Nuclear Theory·nucl-th

Tuesday·October 26, 2021

8 papers—1 primary·7 cross-listed

01
[Submitted on 25 Oct 2021]
Optimization of basis functions for the multi-configuration mixing using the Replica Exchange Monte-Carlo method and its application to $^{12}$ C
Takatoshi Ichikawa · Naoyuki Itagaki
To calculate excited states in quantum many-body systems, multi-configuration mixing has often been employed. However, it has been still unclear how to choose important Slater determinants from a huge model space. We propose a novel efficient method as the Replica Exchange Monte-Carlo (RXMC) method to sample important Slater determinants and optimize and analyze the obtained results. As an application, we apply it to the ground and excited states of $^{12}$ C based on the Bloch-Brink $α$ cluster model and show the detailed structure of the obtained states. The RXMC method enables us to efficiently sample Slater determinants following the Boltzmann distribution on the multi-dimensional potential energy surface (PES) under a given model space. To analyze the obtained excited states, we embed sampled basis functions onto the PES calculated with the $β$ - $γ$ constraint method and discuss the main component in the state. The RXMC method can efficiently perform the samplings with a temperature parameter of $T_{L} = 2.5$ MeV in $^{12}$ C. We obtain the gas-like state with a wide density distribution in the tail part in the second $0^{+}$ state. We also obtain the linear-chain-like states with the bending and stretching vibrational modes in the third and fourth $0^{+}$ states, respectively. In the fifth $0^{+}$ state, the main component of the basis functions contains expanded equilateral triangle configurations. The second $0^{+}$ gas-like state emerges at the local minimum in the PES, which is the beginning of the valley structure connected to the linear-chain breakup channel. The third and fourth linear-chain-like states emerge in this valley structure. We conclude that the RXMC method is a powerful method to calculate the excited states of nuclei, which would be applied to much complicated nuclear fission dynamics in heavier nuclei.
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2110.12869 [pdf]
PRC(2022)·10 citations
02
[Submitted on 22 Oct 2021] (cross-list from astro-ph.HE)
Jet Launching from Merging Magnetized Binary Neutron Stars with Realistic Equations of State
Milton Ruiz · Antonios Tsokaros · Stuart L. Shapiro
We perform general relativistic, magnetohydrodynamic (GRMHD) simulations of binary neutron stars in quasi-circular orbit that merge and undergo delayed or prompt collapse to a black hole (BH). The stars are irrotational and modeled using an SLy or an H4 nuclear equation of state. To assess the impact of the initial magnetic field configuration on jet launching, we endow the stars with a purely poloidal magnetic field that is initially unimportant dynamically and is either confined to the stellar interior or extends from the interior into the exterior as in typical pulsars. Consistent with our previous results, we find that only the BH + disk remnants originating from binaries that form hypermassive neutron stars (HMNSs) and undergo delayed collapse can drive magnetically-powered jets. We find that the closer the total mass of the binary is to the threshold value for prompt collapse, the shorter is the time delay between the gravitational wave peak amplitude and jet launching. This time delay also strongly depends on the initial magnetic field configuration. We also find that seed magnetic fields confined to the stellar interior can launch a jet over $\sim 25 ms$ later than those with pulsar-like magnetic fields. The lifetime of the jet [ $Δ t ≲ 150 ms$ ] and its outgoing Poynting luminosity [ $L_{EM} \sim 1 0^{52 \pm 1} erg/s$ ] are consistent with typical short gamma-ray burst central engine lifetimes, as well as with the Blandford--Znajek mechanism for launching jets and their associated Poynting luminosities. Our numerical results also suggest that the dynamical ejection of matter can be enhanced by the magnetic field. Therefore, GRMHD studies are required to fully understand kilonova signals from GW170818-like events.
Comments:
21 pages, 12 figures. Matches published version
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
2110.11968 [pdf]
PRD(2021)·32 citations
03
[Submitted on 22 Oct 2021] (cross-list from hep-ph)
QCD Sum Rules at High Temperature
Thors Hans Hansson🇸🇪 · Ismail Zahed🇺🇸
We generalize the sum rule approach to investigate the nonperturbative structure of QCD at high temperature. Salient features of the QCD phase above $T_{c}$ are discussed, and included in the form of power corrections or condensate insertions, in an operator product expansion of gauge invariant correlators. It is shown that for a plausible choice of condensates, QCD at high temperature exhibits color singlet excitations in the vector channels, as opposed to merely screened quarks and gluons.
Comments:
This paper was posted on the SLAC server on June 5, 1990
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2110.12086 [pdf]
1 citation
04
[Submitted on 23 Oct 2021] (cross-list from hep-lat)
Thermal QCD with external imaginary electric fields on the lattice
Gergely Endrodi🇩🇪 · Gergely Marko🇩🇪
We study QCD at finite temperature in the presence of imaginary electric fields. In particular, we determine the electric susceptibility, the leading coefficient in the expansion of the QCD pressure in the imaginary field. Unlike for magnetic fields, at nonzero temperature this coefficient requires a non-trivial separation of genuine electric field-related effects and spurious effects related to the chemical potential, which becomes an unphysical gauge parameter in this setting. Our results are based on lattice simulations with stout improved dynamical staggered quarks at physical quark masses.
