Local chiral effective field theory interactions and quantum Monte Carlo applications

Abstract

We present details of the derivation of local chiral effective field theory interactions to next-tonext-to-leading order, and show results for nucleon-nucleon phase shifts and deuteron properties for these potentials. We then perform systematic auxiliary-field diffusion Monte Carlo calculations for neutron matter based on the developed local chiral potentials at different orders. This includes studies of the effects of the spectral-function regularization and of the local regulators. For all orders, we compare the quantum Monte Carlo results with perturbative many-body calculations and find excellent agreement for low cutoffs.

Comparative study of three-nucleon force models in nuclear matter

“…Making the usual angular average of the Pauli operator and of the energy denominator [46,54], the Bethe-Goldstone equation (17) can be expanded in partial waves. In all the calculations performed in this work, we have considered partial wave contributions up to a total two-body angular momentum J max = 9.…”

“…The important role played by the three-nucleon forces (TNFs) has been widely pointed out both in finite nuclei and nuclear matter calculations (see, e.g., [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] and references therein). First indications for the inclusion of a TNF in the nuclear Hamiltonian arose from the discrepancy between the results of the 3 H binding energy using different nucleonnucleon (NN) potentials and its experimental value.…”

In-medium similarity renormalization group for closed and open-shell nuclei

“…This implies that a simple extension of Wick's theorem for non-orthogonal product states can be applied to express the operator kernel (B.15) in terms of the basic contractions [197], the so-called transition density matrix and transition pairing tensors: 19) κ kl (φ k ) = Φ| a l a k |Φ(φ p , φ n ) Φ|Φ(φ p , φ n ) . (B.20)…”

“…Instead, we start from nuclear interactions that describe low-energy QCD observables in the N N and 3N systems, like scattering data or binding energies. Nowadays, such interactions are derived in Chiral Effective Field Theory (EFT), which provides a constructive framework and organizational hierarchy for N N , 3N , and higher many-nucleon forces, as well as consistent electroweak operators (see, e.g., [14][15][16][17][18][19][20][21][22][23][24][25]). Since Chiral EFT is a lowmomentum expansion, high-momentum (short-range) physics is not explicitly resolved by the theory, but parametrized by the so-called low-energy constants (LECs).…”

Asymmetric nuclear matter based on chiral two- and three-nucleon interactions

“…In subsequent studies, symmetric matter and neutron matter were also investigated based on chiral EFT interactions within the self-consistent Green's function framework [9,10], using coupled-cluster theory [11,12], with in-medium chiral perturbation theory [13] and in many-body perturbation theory [14]. Furthermore, the development of novel local chiral NN forces opened the way to first Quantum Monte Carlo studies of neutron matter based on chiral EFT interactions [15][16][17][18]. The results of these studies also represent first nonperturbative validation of many-body perturbation theory for neutron matter.…”