Correlations in one dimensional quantum impurity problems with an external field
arXiv:cond-mat/9611025 · doi:10.1016/S0550-3213(97)00024-2
Abstract
We study response functions of integrable quantum impurity problems with an external field at $T=0$ using non perturbative techniques derived from the Bethe ansatz. We develop the first steps of the theory of excitations over the new, field dependent ground state, leading to renormalized (or ``dressed'') form-factors. We obtain exactly the low frequency behaviour of the dynamical susceptibility $Ï''(Ï)$ in the double well problem of dissipative quantum mechanics (or equivalently the anisotropic Kondo problem),and the low frequency behaviour of the AC noise $S_t(Ï)$ for tunneling between edges in fractional quantum Hall devices. We also obtain exactly the structure of singularities in $Ï''(Ï)$ and $S_t(Ï)$. Our results differ significantly from previous perturbative approaches.
harvmac, epsf, 37pgs, 2figs. modified some references