arXiv:0809.2699 · Physical Review B
Infinite-randomness quantum critical points induced by dissipation
Thomas Vojta, Chetan Kotabage, José A. Hoyos
Abstract
We develop a strong-disorder renormalization group to study quantum phase transitions with continuous $O(N)$ symmetry order parameters under the influence of both quenched disorder and dissipation. For Ohmic dissipation, as realized in Hertz's theory of the itinerant antiferromagnetic transition or in the superconductor-metal transition in nanowires, we find the transition to be governed by an exotic infinite-randomness fixed point in the same universality class as the (dissipationless) random transverse-field Ising model. We determine the critical behavior and calculate key observables at the transition and in the associated quantum Griffiths phase. We also briefly discuss the cases of super-Ohmic and sub-Ohmic dissipations.