LATTICEEASY: A program for lattice simulations of scalar fields in an expanding universe Original Research Article

We describe a C++ program that we have written and made available for calculating the evolution of interacting scalar fields in an expanding universe. The program is particularly useful for the study of reheating and thermalization after inflation. The program and its full documentation are available on the Web at . In this paper we provide a brief overview of what the program does and what it is useful for.