Cancellation time for correlated random walkers

Fernando Arias de Saavedra (1) , Malvin H Kalos (2) , Francesco Pederiva (3)

1 Fisica Atomica, Molecular y Nuclear
2 LLNL - Lawrence Livermore National Laboratory
3 Fisica

We have studied the dynamics of the correlated diffusion of pairs of random walkers of opposite signs. The use of populations of such pairs has been proposed for the Monte Carlo treatment of many-fermion systems, where the possibility of their cancellation might prevent the characteristic decay of signal--to--noise ratio. For four model systems-- free fermions, the harmonic oscillator, an N-body system of attractive and repulsive harmonic forces, and an extensive system interacting by Poschl-Teller potentials-- we have explored analytically and by computation the behavior of the time to cancellation as a function of initial conditions and, equally important, as a function of system size. We find that for these systems the computational efficiency does not decay either with large imaginary time or with large N.

Mots clés: Physical Sciences

Domaines: Matière Condensée [cond-mat]

Fernando Arias de Saavedra, Malvin H Kalos, Francesco Pederiva. Cancellation time for correlated random walkers. Molecular Physics, 2011, pp.1. ⟨10.1080/00268976.2011.604647⟩. ⟨hal-00722800⟩