Quantum Monte Carlo calculations of neutron matter with chiral three-body forces

Tews, Ingo; Gandolfi, Stefano; Gezerlis, Alexandros; Schwenk, A.

doi:10.1103/physrevc.93.024305

Cited by 178 publications

(235 citation statements)

References 42 publications

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“…Only one calculation violates the UG constraint within its uncertainty band: a QMC N 2 LO calculation using soft chiral forces (Lynn et al 2016). This is due to artifacts from local regulators, which lead to less repulsion from 3N forces (Dyhdalo et al 2016;Tews et al 2016), and is peculiar to that interaction.…”

Section: The Ug As a Lower Energy Limit To Pure Neutron Mattermentioning

confidence: 99%

Symmetry Parameter Constraints from a Lower Bound on Neutron-matter Energy

Tews¹,

Lattimer²,

Ohnishi³

et al. 2017

ApJ

289

213

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We propose the existence of a lower bound on the energy of pure neutron matter (PNM) on the basis of unitary-gas considerations. We discuss its justification from experimental studies of cold atoms as well as from theoretical studies of neutron matter. We demonstrate that this bound results in limits to the density-dependent symmetry energy, which is the difference between the energies of symmetric nuclear matter and PNM. In particular, this bound leads to a lower limit to the volume symmetry energy parameter S 0 . In addition, for assumed values of S 0 above this minimum, this bound implies both upper and lower limits to the symmetry energy slope parameter L, which describes the lowest-order density dependence of the symmetry energy. A lower bound on neutron-matter incompressibility is also obtained. These bounds are found to be consistent with both recent calculations of the energies of PNM and constraints from nuclear experiments. Our results are significant because several equations of state that are currently used in astrophysical simulations of supernovae and neutron star mergers, as well as in nuclear physics simulations of heavy-ion collisions, have symmetry energy parameters that violate these bounds. Furthermore, below the nuclear saturation density, the bound on neutron-matter energies leads to a lower limit to the density-dependent symmetry energy, which leads to upper limits to the nuclear surface symmetry parameter and the neutron-star crust-core boundary. We also obtain a lower limit to the neutron-skin thicknesses of neutronrich nuclei. Above the nuclear saturation density, the bound on neutron-matter energies also leads to an upper limit to the symmetry energy, with implications for neutron-star cooling via the direct Urca process.

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Section: The Ug As a Lower Energy Limit To Pure Neutron Mattermentioning

confidence: 99%

Symmetry Parameter Constraints from a Lower Bound on Neutron-matter Energy

Tews¹,

Lattimer²,

Ohnishi³

et al. 2017

ApJ

289

213

View full text Add to dashboard Cite

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“…At higher densities, effects of three-body forces and higher-order pion-exchange processes become increasingly important [104,105], and it is crucial that any realistic approach takes into account fluctuations and correlations generated by those mechanisms. In Section 2 the functional renormalization group has been described as a powerful method to study the effects of fluctuations in a consistent and fully non-perturbative way.…”

Section: Functional Renormalization Group and Nuclear Many-body Problemmentioning

confidence: 99%

Functional renormalization group studies of nuclear and neutron matter

Drews

Weise

2017

Progress in Particle and Nuclear Physics

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Functional renormalization group (FRG) methods applied to calculations of isospinsymmetric and asymmetric nuclear matter as well as neutron matter are reviewed. The approach is based on a chiral Lagrangian expressed in terms of nucleon and meson degrees of freedom as appropriate for the hadronic phase of QCD with spontaneously broken chiral symmetry. Fluctuations beyond mean-field approximation are treated solving Wetterich's FRG flow equations. Nuclear thermodynamics and the nuclear liquid-gas phase transition are investigated in detail, both in symmetric matter and as a function of the proton fraction in asymmetric matter. The equations of state at zero temperature of symmetric nuclear matter and pure neutron matter are found to be in good agreement with advanced ab-initio many-body computations. Contacts with perturbative many-body approaches (in-medium chiral perturbation theory) are discussed. As an interesting test case, the density dependence of the pion mass in the medium is investigated. The question of chiral symmetry restoration in nuclear and neutron matter is addressed. A stabilization of the phase with spontaneously broken chiral symmetry is found to persist up to high baryon densities once fluctuations beyond mean-field are included. Neutron star matter including beta equilibrium is discussed under the aspect of the constraints imposed by the existence of two-solar-mass neutron stars.

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“…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.…”

Section: Introductionmentioning

confidence: 99%

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

2016

Self Cite

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We calculate the properties of isospin-asymmetric nuclear matter based on chiral nucleon-nucleon (NN) and three-nucleon (3N) interactions. To this end, we develop an improved normal-ordering framework that allows to include general 3N interactions starting from a plane-wave partial-wavedecomposed form. We present results for the energy per particle for general isospin asymmetries based on a set of different Hamiltonians, study their saturation properties, the incompressibility, symmetry energy, and also provide an analytic parametrization for the energy per particle as a function of density and isospin asymmetry.

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Quantum Monte Carlo calculations of neutron matter with chiral three-body forces

Cited by 178 publications

References 42 publications

Symmetry Parameter Constraints from a Lower Bound on Neutron-matter Energy

Symmetry Parameter Constraints from a Lower Bound on Neutron-matter Energy

Functional renormalization group studies of nuclear and neutron matter

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

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