Species-selective optical lattices

Fernanda Pinheiro

Xiaodong Bai, Mei Zhang, Jun Xiong +2 more

We investigate the formation of discrete breathers (DBs) and the dynamics of the mixture of two-species Bose-Einstein condensates (BECs) in open boundary optical lattices using the discrete nonlinear Schrödinger equations. The results show that the coupling of intra- and interspecies interaction can lead to the existence of pure single-species DBs and symbiotic DBs (i.e., two-species DBs). Furthermore, we find that there is a selective distillation phenomenon in the dynamics of the mixture of two-species BECs. One can selectively distil one species from the mixture of two-species BECs and can even control dominant species fraction by adjusting the intra- and interspecies interaction in optical lattices. Our selective distillation mechanism may find potential application in quantum information storage and quantum information processing based on multi-species atoms.

Lindsay J. LeBlanc, Joseph H. Thywissen

We examine single-frequency optical schemes for species-selective trapping of ultracold alkali-metal atoms. Independently addressing the elements of a binary mixture enables the creation of an optical lattice for one atomic species with little or no effect on the other. We analyze a ``tune-in'' scheme, using near-resonant detuning to create a strong potential for one specific element. A ``tune-out'' scheme is also developed, in which the trapping wavelength is chosen to lie between two strong transitions of an alkali-metal atom such that the induced dipole moment is zero for that species but is nonzero for any other. We compare these schemes by examining the trap depths and heating rates associated with both. We find that the tune-in scheme is preferable for $\mathrm{Li}\text{\ensuremath{-}}\mathrm{Na}$, $\mathrm{Li}\text{\ensuremath{-}}\mathrm{K}$, and $\mathrm{K}\text{\ensuremath{-}}\mathrm{Na}$ mixtures, while the tune-out scheme is preferable for $\mathrm{Li}\text{\ensuremath{-}}\mathrm{Cs}$, $\mathrm{K}\text{\ensuremath{-}}\mathrm{Rb}$, $\mathrm{Rb}\text{\ensuremath{-}}\mathrm{Cs}$, $\mathrm{K}\text{\ensuremath{-}}\mathrm{Cs}$, and $^{39}\mathrm{K}\text{\ensuremath{-}}^{40}\mathrm{K}$ mixtures. Several applications of species-selective optical lattices are explored, including the creation of a lattice for a single species in the presence of a phononlike background, the tuning of relative effective mass, and the isothermal increase of phase-space density.

Patrick Windpassinger, K. Sengstock

R. Chamakhi, Henning Ahlers, Mourad Telmini +3 more

Long-baseline precision tests based on atom interferometry require drastic control over the initial external degrees of freedom of atomic ensembles to reduce systematic effects. The use of optical lattices (OLs) is a highly accurate method to manipulate atomic states in position and momentum allowing excellent control of the launch in atomic fountains. The simultaneous lattice launch of two atomic species, as required in a quantum test of the equivalence principle, is however problematic due to crosstalk effects. In this article, we propose to selectively address two species of alkalines by applying two OLs at or close to magic-zero wavelengths of the atoms. The proposed scheme applies in general for a pair of species with a vastly different ac Stark shift to a laser wavelength. We illustrate the principle by studying a fountain launch of condensed ensembles of 87 Rb and 41 K initially co-located. Numerical simulations confirm the fidelity of our scheme up to few nm and nm s −1 in inter-species differential position and velocity, respectively. This result is a pre-requisite for the next performance level in precision tests.

Markus Greiner, Simon Fölling