Abstract
We develop a strong-disorder renormalization group to study quantum phase transitions with continuous 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.
- Received 19 September 2008
DOI:https://doi.org/10.1103/PhysRevB.79.024401
©2009 American Physical Society
Viewpoint
The universal behavior of a disordered system
Published 5 January 2009
The presence of disorder in a quantum many-body system may appear to make an already difficult problem nearly impossible to solve. However, scientists show that the details of the disorder often do not matter, allowing them to describe realistic systems from magnets to superconductors.
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