Moment asymptotics for multitype branching random walks in random environment
Abstract
We study a discrete time multitype branching random walk on a finite space with finite set of types. Particles follow a Markov chain on the spatial space whereas offspring distributions are given by a random field that is fixed throughout the evolution of the particles. Our main interest lies in the averaged (annealed) expectation of the population size, and its long-time asymptotics. We first derive, for fixed time, a formula for the expected population size with fixed offspring distributions, which is reminiscent of a Feynman-Kac formula. We choose Weibull-type distributions with parameter for the upper tail of the mean number of type particles produced by an type particle. We derive the first two terms of the long-time asymptotics, which are written as two coupled variational formulas, and interpret them in terms of the typical behavior of the system.
Cite
@article{arxiv.1310.7770,
title = {Moment asymptotics for multitype branching random walks in random environment},
author = {Onur Gün and Wolfgang König and Ozren Sekulović},
journal= {arXiv preprint arXiv:1310.7770},
year = {2013}
}