1211.5935 (Junya Otsuki)

Spin-boson coupling in continuous-time quantum Monte Carlo    [PDF]

Junya Otsuki

A vector bosonic field coupled to the electronic spin is treated by means of the continuous-time quantum Monte Carlo method. In the Bose Kondo model with a sub-Ohmic density of states $\rho_{\rm B}(\omega) \sim \omega^{-s}$, two contributions to the spin susceptibility, the Curie term $T^{-1}$ and the term $T^{-s}$ due to bosonic fluctuations, are observed separately. By including the fermionic bath, a quantum phase transition is identified between the Kondo screened state and the bosonic fluctuating state, at which the effective moment and the local Fermi-liquid energy scale vanish. It is demonstrated that the energy scale of the bosonic fluctuation is not affected by the existence of the quantum phase transition.

View original: http://arxiv.org/abs/1211.5935