Combinatorics for the east model

Abstract

We study the number of configurations in the East model of statistical physics. This may be pictured as sites in a line. The site at zero is always occupied. The site at i0 can only be changed if site i-1 is occupied. If at most n occupied sites are permitted, we establish upper and lower bounds of the form 2n2n!cn where c<1 for the number of possible configurations. © 2001 Academic Press.