  We present a systematic ab initio study of clustering in hot dilute nuclear
matter using nuclear lattice effective field theory with an SU(4)-symmetric
interaction. We introduce a method called light-cluster distillation to
determine the abundances of dimers, trimers, and alpha clusters as a function
of density and temperature. Our lattice results are compared with an ideal gas
model composed of free nucleons and clusters. Excellent agreement is found at
very low density, while deviations from ideal gas abundances appear at
increasing density due to cluster-nucleon and cluster-cluster interactions. In
addition to determining the composition of hot dilute nuclear matter as a
function of density and temperature, the lattice calculations also serve as
benchmarks for virial expansion calculations, statistical models, and transport
models of fragmentation and clustering in nucleus-nucleus collisions.
