6 figures. Accepted for publication in Phys. Rev.
One-mirror Fabry-Perot and one-slit Young interferometry
We describe a new and distinctive interferometry in which a probe particle
scatters off a superposition of locations of a single free target particle. In
one dimension, probe particles incident on superposed locations of a single
"mirror" can interfere as if in a Fabry-Perot interferometer; in two
dimensions, probe particles scattering off superposed locations of a single
"slit" can interfere as if in a two-slit Young interferometer. The condition
for interference is loss of orthogonality of the target states and reduces, in
simple examples, to transfer of orthogonality from target to probe states. We
analyze experimental parameters and conditions necessary for interference to be
observed.Comment: 5 pages, 2 figures, RevTeX, submitted to PR
Observation of decoherence with a movable mirror
Recently it has been proposed to use parity as a measure of the mechanism
behind decoherence or the transformation from quantum to classical. Here, we
show that the proposed experiment is more feasible than previously thought, as
even an initial thermal state would exhibit the hypothesized symmetry breaking.Comment: Proceedings of the Lake Garda "quantum puzzles" conferenc
A Pulse Shaping Algorithm of a Coherent Matter Wave. Controlling Reaction Dynamics
A pulse shaping algorithm for a matter wave with the purpose of controlling a
binary reaction has been designed. The scheme is illustrated for an Eley-Rideal
reaction where an impinging matter-wave atom recombines with an adsorbed atom
on a metal surface. The wave function of the impinging atom is shaped such that
the desorbing molecule leaves the surface in a specific vibrational state.Comment: 4 pages, 5 figure
Time-Averaged Adiabatic Potentials: Versatile traps and waveguides for ultracold quantum gases
We demonstrate a novel class of trapping potentials, time-averaged adiabatic
potentials (TAAP) which allows the generation of a large variety of traps and
waveguides for ultracold atoms. Multiple traps can be coupled through
controllable tunneling barriers or merged altogether. We present analytical
expressions for pancake-, cigar-, and ring- shaped traps. The ring-geometry is
of particular interest for guided matter-wave interferometry as it provides a
perfectly smooth waveguide of controllable diameter, and thus a tunable
sensitivity of the interferometer.Comment: 5 pages, 3 figure
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