4,441 research outputs found
Observation of Heteronuclear Feshbach Molecules from a Rb - Rb gas
We report on the observation of ultracold heteronuclear Feshbach molecules.
Starting with a Rb BEC and a cold atomic gas of Rb, we utilize
previously unobserved interspecies Feshbach resonances to create up to 25,000
molecules. Even though the Rb gas is non-degenerate we observe a large
molecular conversion efficiency due to the presence of a quantum degenerate
Rb gas; this represents a key feature of our system. We compare the
molecule creation at two different Feshbach resonances with different
magnetic-field widths. The two Feshbach resonances are located at
G and G. We also directly measure the small
binding energy of the molecules through resonant magnetic-field association.Comment: v2 - minor change
Continued fraction representation of the Coulomb Green's operator and unified description of bound, resonant and scattering states
If a quantum mechanical Hamiltonian has an infinite symmetric tridiagonal
(Jacobi) matrix form in some discrete Hilbert-space basis representation, then
its Green's operator can be constructed in terms of a continued fraction. As an
illustrative example we discuss the Coulomb Green's operator in
Coulomb-Sturmian basis representation. Based on this representation, a quantum
mechanical approximation method for solving Lippmann-Schwinger integral
equations can be established, which is equally applicable for bound-, resonant-
and scattering-state problems with free and Coulombic asymptotics as well. The
performance of this technique is illustrated with a detailed investigation of a
nuclear potential describing the interaction of two particles.Comment: 7 pages, 4 ps figures, revised versio
Studying a dual-species BEC with tunable interactions
We report on the observation of controllable spatial separation in a
dual-species Bose-Einstein condensate (BEC) with Rb and Rb.
Interparticle interactions between the different components can change the
miscibility of the two quantum fluids. In our experiments, we clearly observe
the immiscible nature of the two simultaneously Bose-condensed species via
their spatial separation. Furthermore the Rb Feshbach resonance near 155
G is used to change them between miscible and immiscible by tuning the
Rb scattering length. Our apparatus is also able to create Rb
condensates with up to atoms which represents a significant
improvement over previous work
- …