Cold atom coupled to a heat bath in non-Abelian gauge potential: Effect on magnetic moment

Abstract

In this work, we study the effect of non-Abelian gauge potential on the magnetic moment of a cold atom which is linearly coupled to a quantum heat bath through two different coupling schemes: (i) coordinate-coordinate coupling and (ii) momentum-momentum coupling. The bath is modelled as a collection of independent quantum harmonic oscillators. In each coupling scheme, the effect of the non-Abelian magnetic field on magnetic moment are explicitly demonstrated for a U(2) gauge transformation. For both schemes, we show that the magnetic moment has a different expression than that for the Abelian case. We consider two illustrative heat bath spectrum (Ohmic bath and Drude model) to evaluate the magnetic moment in the low temperature limit.