Abstract
The remarkable progress in manipulating cold atoms by an optical potential and thereby avoiding the use of magnetic field opens the way to access and study the spectacular physics of the over-screened Kondo effect. Its realization in electronic systems is notoriously elusive. We suggest a combination of harmonic and lattice potentials and show that the feasibility of realizing over-screened Kondo effect in ultra-cold Fermi gas of atoms with spin s ≥ 3/2 in the presence of a localized magnetic impurity atom is proved realistic. Specifying (as a mere example), to a system of ultra cold 22Na Fermi gas and a trapped 6Li impurity, the mechanism of exchange interaction between the Na and Li atoms is elucidated and the exchange constant is found to be positive (antiferromagnetic). The corresponding exchange Hamiltonian is derived, and the Kondo temperature is estimated at the order of 500 nK. Within a weak-coupling renormalization group scheme, it is shown that the coupling renormalizes to the non-Fermi liquid fixed point. An observable displaying multi-channel features even in the weak coupling regime is the impurity magnetization that is negative for T ≫ TK and becomes positive with decreasing temperature.
Coffee and tea will be served 20 minutes prior to the seminar.