The universal three-body dynamics in ultra-cold binary Fermi and Fermi-Bose mixtures is studied. Two identical fermions of the mass
m and a particle of the mass
m1 with the zero-range two-body interaction in the states of the total angular momentum L=1 are considered. Using the boundary condition model for the s-wave interaction of different particles, both eigenvalue and scattering problems are treated by solving hyper-radial equations, whose terms are derived analytically. The dependencies of the three-body binding energies on the mass ratio
m/m1 for the positive two-body scattering length are calculated; it is shown that the ground and excited states arise at
m/m1gelambda1approx8.17260 and
m/m1gelambda2approx12.91743, respectively. For
m/m1altlambda1 and
m/m1altlambda2, the relevant bound states turn to narrow resonances, whose positions and widths are calculated. The 2 + 1 elastic scattering and the three-body recombination near the three-body threshold are studied and it is shown that a two-hump structure in the mass-ratio dependencies of the cross sections is connected with arising of the bound states.
The universal three-body dynamics in ultra-cold binary Fermi and Fermi–Bose mixtures is studied. Two identical fermions of mass m and a particle of mass m 1 with the zero-range two-body interaction in states of total angular momentum L = 1 are considered. Using the boundary condition model for the s -wave interaction of different particles, both eigenvalue and scattering problems are treated by solving hyper-radial equations, whose terms are derived analytically. The dependences of the three-body binding energies on the mass-ratio m / m 1 for the positive two-body scattering length are calculated; it is shown that the ground and excited states arise at m / m 1 ⩾ λ 1 ≈ 8.172 60 and m / m 1 ⩾ λ 2 ≈ 12.917 43, respectively. For m / m 1 ≲ λ 1 and m / m 1 ≲ λ 2 , the relevant bound states turn to narrow resonances, whose positions and widths are calculated. The 2 + 1 elastic scattering and the three-body recombination near the three-body threshold are studied, and it is shown that a two-hump structure in the mass-ratio dependences of the cross sections is connected with the rise of the bound states.
Just like Van der Waals gases, quantum gases have some universal thermodynamic properties in deviation to the ideal gas. A dilute quantum fluid of neutral particles has an equation of state involving very few intrinsic parameters. The use of mixtures of two Bose-Einstein condensate allow for the diminution or even cancellation of some terms in the dynamical equation of the fluid. In this context, it was experimentally observed that the physics of an ultra-cold RF-dressed atomic gas (quantum coherent mixture) is much richer than in absence of RF coupling. On the one hand, collective effects usually insignificant - three body elastic interactions - rise and dominate the mean-field properties of the fluid. On the other hand, some beyond-mean field effects - interaction renormalization and quantum vacuum energy - are modified and enhanced. Consequently, We observed novel dynamical properties in potassium 39 RF dressed quantum gases.