title: Measurement-noise maximum as a signature of a phase transition.
abstract: We propose that a maximum in measurement noise can be used as a signature of a phase transition. As an example, we study the energy and magnetization noise spectra associated with first- and second-order phase transitions by using Monte Carlo simulations of the Ising model and 5-state Potts model in two dimensions. For a finite size system, the total noise power and the low frequency white noise S(f<f(knee)) increase as T(c) is approached. In the thermodynamic limit, S(f<f(knee)) diverges but f(knee)-->0 and the total noise power vanishes. f(-1)(knee) is approximately the equilibration time.
authors.affiliation: Department of Physics and Astronomy, University of California, Irvine, Irvine, California 92697, USA.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Chen
authors.forename: Clare C
authors.initials: CC
authors.lastname: Yu