Nuclear Theory·nucl-th

Monday·August 15, 2016

5 papers—5 primary·0 cross-listed

01
[Submitted on 11 Aug 2016]
Ab initio and phenomenological studies of the static response of neutron matter
Mateusz Buraczynski · Alexandros Gezerlis
We investigate the problem of periodically modulated strongly interacting neutron matter. We carry out ab initio non-perturbative auxiliary-field diffusion Monte Carlo calculations using an external sinusoidal potential in addition to phenomenological two- and three-nucleon interactions. Several choices for the wave function ansatz are explored and special care is taken to extrapolate finite-sized results to the thermodynamic limit. We perform calculations at various densities as well as at different strengths and periodicities of the one-body potential. Our microscopic results are then used to constrain the isovector term from energy-density functional theories of nuclei at many different densities, while making sure to separate isovector contributions from bulk properties. Lastly, we use our results to extract the static density-density linear response function of neutron matter at different densities. Our findings provide insights into inhomogeneous neutron matter and are related to the physics of neutron star crusts and neutron-rich nuclei.
Comments:
11 pages, 15 figures; 1 figure added; v2 corresponds to published version
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Quantum Gases (cond-mat.quant-gas); Strongly Correlated Electrons (cond-mat.str-el)
arXiv:
1608.03598 [pdf]
PRC(2017)·28 citations
02
[Submitted on 12 Aug 2016]
Tetrahedral shape and surface density wave of $^{16}$ O caused by $α$ -cluster correlations
Yoshiko Kanada-En'yo · Yoshimasa Hidaka
$α$ -cluster correlations in the $0_{1}^{+}$ and $3_{1}^{-}$ states of $^{12}$ C and $^{16}$ O are studied using the method of antisymmetrized molecular dynamics, with which nuclear structures are described from nucleon degrees of freedom without assuming existence of clusters. The intrinsic states of $^{12}$ C and $^{16}$ O have triangle and tetrahedral shapes, respectively, because of the $α$ -cluster correlations. These shapes can be understood as spontaneous symmetry breaking of rotational invariance, and the resultant surface density oscillation is associated with density wave (DW) caused by the instability of Fermi surface with respect to particle-hole correlations with the wave number $λ = 3$ . $^{16}$ O( $0_{1}^{+}$ ) and $^{16}$ O( $3_{1}^{-}$ ) are regarded as a set of parity partners constructed from the rigid tetrahedral intrinsic state, whereas $^{12}$ C( $0_{1}^{+}$ ) and $^{12}$ C( $3_{1}^{-}$ ) are not good parity partners as they have triangle intrinsic states of different sizes with significant shape fluctuation because of softness of the $3 α$ structure. $E 3$ transition strengths from the $3_{1}^{-}$ to $0_{1}^{+}$ states in $^{12}$ C and $^{16}$ O are also discussed.
Comments:
13 pages, 8 figures. arXiv admin note: text overlap with arXiv:1208.3275
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1608.03642 [pdf]
3 citations
03
[Submitted on 12 Aug 2016]
Energy dependence of resonance production in relativistic heavy ion collisions
Feng-lan Shao🇨🇳 · Jun Song🇨🇳 · Rui-qin Wang🇨🇳 · Mao-sheng Zhang🇨🇳
The production of hadronic resonances $K^{*} (892)$ , $ϕ (1020)$ , $Σ^{*} (1385)$ , and $Ξ^{*} (1530)$ in central AA collisions at $s_{N N} =$ 17.3, 200, and 2760 GeV are systematically studied. The direct production of these resonances at system hadronization are described by the quark combination model and the effects of hadron multiple-scattering stage are dealt with by a ultra-relativistic quantum molecular dynamics model (UrQMD). We study the contribution of these two production sources to final observation and compare the final spectra with the available experimental data. The $p_{T}$ spectra of $K^{*} (892)$ calculated directly by quark combination model are explicitly higher than the data at low $p_{T} ≲ 1.5$ GeV and taking into account the modification of rescattering effects the resulting final spectra well agree with the data at all three collision energies. The rescattering effect on $ϕ (1020)$ production is weak and including it can slightly improve our description at low $p_{T}$ on the basis of overall agreement with the data. We also predict the $p_{T}$ spectra of $Σ^{*} (1385)$ and $Ξ^{*} (1530)$ to be tested by the future experimental data.
Comments:
5 pages, 6figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1608.03675 [pdf]
CPC(2017)·0 citations
04
[Submitted on 12 Aug 2016]
Coordinate-Space Solver for Superfluid Many-Fermion Systems with Shifted Conjugate Orthogonal Conjugate Gradient Method
Shi Jin · Aurel Bulgac · Kenneth Roche · Gabriel Wlazłowski
Self-consistent approaches to superfluid many-fermion systems in 3-dimensions (and subsequent time-dependent approaches) require a large number of diagonalizations of very large dimension hermitian matrices, which results in enormous computational costs. We present an approach based on the shifted conjugate-orthogonal conjugate-gradient (COCG) method for the evaluation of the Green's function, from which we subsequently extract various densities (particle number, spin, current, kinetic energy, etc.) of a nuclear system needed in self-consistent approaches. The approach eschews the construction of the quasiparticle wavefunctions and their corresponding quasiparticle energies, which are never explicitly needed in any density functional approaches. As benchmarks we present calculations for nuclei with axial symmetry, including the ground state of spherical (magic or semi-magic) and axially deformed nuclei, the saddle-point in the $^{240}$ Pu constrained fission path, and a vortex in the neutron star crust.
Comments:
19 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th); Strongly Correlated Electrons (cond-mat.str-el)
arXiv:
1608.03711 [pdf]
PRC(2017)·39 citations
05
[Submitted on 12 Aug 2016]
Conserved charge fluctuations are not conserved during the hadronic phase
J. Steinheimer🇩🇪 · V. Vovchenko🇩🇪 · J. Aichelin🇩🇪 · M. Bleicher🇩🇪 · H. Stöcker🇩🇪
We study the correlation between the distributions of the net-charge, net-kaon, net-baryon and net-proton number at hadronization and after the final hadronic decoupling by simulating ultra relativistic heavy ion collisions with the hybrid version of the ultrarelativistic quantum molecular dynamics (UrQMD) model. We find that due to the hadronic rescattering these distributions are not strongly correlated. The calculated change of the correlation, during the hadronic expansion stage, does not support the recent paradigm, namely that the measured final moments of the experimentally observed distributions do give directly the values of those distributions at earlier times, when the system had been closer to the QCD crossover.
Comments:
7 pages, 5 figures, version accepted by PLB
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1608.03737 [pdf]
PLB(2018)·31 citations

Affiliations

first authorsco-authorsvia INSPIRE

Ab initio and phenomenological studies of the static response of neutron matter

Tetrahedral shape and surface density wave of 16O caused by α-cluster correlations

Energy dependence of resonance production in relativistic heavy ion collisions

Coordinate-Space Solver for Superfluid Many-Fermion Systems with Shifted Conjugate Orthogonal Conjugate Gradient Method

Conserved charge fluctuations are not conserved during the hadronic phase

Affiliations

Tetrahedral shape and surface density wave of $^{16}$ O caused by $α$ -cluster correlations