Rajendra Shrestha

Controlling the momentum current of an off-resonant ratchet

We experimentally investigate the phenomenon of a quantum ratchet created by exposing a Bose-Einstein Condensate to short pulses of a potential which is periodic in both space and time. Such a ratchet is manifested by a directed current of particles, even though there is an absence of a net bias force. We confirm a recent theoretical prediction [M. Sadgrove and S. Wimberger, New J. Phys. \textbf{11}, 083027 (2009)] that the current direction can be controlled by experimental parameters which leave the underlying symmetries of the system unchanged. We demonstrate that this behavior can be understood using a single variable containing many of the experimental parameters and thus the ratchet current is describable using a single universal scaling law.

Magnetic field dependent interactions in an ultracold Li?Yb(3P2) mixture

Magnetic Feshbach resonances have allowed great success in the production of ultracold diatomic molecules from bi-alkali mixtures, but have so far eluded observation in mixtures of alkali and alkaline-earth-like atoms. Inelastic collisional properties of ultracold atomic systems exhibit resonant behavior in the vicinity of such resonances, providing a detection signature. We study magnetic field dependent inelastic effects via atom loss spectroscopy in an ultracold heteronuclear mixture of alkali 6Li in the ground state and alkaline-earth-like 174Yb in an excited electronic metastable state (3P2, ). We observe a variation of the interspecies inelastic two-body rate coefficient by nearly one order of magnitude over a 100–520 G magnetic field range. By comparing to ab initio calculations we link our observations to interspecies Feshbach resonances arising from anisotropic interactions in this novel collisional system.

Photoassociative production of ultracold heteronuclearYbLi*molecules

We report on the production of ultracold heteronuclear YbLi* molecules in a dual-species magneto-optical trap by photoassociation (PA). The formation of the electronically excited molecules close to dissociation was observed by trap loss spectroscopy. We find 4 rovibrational states within a range of

Dynamical tunneling of a Bose-Einstein condensate in periodically driven systems.

250\,

Hamiltonian Ratchets with Ultra‐Cold Atoms

GHz below the Yb(

A COLD-ATOM RATCHET INTERPOLATING BETWEEN CLASSICAL AND QUANTUM DYNAMICS

^1S_0

Fidelity of the quantum δ-kicked accelerator

) + Li(

Formation of LiYb Molecules by Photoassocation

^2P_{1/2}

Feshbach and Photoassociation Resonances in an Ultracold Lithium-Ytterbium Mixture

) asymptote and observe isotopic PA line shifts in mixtures of

Field dependent studies of inelastic scattering properties in an ultracold mixture of lithium and metastable ytterbium

^6