A5027088079- Pulsars and Gravitational Waves Research
- Nuclear physics research studies
- Gamma-ray bursts and supernovae
- Quantum, superfluid, helium dynamics
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- High-pressure geophysics and materials
- Neutrino Physics Research
- Atomic and Subatomic Physics Research
- Geophysics and Gravity Measurements
- History and Developments in Astronomy
- Planetary Science and Exploration
- Astrophysical Phenomena and Observations
- Astro and Planetary Science
- Geophysics and Sensor Technology
- Stellar, planetary, and galactic studies
- Dark Matter and Cosmic Phenomena
- Historical Astronomy and Related Studies
- Ga2O3 and related materials
- Scientific Research and Discoveries
- Electron and X-Ray Spectroscopy Techniques
- Semiconductor materials and devices
Daegu University
2025
Osaka University
2025
Tohoku University
2009-2024
Campbell Collaboration
2023
Waseda University
2012-2022
Kyushu University
2019-2021
RIKEN Nishina Center
2016-2020
RIKEN
2014-2017
Abstract This review aims at providing an extensive discussion of modern constraints relevant for dense and hot strongly interacting matter. It includes theoretical first-principle results from lattice perturbative QCD, as well chiral effective field theory results. From the experimental side, it heavy-ion collision low-energy nuclear physics results, observations neutron stars their mergers. The validity different constraints, concerning specific conditions ranges applicability, is also provided.
Fully general-relativistic binary-neutron-star (BNS) merger simulations with quark-hadron crossover (QHC) equations of state (EOS) are studied for the first time. In contrast to EOS purely hadronic matter or a first-order phase transition (1PT), in region QHC show peak sound speed and thus stiffening. We study effects such stiffening postmerger gravitational (GW) signals. Through binary-mass range 2.5<M/M_{⊙}<2.75, characteristic differences due different appear frequency main GW spectrum...
We have constructed a nuclear equation of state (EOS) that includes full ensemble for use in core-collapse supernova simulations. It is based on the EOS uniform matter two authors derived recently, applying variational method to realistic two- and there-body forces. utilize an extended liquid drop model heavy nuclei quantum-theoretical mass evaluation light nuclei. In addition forces, inclusion in-medium effects makes new one most EOS's make comparisons with FYSS EOS, which same formulation...
We present a much improved equation of state for neutron star matter, QHC19, with smooth crossover from the hadronic regime at lower densities to quark higher densities. now use Togashi et al.~equation (Togashi:2017), generalization Akmal-Pandharipande-Ravenhall uniform nuclear in entire regime; consistently describes non-uniform as well and matter beta equilibrium without need an interpolation between pure symmetric matter. describe Nambu--Jona--Lasinio model, identifying tight constraints...
We investigate the effects of odd-state part bare $\Lambda \Lambda$ interactions on structure neutron stars (NSs) by constructing equations state (EOSs) for uniform nuclear matter containing $\Lambda$ and $\Sigma^-$ hyperons with use cluster variational method. The isoscalar Argonne v18 two-nucleon potential Urbana IX three-nucleon are employed as between nucleons, whereas, N$ even-state interactions, two-body central potentials that determined so to reproduce experimental data single-...
We perform an extensive study of the influence nuclear weak interactions on core-collapse supernovae (CCSNe), paying particular attention to consistency between abundances in equation state (EOS) and interactions. compute properties uniform matter based variational method. For inhomogeneous matter, we take a full ensemble nuclei into account with various finite-density thermal effects directly use interaction rates. To quantify impact consistent treatment CCSN dynamics, carry out spherically...
Using the numerical simulation data for two-dimensional core-collapse supernova, we examine protoneutron star (PNS) asteroseismology with relativistic Cowling approximation. As shown in previous study, e.g., [H. Sotani and T. Takiwaki, Mon. Not. R. Astron. Soc. 498, 3503 (2020).], gravitational wave signals appearing can be well identified gravity (fundamental) oscillation early (later) phase before (after) avoided crossing between fundamental oscillations. On other hand, time evolution of...
The significance of the chiral symmetry restoration is studied by considering role modification nucleon mass in nuclear medium at finite density and temperature. Using Korea-IBS-Daegu-SKKU functional theory, we can create models that have an identical matter equation state but different isoscalar isovector effective masses zero effect becomes transparent non-zero temperatures, it more important as temperature increases. examined thoroughly calculating dependence thermodynamic variables such...
We investigate systematically the quark-hadron mixed phase in dense stellar matter and its influence on compact star structures. The properties of quark hadronic are fixed based various model predictions. Beside adopting constant values, surface tension $\mathrm{\ensuremath{\Sigma}}$ for interface is estimated with multiple reflection expansion method equivparticle model. To fix structures pasta phases, a continuous dimensionality structure adopted as proposed by Ravenhall et al....
This review aims at providing an extensive discussion of modern constraints relevant for dense and hot strongly interacting matter. It includes theoretical first-principle results from lattice perturbative QCD, as well chiral effective field theory results. From the experimental side, it heavy-ion collision low-energy nuclear physics results, observations neutron stars their mergers. The validity different constraints, concerning specific conditions ranges applicability, is also provided.
