Sathwik Krauth 2025
From Werner KRAUTH
K. Sathwik, W. Krauth Thermodynamic integration, fermion sign problem, and real-space renormalization' arXiv2511.12794 (2025)
Abstract We reconsider real-space renormalization for the two-dimensional Ising model, follow- ing the path traced out by Wilson in Sect. VI of his 1975 Reviews of Modern Physics [1]. In that reference, Wilson considerably extended the Kadanoff decimation procedure to- wards a possibly rigorous construction of a real-space scale-invariant hamiltonian. Wil- son’s construction has, to the best of our knowledge, never been fully understood and thus neither reproduced nor generalized. In the present work, we use Monte Carlo sam- pling in combination with thermodynamic integration in order to retrace Wilson’s com- putation for a real-space renormalization with a number of terms in the hamiltonian. We elaborate on the connection of real-space renormalization with the fermion sign prob- lem and discuss to which extent our Monte Carlo procedure actually implements Wilson’s program from half a century ago.
