Finite-time and finite-size scalings in the evaluation of   large-deviation functions: Analytical study using a birth-death process
  The Giardin\`a-Kurchan-Peliti algorithm is a numerical procedure that uses population dynamics in order to calculate large deviation functions associated to the distribution of time-averaged observables. To study the numerical errors of this algorithm, we explicitly devise a stochastic birth-death process that describes the time evolution of the population probability. From this formulation, we derive that systematic errors of the algorithm decrease proportionally to the inverse of the population size. Based on this observation, we propose a simple interpolation technique for the better estimation of large deviation functions. The approach we present is detailed explicitly in a two-state model. 
Takahiro Nemoto and Esteban Guevara Hidalgo and Vivien Lecomte
cond-mat.stat-mech