arXiv:1608.05899
A method to reduce the rejection rate in Monte Carlo Markov Chains on Ising spin models
Carlo Baldassi
Abstract
We present a method for Monte Carlo sampling on Ising spin systems, introducing a prior on the candidate moves in a Metropolis-Hastings scheme which can significantly reduce the rejection rate. The method can be regarded as an modification of the rejection-free method of Bortz, Kalos and Lebowitz (BKL) [Bortz et al. 1975], which was developed under two assumptions: i) low connectivity, and ii) that the energy shift induced by flipping one spin can only assume a small number of values. Our method employs the same probability distribution for the choice of the moves as BKL, but uses it as a prior in an otherwise standard Metropolis scheme: it is thus not fully rejection-free, but in a wide range of scenarios it is nearly so; moreover, it is easily extensible to more general situations which cannot be treated with the BKL method, in particular when the energy of the system can be written as the sum of two components, only one of which satisfies the assumptions at the basis of the BKL method. We provide two families of examples of such situations: graphs with heterogeneous continuous-valued couplings, and Monte Carlo simulations of quantum spin models in presence of a transverse field in the Suzuki-Trotter formalism. Our code is publicly available [this https URL], and extensible to user-defined models.