Further explorations of Skyrme–Hartree–Fock–Bogoliubov mass formulas. IV: Neutron-matter constraint

Goriely, Stéphane; Samyn, M.; Pearson, J. M.; Onsi, M.

doi:10.1016/j.nuclphysa.2005.01.009

Cited by 117 publications

(130 citation statements)

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“…The recent Skxs15, Skxs20, and Skxs25 Skyrme interactions [54] represent a reasonable variation of neutron-skin thickness in 208 Pb [52], with T = 0.15, 0.20, and 0.25 fm, respectively, and all have K = 200 MeV. We also compare to results with the widely used Sly4 interaction [55] (K = 230 MeV and T = 0.16 fm) and with the Bsk9 interaction [56] obtained from a recent global fit to binding energies together with the Friedman-Pandharipande prediction for P n (K = 230 MeV and T = 0.16 fm). The variation of the R s values is dominated by the different single-particle radii obtained from these Skyrme interactions that affects the single-particle cross sections as shown in Fig.…”

Section: Discussionmentioning

confidence: 90%

Reduction of spectroscopic strength: Weakly-bound and strongly-bound single-particle states studied using one-nucleon knockout reactions

et al. 2008

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Both one-proton and one-neutron knockout reactions were performed with fast beams of two asymmetric, neutron-deficient rare isotopes produced by projectile fragmentation. The reactions are used to probe the nucleon spectroscopic strengths at both the weakly and strongly bound nucleon Fermi surfaces. The one-proton knockout reactions 9 Be( 28 S, 27 P)X and 9 Be( 24 Si, 23 Al)X probe the weakly bound valence proton states and the one-neutron knockout reactions and 9 Be( 28 S, 27 S)X and 9 Be( 24 Si, 23 Si)X the strongly bound neutron states in the two systems. The spectroscopic strengths are extracted from the measured cross sections by comparisons with an eikonal reaction theory. The reduction of the experimentally deduced spectroscopic strengths, relative to the predictions of shell-model calculations, is of order 0.8-0.9 in the removal of weakly bound protons and 0.3-0.4 in the knockout of the strongly bound neutrons. These results support previous studies at the extremes of nuclear binding and provide further evidence that in asymmetric nuclear systems the nucleons of the deficient species, at the more-bound Fermi surface are more strongly correlated than those of the more weakly bound excess species.

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Section: Discussionmentioning

confidence: 90%

Reduction of spectroscopic strength: Weakly-bound and strongly-bound single-particle states studied using one-nucleon knockout reactions

et al. 2008

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“…The polaron energy follows from the energy density (3) by E pol = (∂E/∂ρ ↓ ) ρ ↓ =0 . Figure 3 shows the predic-tions for E pol of various state-of-the-art nuclear density functionals: SIII [49], SGII [50], SkM * [51], SLy4 and SLy5 [12], SkO and SkO [52], BSk9 [53], SAMi [54], as well as the Gogny D1N functional [13]. All functionals predict an attractive polaron energy, but E pol varies greatly among the different functionals and is generally underestimated.…”

