title: Rounding of first order transitions in low-dimensional quantum systems with quenched disorder.
abstract: We prove that the addition of an arbitrarily small random perturbation to a quantum spin system rounds a first-order phase transition in the conjugate order parameter in d < or = 2 dimensions, or for cases involving the breaking of a continuous symmetry in d < or = 4. This establishes rigorously for quantum systems the existence of the Imry-Ma phenomenon which for classical systems was proven by Aizenman and Wehr.
authors.affiliation: Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854-8019, USA. rafaelgr@physics.rutgers.edu
authors.forename: Rafael L
authors.initials: RL
authors.lastname: Greenblatt
authors.forename: Michael
authors.initials: M
authors.lastname: Aizenman
authors.forename: Joel L
authors.initials: JL
authors.lastname: Lebowitz