Regulator artifacts in uniform matter for chiral interactions

Dyhdalo, A.; Furnstahl, R. J.; Hebeler, K.; Tews, Ingo

doi:10.1103/physrevc.94.034001

Cited by 50 publications

(80 citation statements)

References 65 publications

(114 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Local regulators for pion exchanges have been investigated in detail in Ref. [112] in both the NN and 3N sector. The fact that the contribution due to pion exchanges is weaker for local than for nonlocal regulator functions is easy to understand in the Hartree-Fock approximation.…”

Section: Weaker Pion Exchangesmentioning

confidence: 99%

Local Nucleon-Nucleon and Three-Nucleon Interactions Within Chiral Effective Field Theory

Piarulli¹,

Tews

2020

Front. Phys.

View full text Add to dashboard Cite

To obtain an understanding of the structure and reactions of nuclear systems from first principles has been a long-standing goal of nuclear physics. In this respect, few-and many-body systems provide a unique laboratory for studying nuclear interactions. During the past decades, the development of accurate representations of the nuclear force has undergone substantial progress. Particular emphasis has been devoted to chiral effective field theory (EFT), a low-energy effective representation of quantum chromodynamics (QCD). Within chiral EFT, many studies have been carried out dealing with the construction of both the nucleon-nucleon (NN ) and three-nucleon (3N ) interactions. The aim of the present article is to give a detailed overview of the chiral interaction models that are local in configuration space, and show recent results for nuclear systems obtained by employing these local chiral forces. Keywords: nuclear interactions, chiral effective field theory, local interactions, three-body forces, ab-initio calculations arXiv:2002.00032v1 [nucl-th] 31 Jan 2020 Piarulli et al. Local chiral interactionsIn fact, chiral symmetry is broken twofold. First, it is broken spontaneously, leading to the formation of Goldstone bosons, that can be identified with the pions. Second, chiral symmetry is also explicitly broken by the finite quark masses, which leads to the pion being pseudo-Goldstone bosons with finite but small mass. In contrast, isospin symmetry remains a good symmetry, because the ratio (m d − m u )/Λ QCD is very small, where m u 2.4 MeV and m d 4.8 MeV.These symmetries only allow certain operator structures for nuclear interactions. Galilean invariance, for instance, implies that nuclear interactions depend only on relative momenta between two nucleons, p = p i − p j , while symmetry under parity transformations implies that nuclear interactions cannot be Frontiers

show abstract

Section: Weaker Pion Exchangesmentioning

confidence: 99%

Local Nucleon-Nucleon and Three-Nucleon Interactions Within Chiral Effective Field Theory

Piarulli¹,

Tews

2020

Front. Phys.

View full text Add to dashboard Cite

show abstract

“…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

295

213

View full text Add to dashboard Cite

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.

show abstract

“…3, chiral interactions become less reliable with increasing density. This is especially true for the local interactions employed when obtaining the AFDMC band, because they suffer from sizable local regulator artifacts [38,51,52]. To estimate the sensitivity of these uncertainties, we also explore MBPT calculations with nonlocal chiral interactions [9], which do not suffer from these additional regulator artifacts.…”

mentioning

confidence: 99%

Spin-polarized Neutron Matter, the Maximum Mass of Neutron Stars, and GW170817

Tews

Schwenk

2020

ApJ

Self Cite

View full text Add to dashboard Cite

We investigate how a phase transition from neutron-star (NS) matter to spin-polarized neutron matter (SPM) affects the equation of state (EOS) and mass-radius relation of NS. While general extension schemes for the EOS allow for high energy densities and pressures inside NSs, we find that a phase transition to SPM excludes extreme regimes in these extensions. Hence, such a phase transition limits the maximum mass of NSs to lie below 2.6−2.9 M , depending on the microscopic nuclear forces used, while significantly larger masses of 3−4 M could be reached without these constraints. Remarkably, this lower maximum mass is in good agreement with recent constraints extracted from the NS merger GW170817 and its electromagnetic counterpart. Assuming the description in terms of SPM to be valid up to densities in the core of NSs, we find that stars with a large spin-polarized domain in their core are ruled out by the gravitational-wave observation GW170817.Motivation.-Neutron star (NS) observations, such as the recent detection of two merging NSs in the gravitational-wave (GW), gamma-ray, and electromagnetic (EM) spectra [1-4], designated as GW170817, GRB 170817A, and AT 2017gfo, respectively, provide crucial constraints on the equation of state (EOS) of dense strongly interacting matter. The EOS is a key quantity for astrophysics and sensitively depends on strong interactions. Hence, it connects astrophysical observations to laboratory experiments at rare isotope beam facilities for the most neutron-rich extremes at RIBF, Japan, and the future FRIB and FAIR facilities in the US and Germany, respectively. While there is a wealth of theoretical models for the EOS of NS matter (see for reviews), obtained from different theories for strong interactions and with various methods, for densities beyond nuclear saturation density n sat ≈ 0.16 fm −3 these models can only be confronted with a limited set of experimental data, e.g., from heavy-ion collisions [8].Neutron stars are the densest objects in the Universe and probe the EOS up to several times saturation density. Neutron-star observations are therefore an ideal source of additional information that complements experimental data and provides powerful constraints for the EOS at higher densities [14,15]. The structure of a NS is described by the mass-radius (M -R) relation, which is an important observational quantity and in a one-to-one correspondence with the EOS: The M -R relation follows from the EOS by solving the Tolman-Oppenheimer-Volkoff (TOV) equations [16,17]. Measuring the M -R relation, and therefore the EOS, observationally is however extremely difficult. On the one hand, NS masses can be determined very precisely for some NSs in binaries [18]. For example, the precise measurement of two two-solar-mass NSs [19-21] established a robust and

show abstract

Regulator artifacts in uniform matter for chiral interactions

Cited by 50 publications

References 65 publications

Local Nucleon-Nucleon and Three-Nucleon Interactions Within Chiral Effective Field Theory

Local Nucleon-Nucleon and Three-Nucleon Interactions Within Chiral Effective Field Theory

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

Spin-polarized Neutron Matter, the Maximum Mass of Neutron Stars, and GW170817

Contact Info

Product

Resources

About