We delineate the quark-hadron continuity by constructing QCD equations of state for neutron star dynamics, covering wide range charge chemical potential (${\ensuremath{\mu}}_{Q}$) and temperatures ($T$). Based on nuclear-2SC scenario, we match nuclear two-flavor color-superconducting (2SC) quark matter, where matching baryon density is ${n}_{B}\ensuremath{\simeq}1.5{n}_{0}$ (${n}_{0}\ensuremath{\simeq}0.16\text{ }\text{ }{\mathrm{fm}}^{\ensuremath{-}3}$: saturation density). The effective...
The existence of neutron stars with $2M_\odot$ requires the strong stiffness equation state (EoS) neutron-star matter. We introduce a multi-pomeron exchange potential (MPP) working universally among 3- and 4-baryons to stiffen EoS. Its strength is restricted by analyzing nucleus-nucleus scattering G-matrix folding model. EoSs are derived using Brueckner-Hartree-Fock (BHF) cluster variational method (CVM) nuclear interactions ESC AV18. mass-radius relations solving Tolmann-Oppenheimer-Volkoff...
A protoneutron star (PNS) is a newly formed compact object in core collapse supernova. In this paper, the neutrino emission from cooling process of PNS investigated using two types nuclear equation state (EOS). It found that signal mainly determined by high-density EOS. The luminosity and mean energy are higher time scale longer for softer Meanwhile, also affected low-density EOS because difference population heavy nuclei. Heavy nuclei have large scattering cross section with neutrinos owing...
Core-collapse simulations of massive stars are performed using the equation state (EOS) based on microscopic variational calculation with realistic nuclear forces. The progenitor models initial masses $15M_\odot$, $9.6M_\odot$, and $30M_\odot$ adopted as examples ordinary core-collapse supernova a shock stall, low-mass successful explosion, black hole formation, respectively. Moreover, neutrinos emitted from stellar collapse assessed. Then, EOS is confirmed to work well in all cases....
The equation of state (EOS) for hot asymmetric nuclear matter which is constructed with the variational method starting from Argonne v18 and Urbana IX forces applied to spherically symmetric core-collapse supernovae (SNe). We first investigate EOS isentropic beta-stable SN matter, find that more neutron-rich than Shen EOS. Using uniform supplemented by non-uniform at low densities, we perform general-relativistic simulations SNe without neutrino transfer, a presupernova model 15 solar mass....
We derive the empirical formulas for neutron star mass and gravitational redshift as a function of central density specific combination nuclear saturation parameters, which are applicable to stellar models constructed with up threefold density. Combining both formulas, one also estimates radius. In practice, we find that (radius) can be estimated within $\sim 10\%$ (a few percent) accuracy by comparing radius evaluated our those determined equation state. Since directly connect discuss...
The shear modulus of neutron star matter is one the important properties for determining torsional oscillations in stars. We take into account effects finite sizes spherical nuclei on and examine frequencies crustal oscillations. decreases owing to finite-size effect, which turn In particular, effect becomes more crucial with a larger azimuthal quantum number models weaker density dependence nuclear symmetry energy. practice, when identifies quasi-periodic from star, where magnetic...
We study the influence of hot and dense matter in core-collapse supernovae by adopting up-to-date nuclear equation state (EOS) based on microscopic many-body frameworks. explore effects EOS Dirac Brueckner Hartree-Fock theory through comparisons with those variational method. also examine differences composition nuclei nucleons using same method but employing two different treatments computations abundances. perform numerical simulations three EOSs. long-term evolution over 70 s...
Abstract We calculate new equations of state (EOSs) for astrophysical simulations in the framework extended nuclear statistical equilibrium, which we minimize free energy density full ensemble nuclei a hot and dense stellar environment. To evaluate bulk surface energies heavy uniformly distributed nucleons, use fitting formulae interaction single-nucleon potentials at zero temperature Dirac–Brückner Hartree–Fock (DBHF) theory, one modern approaches to describe homogeneous matter. find that...
Initial oxidation processes of the Si(110) surface and chemical bonding states silicon atoms in initial oxides have been investigated by using real-time synchrotron-radiation photoemission spectroscopy. Time evolutions Sin+ (n=1–4) components Si 2p spectrum indicates that Si3+ component always overwhelms Si4+ during up to one monolayer. This is sharp contrast Si(001) where Si4+&gt;Si3+ holds. The dominance related presence two types bonds on their possible different reactivity against...
We report on an equation of state (EOS) hot asymmetric nuclear matter constructed using the variational method and its application to hydrodynamic simulations core-collapse supernovae. This EOS is based AV18 two-body potential UIX three-body potential, energy per nucleon at zero temperature with cluster method. At finite temperatures, free energies are calculated extension devised by Schmidt Pandharipande. in good agreement that Fermi hypernetted chain calculations structure neutron stars...
We report the current status of our project to construct a new nuclear equation state (EOS), which may be used for supernova numerical simulations, based on cluster variational method starting from realistic Hamiltonian. also take into account higher-order correction energy three-body force (TBF). The EOSs with and without TBF at zero temperature are very close each other, when parameters readjusted so as reproduce empirical saturation data.
We calculated the energies of asymmetric nuclear matter at zero and finite temperatures with cluster variational method. At temperature, expectation value two-body Hamiltonian composed kinetic AV18 forces is Jastrow wave function in approximation. The obtained energy good agreement result Fermi Hypernetted Chain (FHNC) calculation by Akmal et al. caused UIX three-body treated somewhat phenomenologically so that total reproduces empirical saturation point. Furthermore, parameters included are...