Section: This Is Equivalent To the Dyson Equationmentioning

confidence: 99%

Neutron polaron as a constraint on nuclear density functionals

et al. 2014

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We study the energy of an impurity (polaron) that interacts strongly in a sea of fermions when the effective range of the impurity-fermion interaction becomes important, thereby mapping the Fermi polaron of condensed matter physics and ultracold atoms to strongly interacting neutrons. We present Quantum Monte Carlo results for this neutron polaron, and compare these with effective field theory calculations that also include contributions beyond the effective range. We show that stateof-the-art nuclear density functionals vary substantially and generally underestimate the neutron polaron energy. Our results thus provide constraints for adjusting the time-odd components of nuclear density functionals to better characterize polarized systems. Energy-density functionals are the only method available to study heavy nuclei and to globally describe the chart of nuclides [1,2]. Due to the need for a precise description of low-energy observables, parameters of these functionals are generally fit to properties of nuclei, including masses and radii. This empirical construction can therefore also benefit from additional input to constrain their properties in exotic, i.e., neutron-rich or spin-polarized systems. Examples of such pseudo-data include calculations of neutron matter [3-9] and neutron drops [10]. This approach has been successfully used to shape new functionals (see, e.g., Refs. [11-16]). In this work, we study the neutron polaron and use its energy as a constraint on nuclear density functionals.The polaron was first introduced in condensed matter physics, and has recently been investigated in strongly interacting ultracold Fermi gases [17] -a system that has many similarities with the physics of low-density neutron matter (see, e.g., Refs. [3,4]). The Fermi polaron is an impurity interacting in a Fermi sea, realized in ultracold atoms and neutron matter as a spin-down fermion in a sea of N ↑ spin-up fermions. The polaron energy E pol = E N ↑ +1 − E N ↑ is defined as the energy difference between the system with the polaron added and the N ↑ (noninteracting) Fermi system. In the thermodynamic limit, this is equivalent to the spin-down chemical potential in the limit of high polarization, and therefore constrains the phase diagram of strongly interacting Fermi systems as a function of spin imbalance [18][19][20][21][22].For attractive interactions, E pol < 0 measures the polaron binding energy in the Fermi sea. In the unitary limit, where the S-wave scattering length |a| → ∞, the polaron energy is universal at low densities and scales as E pol = ηE F where E F = k 2 F /2m is the Fermi energy (with Fermi momentum k F ) and η < 0 is a universal number [18]. Neutrons, whose scattering length is large (a = −18.5 fm), have low-density properties close to the unitary limit. At unitarity, the polaron energy admits a variational bound that sums one-particle-one-hole excitations, η ≤ −0.6066 [18], which is remarkably close to a full manybody treatment [23], η = −0.6158, and agrees with Quantum Monte Carlo (QMC) calculation...

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“…Today, there exists a large variety of Skyrme parameter sets [57]. For our work we chose two representative approaches for Skyrme models, BSk8 and SLy4 [58,59], which are applied in astrophysical and nuclear physics studies. Both models are fitted to reproduce properties of neutron rich nuclei and nuclear matter at saturation density.…”

Section: Maximum Neutron Star Massesmentioning

confidence: 99%

“…For a RMF model with n 0 = 0.17 fm −3 and K 0 = 220 MeV, we arrive at m * /m = (0.53 − 0.65) for n ∼ (2 − 3) n 0 while for K 0 = 250 MeV we obtain m * /m = (0.54 − 0.67) for the same density range. Other schemes, such as BSk8 [58], SLy4 [59] or NL3 [66], produce nucleon potentials which are more repulsive than the Skyrme benchmark in the density region of interest. Therefore, we find that while the BSk8, SLy4, and NL3 parametrizations are fitted to nuclear matter at saturation density they are not applicable for higher values of n ∼ (2 − 3)n 0 .…”

Section: Maximum Neutron Star Massesmentioning

confidence: 99%

Soft nuclear equation-of-state from heavy-ion data and implications for compact stars

Sagert

Tolós

Chatterjee³

et al. 2012

Phys. Rev. C

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Measurements of kaon production at subthreshold energies in heavy-ion collisions point to a soft nuclear equation-of-state for densities up to 2-3 times nuclear matter saturation density. We apply these results to study the implications on compact star properties, especially in the context of the recent measurement of the two solar mass pulsar PSR J1614-2230. The implications are twofold: Firstly, the heavy-ion results constrain nuclear matter at densities relevant to light neutron stars. Hence, a radius measurement could provide information about the density dependence of the symmetry energy which is a crucial quantity in nuclear physics. Secondly, the information on the nucleon potential obtained from the analysis of the heavy-ion data can be combined with restrictions from causality on the nuclear equation-of-state. From this we can derive a limit for the highest allowed compact star mass of three solar masses.

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Further explorations of Skyrme–Hartree–Fock–Bogoliubov mass formulas. IV: Neutron-matter constraint

Cited by 117 publications

References 50 publications

Reduction of spectroscopic strength: Weakly-bound and strongly-bound single-particle states studied using one-nucleon knockout reactions

Reduction of spectroscopic strength: Weakly-bound and strongly-bound single-particle states studied using one-nucleon knockout reactions

Neutron polaron as a constraint on nuclear density functionals

Soft nuclear equation-of-state from heavy-ion data and implications for compact stars

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