165 research outputs found
Squeezing more out of a laser
A laser's intensity can be stabilized by negative feedback from a conventional photodetector. I propose extraction of sub-shot-noise light from the feedback loop at a beam splitter by illuminating the back side of the beam splitter with squeezed-state light
Predicting Future Duration from Present Age: A Critical Assessment
Using a temporal version of the Copernican principle, Gott has proposed a
statistical predictor of future longevity based on present age [J. R. Gott III,
Nature 363, 315 (1993)] and applied the predictor to a variety of examples,
including the longevity of the human species. Though Gott's proposal contains a
grain of truth, it does not have the universal predictive power that he
attributes to it.Comment: 17 pages, standard LaTeX; to be published in Contemporary Physic
Particle-Number-Conserving Bogoliubov Approximation for Bose-Einstein Condensates Using Extended Catalytic States
We encode the many-body wavefunction of a Bose-Einstein condensate (BEC) in
the -particle sector of an extended catalytic state. This catalytic state is
a coherent state for the condensate mode and an arbitrary state for the modes
orthogonal to the condensate mode. Going to a time-dependent interaction
picture where the state of the condensate mode is displaced to the vacuum, we
can organize the effective Hamiltonian by powers of . Requiring the
terms of order to vanish gives the Gross-Pitaevskii equation. Going
to the next order, , we derive equations for the number-conserving
Bogoliubov approximation, first given by Castin and Dum [Phys. Rev. A
, 3008 (1998)]. In contrast to other approaches, ours is well
suited to calculating the state evolution in the Schr\"{o}dinger picture;
moreover, it is straightforward to generalize our method to multi-component
BECs and to higher-order corrections.Comment: 29 pages, 1 figur
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