Ultracold quantum dynamics: spin-polarized K + K_2 collisions with three identical bosons or fermions

G. Quéméner (1) , P. Honvault (1) , Jean-Michel Launay (1) , P. Soldan , D. E. Potter , J. M. Hutson

1 PALMS - Physique des atomes, lasers, molécules et surfaces

We have developed a new potential energy surface for spin-polarized K($^2$S) + K$_{2}(^3\Sigma^+_u)$ collisions and carried out quantum dynamical calculations of vibrational quenching at low and ultralow collision energies for both bosons $^{39}$K and $^{41}$K and fermions $^{40}$K. At collision energies above about 0.1 mK the quenching rates are well described by a classical Langevin model, but at lower energies a fully quantal treatment is essential. We find that for the low initial vibrational state considered here ($v=1$), the ultracold quenching rates are {\it not} substantially suppressed for fermionic atoms. For both bosons and fermions, vibrational quenching is much faster than elastic scattering in the ultralow-temperature regime. This contrasts with the situation found experimentally for molecules formed via Feshbach resonances in very high vibrational states.

Domaines: Autre [cond-mat.other]

G. Quéméner, P. Honvault, Jean-Michel Launay, P. Soldan, D. E. Potter, et al.. Ultracold quantum dynamics: spin-polarized K + K_2 collisions with three identical bosons or fermions. Physical Review A : Atomic, molecular, and optical physics [1990-2015], 2005, 71, pp.0327722. ⟨hal-00136010⟩