Collisional aspects of bosonic and fermionic dipoles in quasi-two-dimensional confining geometries

Fundamental aspects of ultracold collisions between identical bosonic or fermionic dipoles are studied under quasi-two-dimensional (Q2D) confinement. In the strongly dipolar regime, bosonic and fermion species are found to share important collisional properties as a result of the confining geometry, which suppresses the inelastic rates irrespective of the quantum statistics obeyed. A potential negative is that the confinement causes dipole-dipole resonances to be extremely narrow, which could make it difficult to explore Q2D dipolar gases with tunable interactions. Such properties are shown to be universal, and a simple WKB model reproduces most of our numerical results. In order to shed light on the many-body behavior of dipolar gases in Q2D we have analyzed the scattering amplitude and developed an energy-analytic form of the pseudopotentials for dipoles.

Figure 1

Adiabatic potentials for Q2D bosonic (solid) and fermionic (dashed) dipoles (see text).

Figure 2

Elastic and inelastic rates [numerical (dashed) and WKB (dot-dashed)] for bosonic, (a) and (b), and fermionic dipoles, (d) and (e), for $a_{\mathit{ho}}=5r_0$ and $k=0.071r_0^{-1}$. In the strongly dipolar regime, $k{d}_{\ell }\gg 1$, the total elastic rates (thick solid lines) approaches to the eikonal approximation [7] [solid straight line in (a) and (d)] and the inelastic rates are strongly suppressed [(b) and (e)]. (c) and (f) shows the scattering amplitude displaying anisotropy effects (see text).

Figure 3

(a) and (b) Q2D coupling constant, $g_m$, and (c) and (d) its equivalent energy-analytic form, $g_m^a$ [numerical (solid) and WKB (dashed)]. Figure shows “resonant” behavior related to the Ramsauer-Townsend (see text).