Bosons Bound in Strong Potentials

Javier von Stecher

P. M. A. Mestrom, V. E. Colussi, T. Secker +1 more

The elastic scattering properties of three bosons at low energy enter the many-body description of ultracold Bose gases via the three-body scattering hypervolume $D$. We study this quantity for identical bosons that interact via a pairwise finite-range potential. Our calculations cover the regime from strongly repulsive potentials towards attractive potentials supporting multiple two-body bound states and are consistent with the few existing predictions for $D$. We present a numerical confirmation of the universal predictions for $D$ in the strongly interacting regime, where Efimov physics dominates, for a local nonzero-range potential. Our findings highlight how $D$ is influenced by three-body quasibound states with strong $d$-wave or $g$-wave characteristics in the weakly interacting regime.

A. P. Young

S. Rudin

For the bound state of three identical lattice bosons interacting via attractive potentials (with strength U, range r, and repulsive core ${U}_{0}$) we investigate how its mass depends on U for large U. We find that the mobility of this bound complex depends strongly on r and that for a nearest-neighbor interaction (r=1) it may depend strongly on ${U}_{0}$.

Luca Salasnich

Eugene B. Kolomeisky, Joseph P. Straley, Ryan M. Kalas

We analyze the ground-state properties of an artificial atom made out of repulsive bosons attracted to a center for the case that all the interactions are short ranged. Such bosonic atoms could be created by optically trapping ultracold particles of alkali-metal vapors; we present the theory describing how their properties depend on experimentally adjustable strength of ``nuclear'' attraction and interparticle repulsion. The binding ability of the short-range potential increases with space dimensionality, only a limited number of particles can be bound in one dimension, while in two and three dimensions the number of bound bosons can be chosen at will. Particularly in three dimensions we find an unusual effect of enhanced resonant binding: for not very strong interparticle repulsion the equilibrium number of bosons bound to a nuclear potential having a sufficiently shallow single-particle state increases without bound as the nuclear potential becomes less attractive. As a consequence of the competing nuclear attraction enhanced by the Bose statistics and interparticle repulsions, the dependence of the ground-state energy of the atom on the number of particles has a minimum whose position is experimentally tunable. This implies a staircase dependence of the equilibrium number of bound bosons on external parameters which may be used to create a single-atom pipette---an arrangement which allows the transport of atoms into and out of a reservoir, one at a time.