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.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.

arXiv:2209.07810Physical Review CSep 15, 20221 citation

Dispersion energies and excitation parameters in fermion fluids

Chun Wa Wong

Certain physical mechanisms contributing to the Brueckner pair dispersion energy ${W}_{2}^{D}$ are reviewed. This ${W}_{2}^{D}$ is found to appear also in the Iwamoto-Yamada cluster expansion if the same Brueckner state- and momentum-dependent correlation operators are used. It does not appear in the two-body Iwamoto-Yamada energy, however, but in the three-body energy. Up to this point, a Brueckner triplet dispersion energy ${W}_{3}^{D}$ has not yet appeared. This ${W}_{3}^{D}$ depends on a triplet excitation parameter ${\ensuremath{\kappa}}_{3}$, which is calculated using Jastrow correlation functions. We find that ${\ensuremath{\kappa}}_{3}$ is small when ${\ensuremath{\kappa}}_{2}$ is small (\ensuremath{\lesssim} 0.1), and large when ${\ensuremath{\kappa}}_{2}$ is large (\ensuremath{\gtrsim} 0.4). Since ${\ensuremath{\kappa}}_{2}\ensuremath{\approx}0.2$ in nuclear matter, there is hope that both Brueckner and Iwamoto-Yamada expansions converge to the same answer at fairly low orders.NUCLEAR STRUCTURE Fermion fluids, nuclear matter; compared Brueckner and IY expansions; calculated triplet excitation parameter.Certain physical mechanisms contributing to the Brueckner pair dispersion energy ${W}_{2}^{D}$ are reviewed. This ${W}_{2}^{D}$ is found to appear also in the Iwamoto-Yamada cluster expansion if the same Brueckner state- and momentum-dependent correlation operators are used. It does not appear in the two-body Iwamoto-Yamada energy, however, but in the three-body energy. Up to this point, a Brueckner triplet dispersion energy ${W}_{3}^{D}$ has not yet appeared. This ${W}_{3}^{D}$ depends on a triplet excitation parameter ${\ensuremath{\kappa}}_{3}$, which is calculated using Jastrow correlation functions. We find that ${\ensuremath{\kappa}}_{3}$ is small when ${\ensuremath{\kappa}}_{2}$ is small (\ensuremath{\lesssim} 0.1), and large when ${\ensuremath{\kappa}}_{2}$ is large (\ensuremath{\gtrsim} 0.4). Since ${\ensuremath{\kappa}}_{2}\ensuremath{\approx}0.2$ in nuclear matter, there is hope that both Brueckner and Iwamoto-Yamada expansions converge to the same answer at fairly low orders.NUCLEAR STRUCTURE Fermion fluids, nuclear matter; compared Brueckner and IY expansions; calculated triplet excitation parameter.

Physical Review CMay 1, 19773 citations

Collective excitations in nuclear matter

A.G. Sitenko, I.V. Simenog

Nuclear PhysicsApr 1, 19641 citation

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.

Certain physical mechanisms contributing to the Brueckner pair dispersion energy

{W}_{2}^{D}

are reviewed. This

{W}_{2}^{D}

is found to appear also in the Iwamoto-Yamada cluster expansion if the same Brueckner state- and momentum-dependent correlation operators are used. It does not appear in the two-body Iwamoto-Yamada energy, however, but in the three-body energy. Up to this point, a Brueckner triplet dispersion energy

{W}_{3}^{D}

has not yet appeared. This

{W}_{3}^{D}

depends on a triplet excitation parameter ${\ensuremath{\kappa}}_{3}$, which is calculated using Jastrow correlation functions. We find that ${\ensuremath{\kappa}}_{3}$ is small when ${\ensuremath{\kappa}}_{2}$ is small (\ensuremath{\lesssim} 0.1), and large when ${\ensuremath{\kappa}}_{2}$ is large (\ensuremath{\gtrsim} 0.4). Since ${\ensuremath{\kappa}}_{2}\ensuremath{\approx}0.2$ in nuclear matter, there is hope that both Brueckner and Iwamoto-Yamada expansions converge to the same answer at fairly low orders.NUCLEAR STRUCTURE Fermion fluids, nuclear matter; compared Brueckner and IY expansions; calculated triplet excitation parameter.