Asymptotic dynamics of breathers in Fermi-Pasta-Ulam chains

Abstract

We carry out a numerical study of the asymptotic dynamics of breathers in finite Fermi-Pasta-Ulam chains at zero and nonzero temperatures. While at zero temperature such breathers remain essentially stationary and decay extremely slowly over wide parameter ranges, thermal fluctuations tend to lead to breather motion and more rapid decay. In both cases the decay is essentially exponential over long time intervals.