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

Quantum Noise in the Collective Abstraction Reaction A+B 2→_2\to AB+B

We demonstrate theoretically that the collective abstraction reaction A+B$_2 \to$ 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

Trapping and Cooling a mirror to its quantum mechanical ground state

We propose a technique aimed at cooling a harmonically oscillating mirror to its quantum mechanical ground state starting from room temperature. Our method, which involves the two-sided irradiation of the vibrating mirror inside an optical cavity, combines several advantages over the two-mirror arrangements being used currently. For comparable parameters the three-mirror configuration provides a stiffer trap for the oscillating mirror. Furthermore it prevents bistability from limiting the use of higher laser powers for mirror trapping, and also partially does so for mirror cooling. Lastly, it improves the isolation of the mirror from classical noise so that its dynamics are perturbed mostly by the vacuum fluctuations of the optical fields. These improvements are expected to bring the task of achieving ground state occupation for the mirror closer to completion.Comment: 5 pages, 1 figur

Using a Laguerre-Gaussian beam to trap and cool the rotational motion of a mirror

We show theoretically that it is possible to trap and cool the rotational motion of a macroscopic mirror made of a perfectly reflecting spiral phase element using orbital angular momentum transfer from a Laguerre-Gaussian optical field. This technique offers a promising route to the placement of the rotor in its quantum mechanical ground state in the presence of thermal noise. It also opens up the possibility of simultaneously cooling a vibrational mode of the same mirror. Lastly, the proposed design may serve as a sensitive torsional balance in the quantum regime.Comment: New cavity design, reworked title; to appear in Phys. Rev. Let

A Molecular Matter-Wave Amplifier

We describe a matter-wave amplifier for vibrational ground state molecules, which uses a Feshbach resonance to first form quasi-bound molecules starting from an atomic Bose-Einstein condensate. The quasi-bound molecules are then driven into their stable vibrational ground state via a two-photon Raman transition inside an optical cavity. The transition from the quasi-bound state to the electronically excited state is driven by a classical field. Amplification of ground state molecules is then achieved by using a strongly damped cavity mode for the transition from the electronically excited molecules to the molecular ground state

Limits to phase resolution in matter wave interferometry

We study the quantum dynamics of a two-mode Bose-Einstein condensate in a time-dependent symmetric double-well potential using analytical and numerical methods. The effects of internal degrees of freedom on the visibility of interference fringes during a stage of ballistic expansion are investigated varying particle number, nonlinear interaction sign and strength as well as tunneling coupling. Expressions for the phase resolution are derived and the possible enhancement due to squeezing is discussed. In particular, the role of the superfluid - Mott insulator cross-over and its analog for attractive interactions is recognized.Comment: 10 pages, 9 figure

On the Magic Matrix by Makhlin and the B-C-H Formula in SO(4)

A closed expression to the Baker-Campbell-Hausdorff (B-C-H) formula in SO(4) is given by making use of the magic matrix by Makhlin. As far as we know this is the {\bf first nontrivial example} on (semi-) simple Lie groups summing up all terms in the B-C-H expansion.Comment: Latex ; 11 pages ; 1 figure ; minor changes. To appear in International Journal of Geometric Methods in Modern Physics (vol.4, no.5 or 6), 200

Cavity atom optics and the `free atom laser'

The trap environment in which Bose-Einstein condensates are generated and/or stored strongly influences the way they interact with light. The situation is analogous to cavity QED in quantum optics, except that in the present case, one tailors the matter-wave mode density rather than the density of modes of the optical field. Just as in QED, for short times, the atoms do not sense the trap and propagate as in free space. After times long enough that recoiling atoms can probe the trap environment, however, the way condensates and light fields are mutually influenced differs significantly from the free-space situation. We use as an example the condensate collective atomic recoil laser, which is the atomic matter-wave analog of the free-electron laser.Comment: To be published in a special edition of Optics Communications in honor of the 60th birthday of Marlan Scull