Applying the Worldvolume Hybrid Monte Carlo method to the two-dimensional Hubbard model

The Worldvolume Hybrid Monte Carlo (WV-HMC) method~[arXiv:2012.08468] is a low-cost algorithm that solves the sign problem without introducing the ergodicity problem. We apply the method to the Hubbard model on a two-dimensional spatial lattice, which can also be regarded as a prototype of QCD at finite density. We first explain the basic algorithms to treat fermion determinants in the WV-HMC method, and then show the computational cost scaling that varies depending on the choice of solver. We also compare the obtained results of observables with those using two other major numerical methods: the ALF (Algorithms for Lattice Fermions) and the Tensor Renormalization Group.