Finite- and long-range spin-wave free-energy asymptotics for the two-dimensional quantum Heisenberg ferromagnet
This paper proves the leading low-temperature free energy asymptotics for the two-dimensional quantum Heisenberg ferromagnet with power-law exchange interactions, establishing fractional and logarithmically corrected laws for long-range cases and extending Takahashi's quadratic law to kernels with finite second moments, with results supported by Quantum Monte Carlo simulations.