Dresden 2003 – scientific programme

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TT: Tiefe Temperaturen

TT 22: Metall-Isolator-Überg
änge in Quantensystemen II

TT 22.7: Talk

Friday, March 28, 2003, 11:45–12:00, HSZ301

Universality class of the insulator-fractionalized insulator transition — •Flavio Nogueira¹ and Asle Sudbø² — ¹Institut für Theoretische Physik, Freie Universtität Berlin — ²Department of Physics, Norwegian University of Science and Technology

Boson systems in 2+1 dimensions exhibiting fractionalized phases are equivalent to a compact Abelian Higgs (CAH) model in the adjoint representation. In such a system the transition from a Mott-insulating phase to a fractionalized insulator is like a deconfinement transition in the corresponding gauge theory. We discuss the universality class and phase diagram of this transition. The critical exponents are obtained from a large-scale Monte Carlo simulation. In a large region near the critical line we obtain Ising exponents. There is a region in the phase diagram where the exponents are continuosly varying before entering a XY regime. This is related to a line of fixed points in the corresponding renormalization group phase diagram. [Reference: A. Sudbø, E. Smøorgrav, J. Smiseth, F.S. Nogueira, and J. Hove, Phys. Rev. Lett. 89, 226403 (2002)]