title: Critical behavior and scaling in trapped systems.
abstract: We study the scaling properties of critical particle systems confined by a potential. Using renormalization-group arguments, we show that their critical behavior can be cast in the form of a trap-size scaling, resembling finite-size scaling theory, with a nontrivial trap critical exponent theta, which describes how the correlation length xi scales with the trap size l, i.e., xi approximately l;{theta} at T_{c}. theta depends on the universality class of the transition, the power law of the confining potential, and on the way it is coupled to the critical modes. We present numerical results for two-dimensional lattice gas (Ising) models with various types of harmonic traps, which support the trap-size scaling scenario.
authors: Dipartimento di Fisica dell'Università di Pisa and INFN, I-56127 Pisa, Italy.
authors: Massimo
authors: M
authors: Campostrini
authors: Ettore
authors: E
authors: Vicari