Quantum degenerate mixtures of Cs and Yb

Abstract

We report the production of quantum degenerate Bose-Bose mixtures of Cs and Yb with both attractive (Cs + 174 Yb) and repulsive (Cs + 170 Yb) interspecies interactions. Dual-species evaporation is performed in a bichromatic optical dipole trap that combines light at 1070 nm and 532 nm to enable control of the relative trap depths for Cs and Yb. Maintaining a trap which is shallower for Yb throughout the evaporation leads to highly efficient sympathetic cooling of Cs for both isotopic combinations at magnetic fields close to the Efimov minimum in the Cs three-body recombination rate at around 22 G. For Cs + 174 Yb, we produce quantum mixtures with typical atom numbers of N Yb ∼ 5 × 10 4 and N Cs ∼ 5 × 10 3 . We find that the attractive interspecies interaction (characterized by the scattering length a CsYb = −75a 0 ) is stabilized by the repulsive intraspecies interactions. For Cs + 170 Yb, we produce quantum mixtures with typical atom numbers of N Yb ∼ 4 × 10 4 and N Cs ∼ 1 × 10 4 . Here, the repulsive interspecies interaction (a CsYb = 96a 0 ) can overwhelm the intraspecies interactions, such that the mixture sits in a region of partial miscibility.

Spinor Boson Droplets Stabilized By Spin Fluctuations

“…If the equilibrium density does not violate the diluteness assumption of the Bogoliubov theory, an ultradilute, yet liquid-like self-bound droplet emerges. The experimental results of the binary mixture droplets in homonuclear [11,14] and heteronuclear [15] systems are in fair agreement with theories based on Gross-Pitaevskii approximation with local LHY corrections. However, a deeper understanding of such fluctuation stabilized states is desirable for two reasons.…”

“…Recent experiments have realized two classes of ultra- * ayogurt@metu.edu.tr cold droplets: binary mixture droplets [11,14,15] and dipolar droplets [12,16], both of which exhibit a tunable competition among distinct interactions and relatively weak Lee-Huang-Yang (LHY) corrections that can stabilize the residual MF energy. In dipolar droplets, the longrange and short-range interactions compete at the MF level, whereas in the binary mixture droplets, the interspecies and intraspecies short-range interactions combine to form two independent parameters, which individually control the MF and quantum fluctuation corrections.…”

Scattering theory and equation of state of a spherical two-dimensional Bose gas

“…In principle, by limiting the investigation to sufficiently small shells and by properly tuning a quadrupolar magnetic field, it is possible to test our predictions also in standard ground-based laboratories [53]. An alternative promising path for the realization of shell-shaped condensates is offered by bichromatic optical dipole traps [54][55][56], combined with a magnetic field gradient to counterbalance gravity. The variety of possible implementations will allow to investigate our finite-temperature equation of state, and to explore the emergent physics of vortices, long-range interactions, and other nontrivial phenomena [57,58] in a curved quantum gas with the topology of a sphere.…”

Measurement of the tune-out wavelength for Cs133 at 880 nm

“…The measurement of this tune-out wavelength will be useful in future studies of quantum degenerate mixtures involving Cs [68][69][70][71][72]. For example, a stirring beam at this wavelength could be used to create vortices in the atomic species trapped with Cs, without affecting the Cs condensate.…”