title: Rounding by disorder of first-order quantum phase transitions: emergence of quantum critical points.
abstract: We give a heuristic argument for disorder rounding of a first-order quantum phase transition into a continuous phase transition. From both weak and strong disorder analysis of the N-color quantum Ashkin-Teller model in one spatial dimension, we find that, for N > or =3, the first-order transition is rounded to a continuous transition and the physical picture is the same as the random transverse field Ising model for a limited parameter regime. The results are strikingly different from the corresponding classical problem in two dimensions where the fate of the renormalization group flows is a fixed point corresponding to N-decoupled pure Ising models.
authors.affiliation: Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA 90095-1547, USA.
authors.forename: Pallab
authors.initials: P
authors.lastname: Goswami
authors.forename: David
authors.initials: D
authors.lastname: Schwab
authors.forename: Sudip
authors.initials: S
authors.lastname: Chakravarty