We study symmetric nuclear matter using bare nucleon-nucleon (
NN) interactions with the finite particle-number approach within finite cubic boxes. Due to the
NN correlations originating from the bare
NN interaction, two nucleons can be excited to the high-momentum region, leading to the increase of the kinetic energy in nuclear matter. We further consider the spin excitations in the nucleon pairs, where the spins of the two nucleons are changed, and this excitation is important for the tensor correlation. The unitary correlation operator method (UCOM) is used to treat the short-range correlation. The tail correction coming from the neighboring boxes is also included. We demonstrate the contributions of various excitations of nucleon pairs as well as the tail correction to the total energy at normal density. We also discuss the effects of UCOM and correlated nucleon pairs on the density dependence of the total energy. We calculate the equations of state of symmetric nuclear matter using two kinds of the Argonne potentials and the results agree with those from other many-body theories. The density dependences of the Hamiltonian components are also shown.
Dense nucleonic matter is of vital importance for understanding compact stars and inferring the transition into deconfined quark phase. We present ab initio exact calculations of infinite nucleonic matter with the state-of-the-art full configuration-interaction quantum Monte Carlo method, enabling us to rigorously benchmark many-body methods and assess the degree to which the nucleonic matter is correlated. Our method has been numerically validated against exact diagonalization within a small model space. Calculations of nucleonic matter using chiral nuclear forces reveal that symmetric nuclear matter is strikingly strongly correlated, raising questions on previous ab initio calculations of nuclear matter with many-body expansion truncations and offering insights into simultaneous descriptions of finite nuclei and infinite nucleonic matter from first principles.
Ground-state properties in a model quantum field theory are calculated by stochastic evaluation of a path integral representation of the many-body propagator. The model consists of nonrelativistic nucleons coupled to vector and scalar mesons in one spatial dimension. Binding energies and density distributions are calculated for bound states of up to twenty nucleons. The binding energy as a function of density, the nucleon-nucleon correlation function, and the meson-meson correlation function are evaluated in nuclear matter. Exact ground-state solutions to the full field theory are shown to differ relatively little from those of the potential theory corresponding to the static limit. The exact solutions differ substantially from those of the mean-field (Hartree) approximation, but are quite similar to those obtained in the Hartree-Fock approximation.NUCLEAR STRUCTURE Meson-nucleon field theory. Monte Carlo solution. Nuclear matter.