Coqblin-Schrieffer Model for an Ultra-cold Gas of Ytterbium atoms with Metastable States

TL;DR

This paper demonstrates the feasibility of realizing the Coqblin-Schrieffer model in ultracold ytterbium gases, analyzing the exchange interactions, and predicting observable thermodynamic properties relevant for experiments.

Contribution

It introduces a novel implementation of the Coqblin-Schrieffer model using cold ytterbium atoms with metastable states, including the derivation of the Hamiltonian and analysis of exchange interactions.

Findings

Antiferromagnetic exchange between ground and metastable states

Construction of SU(6) symmetric Coqblin-Schrieffer Hamiltonian

Predicted experimentally accessible Kondo temperature

Abstract

Motivated by the impressive recent advance in manipulating cold ytterbium atoms we explore and substantiate the feasibility of realizing the Coqblin-Schrieffer model in a gas of cold fermionic $^{173}$Yb atoms. Making use of different AC polarizabillity of the electronic ground state (electronic configuration $^1S_0$) and the long lived metastable state (electronic configuration $^3P_0$), it is substantiated that the latter can be localized and serve as a magnetic impurity while the former remains itinerant. The exchange mechanism between the itinerant $^1S_0$ and the localized $^3P_0$ atoms is analyzed and shown to be antiferromagnetic. The ensuing SU(6) symmetric Coqblin-Schrieffer Hamiltonian is constructed, and, using the calculated exchange constant $J$, perturbative RG analysis yield the Kondo temperature $T_K$ that is experimentally accessible. A number of thermodynamic measurable observables are calculated in the weak coupling regime $T>T_K$ (using perturbative RG analysis) and in the strong coupling regime $T<T_K$ (employing known Bethe ansatz techniques).