Parrondo games with spatial dependence and a related spin system, II
Abstract
Let game B be Toral's cooperative Parrondo game with (one-dimensional) spatial dependence, parameterized by N (3 or more) and p0,p1,p2,p3 in [0,1], and let game A be the special case p0=p1=p2=p3=1/2. Let muB (resp., mu(1/2,1/2)) denote the mean profit per turn to the ensemble of N players always playing game B (resp., always playing the randomly mixed game (1/2)(A+B)). In previous work we showed that, under certain conditions, both sequences converge and the limits can be expressed in terms of a parameterized spin system on the one-dimensional integer lattice. Of course one can get similar results for mu(gamma,1-gamma) corresponding to gamma A+(1-gamma)B for 0<gamma<1. In this paper we replace the random mixture with the nonrandom periodic pattern Ar Bs, where r and s are positive integers. We show that, under certain conditions, mu[r,s], the mean profit per turn to the ensemble of N players repeatedly playing the pattern Ar Bs, converges to the same limit that mu(gamma,1-gamma) converges to, where gamma:=r/(r+s). For a particular choice of the probability parameters, namely p0=1, p1=p2 in (1/2,1), and p3=0, we show that the Parrondo effect (i.e., muB is nonpositive and mu[r,s] is positive) is present if and only if N is even, at least when s=1.