Photoassociative cooling and trapping of a pair of interacting atoms

Abstract

We show that it is possible to cool interacting pairs of atoms by a lin ⊥ lin Sisyphus-like laser cooling scheme using counter-propagating photoassociation (PA) lasers. It is shown that the center-of-mass motion (c.m.) of atom pairs can be trapped in molecular spin-dependent periodic potentials generated by the lasers.The proposed scheme is most effective for narrow-line PA transitions. We illustrate this with numerical calculations using fermionic 171 Yb atoms as an example.

Optical cooling of interacting atoms in a tightly confined trap

“…Here we extend our idea of photoassociative cooling of Ref. [24] to two-photon sideband cooling of a tightly confined atom-pair in a trap. In case of an atom or ion (which we generally call a species) in a 1D harmonic trap, its motional states can be characterized by the motional quantum number n and energy E n = (n + 1/2) ω with trap frequency ω.…”

“…To study many-body physics of an interacting atomic gas, particularly to explore quantum degeneracy in an interacting system, it is important to devise new method for cooling, trapping and simultaneously manipulating interaction of atomic gases in different interaction regimes. We have addressed [24] a new method by which it is possible to optically cool and trap an interacting pair of atoms.…”

“…Recently, we have proposed a novel scheme for photoassociative cooling and trapping (PACT) of a pair of atoms whereby one can reduce collisional energy and trap the center-of-mass (CM) motion of the pair [24]. The scheme is based on photoassociative coupling between an excited molecular bound state and a single-channel continuum of states of scattering between two ground state atoms.…”

“…Thus, it is quite interesting and innovative to ask about the possibility of coherent manipulation of this coupled motion and utilize it to cool and trap the pair of atoms. The basic idea of our proposed PACT method [24] relies on Sisyphus effect using photoassociative transitions. In this case the sub-levels correspond to molecular angular momenta associated with multiple scattering channels of the atom pair having the same asymptotic threshold and the spin-dependent spatial modulation of light shifts occurs in the CM coordinate space.…”

A unified approach to -, - and V-type systems with one continuum

“…So, in the continuum-bound coupled systems where bound-continuum coherence is important, continuum can be an integral part of coherent phenomena or dynamics in this method. For instance, atom-molecule coherence in photo-or magneto-association of cold atoms (15 ) and Rabi oscillations between atomic and molecular states (16 ) arise due to continuum-bound coherence.…”