Exact Partition Functions Of A Polymer On A Square Lattice Up To Chain Length 38

Collapse transition of the lattice polymer on a square lattice is studied by calculating the exact partition functions up to chain length 38; they are obtained by enumerating the number of possible conformations for each energy value. We observe that the locus of partition function zeros approaches the positive real axis as the chain length increases, providing evidence of the collapse transition. The crossover exponent and the transition temperature are estimated from the scaling behavior of the first partition function zeros with increasing chain length.