Worldline Monte Carlo method for few body nuclear physics

We present a new worldline-based Monte Carlo method for studying non-relativistic few-nucleon systems, which treats nucleons as hardcore bosons and absorbs fermion permutation sign into observables. We show that the fermion sign problem is mild in the few-body sector, allowing for the extraction of bound-state energies for few-nucleon systems by directly evaluating the transfer matrix element $e^{-\beta H}$, where $H$ is the lattice Hamiltonian and $\beta$ is a free real parameter. We apply this method to the Hamiltonian lattice formulation of leading-order pionless effective field theory in finite volume and demonstrate a renormalization procedure for the lattice couplings. Using these lattice parameters, we can reproduce exact lattice results using our algorithm on the smallest lattice size with up to four particles.