%0 Journal Article
%A Fernández Pérez, Luis Antonio
%A Martín Mayor, Víctor
%A Yllanes, D.
%T Tethered Monte Carlo: computing the effective potential without critical slowing down
%D 2009
%@ 0550-3213
%U https://hdl.handle.net/20.500.14352/45067
%X We present Tethered Monte Carlo, a simple, general purpose method of computing the effective potential of the order parameter (Helmholtz free energy). This formalism is based on a new statistical ensemble, closely related to the micromagnetic one, but with an extended configuration space (through Creutz-like demons). Canonical averages for arbitrary values of the external magnetic field are computed without additional simulations. The method is put to work in the two-dimensional Ising model, where the existence of exact results enables us to perform high precision checks. A rather peculiar feature of our implementation, which employs a local Metropolis algorithm, is the total absence, within errors, of critical slowing down for magnetic observables. Indeed, high accuracy results are presented for lattices as large as L = 1024.
%~