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.
T. Vojta et al., "Infinite-Randomness Quantum Critical Points Induced by Dissipation," Physical Review B, American Physical Society (APS), Jan 2009.
The definitive version is available at http://dx.doi.org/10.1103/PhysRevB.79.024401
National Science Foundation (U.S.)
University of Missouri Research Board
Keywords and Phrases
Critical Points; Ferromagnetic-Antiferromagnetic Transitions; Renormalisation; Renormalization; Superconducting Transitions; Symmetry
Article - Journal
© 2009 American Physical Society (APS), All rights reserved.