Abstract:
We present a general strategy to solve the notorious fermion
sign problem using cluster algorithms. The method applies to
various systems in the Hubbard model family as well as to
relativistic fermions. Here it is illustrated for
non-relativistic lattice fermions. A configuration of
fermion world-lines is decomposed into clusters that
contribute independently to the fermion permutation sign. A
cluster whose flip changes the sign is referred to as a
meron. Configurations containing meron-clusters contribute 0
to the path integral, while all other configurations
contribute 1. The cluster representation describes the
partition function as a gas of clusters in the zero-meron
sector.