Extended Two-Channel Kondo Phase of a Rotational Quantum Defect in a Fermi Gas

E Fuh Chuo,K Ballmann,L Borda,J Kroha

doi:10.1088/1742-6596/568/1/012007

Abstract

We show by numerical renormalization group calculations that a quantum defect with a two-dimensional rotational degree of freedom, immersed in a bath of fermionic particles with angular momentum scattering, exhibits an extended 2CK phase without fine-tuning of parameters. It is stabilized by a correlation effect which causes the states with angular momentum m=±1 to be the lowest energy states of the defect. This level crossing with the noninteracting m = 0 ground state is signaled by a plateau in the temperature-dependent impurity entropy at S(T) = kB ln 2, before the 2CK ground state value S(0) = kB In is reached.

Highlights

The two-channel Kondo (2CK) effect has intrigued condensed matter physicists ever since the problem has been formulated by Nozieres and Blandin in 1980 [1]
We show by exact numerical renormalization group calculations that a quantum defect with a two-dimensional rotational degree of freedom, immersed in a bath of fermionic particles with angular momentum scattering, exhibits an extended 2CK phase without finetuning of parameters
This level crossing with the non-interacting m = 0 ground state is signaled by a plateau in the temperature-depen√dent impurity entropy at S(T ) = kB ln 2, before the 2CK ground state value S(0) = kB ln 2 is reached

Summary

Introduction

The two-channel Kondo (2CK) effect has intrigued condensed matter physicists ever since the problem has been formulated by Nozieres and Blandin in 1980 [1]. We show by exact numerical renormalization group calculations that a quantum defect with a two-dimensional rotational degree of freedom, immersed in a bath of fermionic particles with angular momentum scattering, exhibits an extended 2CK phase without finetuning of parameters.

Results

Conclusion