Multichannel interactions of two atoms in an optical tweezer

Abstract

The multichannel Na-Cs interactions are characterized by a series of measurements using two atoms in an optical tweezer, along with a multichannel quantum defect theory (MQDT). The triplet and singlet scattering lengths are measured by performing Raman spectroscopy of the Na-Cs motional states and least-bound molecular state in the tweezer. Magnetic Feshbach resonances are observed for only two atoms at fields which agree well with the MQDT. Our methodology, which promotes the idea of an effective theory of interaction, can be a key step towards the understanding and the description of more complex interactions. The tweezer-based measurements in particular will be an important tool for atom-molecule and molecule-molecule interactions, where high densities are experimentally challenging and where the interactions can be dominated by intra-species processes.

Forming a Single Molecule by Magnetoassociation in an Optical Tweezer

“…We directly measure the population of the relative ground state by interaction shift spectroscopy in a separate experiment, as described in Ref. [35]. We find a relative motional ground-state probability of ∼58%, which combined with hyperfine-state preparation fidelities (Na ∼ 88%, Cs ∼ 96%) is consistent with our molecule conversion efficiency of 45%-50%, depending on experimental conditions [48].…”

“…After the atoms are cooled to their motional ground states, we prepare them in the lowest Zeeman energy level: Na jF ¼ 1; m F ¼ 1i and Cs jF ¼ 3; m F ¼ 3i. This choice of hyperfine channel eliminates the possibility of spin-changing inelastic collisions, which could occur in our previous work [35], and allows production of stable Feshbach molecules.…”

“…Our search for Na-Cs FRs was initially guided by multichannel quantum defect theory, using singlet and triplet scattering lengths previously determined from interaction shift spectroscopy [35]. In the present work, we have developed a coupled-channel model of Na þ Cs.…”

“…Singlet and triplet potential curves were obtained by adjusting the interaction potentials in Ref. [36] to reproduce the binding energy of the least-bound triplet state [35] and the position of the s-wave resonance described below. The adjustment procedures were similar to those used for K þ Cs in Ref.…”

Entanglement and entropy squeezing in the system of two qubits interacting with a two-mode field in the context of power low potentials

“…The two-level atom inside a cavity field is the simplest case of the atom-photon interaction, described by the famous Jaynes-Cummings model (JCM) 1 . Since its introduction, the model has received great attention in the fields of quantum optics and laser physics for both experimental and theoretical studies [2][3][4][5][6][7][8][9][10][11][12][13][14][15] , and this interest is partly due to its apparent simplicity and, most importantly, to its remarkable predictions about the dynamical characteristics of subsystems. This model has come to be an inspiration for a wide range of generalizations inextricably linked to more general situations with realistic circumstances.…”