Comments:
8 pages, 6 figures, contribution to the 38th International Symposium on Lattice Field Theory (LATTICE21)
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2110.12189 [pdf]
PoS(2022)·8 citations
05
[Submitted on 23 Oct 2021] (cross-list from hep-ph)
A simple model to include initial-state and hot-medium effects in the computation of quarkonium nuclear modification factor
Miguel Ángel Escobedo🇪🇸 · Elena G. Ferreiro🇪🇸
Quarkonium suppression is one of the more useful observables to obtain information about the hot medium created in ultrarelativistic heavy-ion collisions. In this manuscript, we discuss a simple way to implement both the initial-state effects and the hot-medium evolution, and to compute the quarkonium nuclear modification factor if the survival probability for a bound state at a given energy density is known. Based on the Glauber model, the temperature of the evolving medium and the centrality dependence of the nuclear modification factor will be analysed.
Comments:
22 pages, 4 figure. Updated to match published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2110.12295 [pdf]
PRD(2022)·6 citations
06
[Submitted on 25 Oct 2021] (cross-list from hep-ph)
Impacts of (inverse) magnetic catalysis on screening masses of neutral pions and sigma mesons in hot and magnetized quark matter
Bing-kai Sheng🇨🇳 · Xinyang Wang🇨🇳 · Lang Yu🇨🇳
We investigate the screening masses of neutral pions and sigma mesons in hot and magnetized quark matter in the framework of a two-flavor lattice-improved Nambu-Jona-Lasinio (NJL) model with a magnetic field dependent coupling constant, which is determined by utilizing the results from lattice QCD simulations. Since such model can well reproduce inverse magnetic catalysis (IMC), by comparing with the standard NJL model, we systemically analyze the impacts of IMC on the temperature and magnetic field dependences of the longitudinal and transverse screening masses of the chiral partners, i.e. {\pi}^0 and {\sigma} mesons, as well as the screening mass differences between them. Particularly, it is found that the eB dependences of two alternative (pseudo)critical temperatures for the chiral transition defined by {\sigma}-{\pi}^0 meson screening mass differences are consistent with that defined by the quark condensate.
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2110.12811 [pdf]
PRD(2022)·25 citations
07
[Submitted on 25 Oct 2021] (cross-list from hep-th)
Correlations of mixed systems in confining backgrounds
Mahdis Ghodrati🇰🇷
We show that the entanglement of purification and the critical distance between the two mixed systems is a powerful measure in probing the phase structures of QCD and confining backgrounds, as it can distinguish the scale of chiral symmetry breaking versus the scale of confinement/deconfinement phase transitions. For two symmetric strips with equal and finite width and infinite length, and in the background of several confining geometries, we numerically calculate the critical distance between them where the mutual information vanishes and show that this quantity can probe the very rich phase structures of these backgrounds. The geometries that we study here are AdS-soliton, Witten Sakai Sugimoto and deformed Sakai-Sugimoto, Witten-QCD, Klebanov-Strassler, Klebanov-Tseytlin, Klebanov-Witten, Maldacena-Nunez, Nunez-Legramandi metric, and Domain-Wall QCD model. For each background we also present the relation for the entanglement of purification. Finally, we show that the Crofton forms of these geometries also behave in a universal form where a "well" is being observed around the IR wall, and therefore for all confining backgrounds, the Crofton form would also be capable of distinguishing the confining versus conformal backgrounds as it is also a tool in the reconstruction of various bulk geometries.
Comments:
52 pages, 48 figures, v3: Figures have been improved
Subjects:
High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2110.12970 [pdf]
EPJC(2022)·13 citations
08
[Submitted on 25 Oct 2021] (cross-list from astro-ph.HE)
Constraining exotic compact stars composed of bosonic and fermionic dark matter with gravitational wave events
Stephan Wystub🇩🇪 · Yannick Dengler🇩🇪 · Jan-Erik Christian🇩🇪 · Jürgen Schaffner-Bielich🇩🇪
We investigate neutron star-black hole (NS-BH) merger candidates as a test for compact exotic objects. Using the events GW190814, GW200105 and GW200115 measured by the LIGO-Virgo collabration, which represent a broad profile of the masses in the NS mass spectrum, we demonstrate the constraining power for the parameter spaces of compact stars consisting of dark matter for future measurements. We consider three possible cases of dark matter stars: self-interacting, purely bosonic or fermionic dark matter stars, stars consisting of a mixture of interacting bosonic and fermionic matter, as well as the limiting case of selfbound stars. We find that the scale of those hypothetical objects are dominated by the one of the strong interaction. The presence of fermionic dark matter requires a dark matter particle of the GeV mass scale, while the bosonic dark matter particle mass can be arbitrarily large or small. In the limiting case of a selfbound linear equation of state, we find that the vacuum energy of those configurations has to be similar to the one of QCD.
Comments:
6 pages, 4 figures, 3 tables. In accordance with the CRC-TR 211 Data Management Policy, the research data for section 1 and 4 of this study are available as ancilliary files, while the research data of section 3 is made available under http://cloud.itp.uni-frankfurt.de/s/QYARcPkmqKW5ain
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2110.12972 [pdf]
MNRAS(2023)·17 citations

Affiliations

first authorsco-authorsvia INSPIRE