While hybrid approaches of relativistic hydrodynamics+transport have been well established for the dynamical description of heavy-ion collisions at high beam energies, moving to lower beam energies is challenging. In this work, we propose dynamic initial conditions for the viscous hydrodynamic evolution in heavy-ion collisions at low to intermediate beam energies. They are comprised of core hadrons based on the local energy density during the pre-equilibrium hadronic evolution. The SMASH-vHLLE hybrid approach is then applied to lower beam energies, achieving good agreement with measured bulk observables between $\sqrt{s_\mathrm{NN}} = 3$ and $9.1\ \mathrm{GeV}$, thus providing guidance for measurements in STAR-BES and CBM at FAIR. This framework has the advantage that the equation of state of dense QCD matter is a direct input to the calculation, so the current results can be regarded as a baseline with respect to future studies of the phase transition.

Black hole - neutron star (BHNS) mergers are a promising target of current gravitational-wave (GW) and electromagnetic (EM) searches, being the putative origin of ultra-relativistic jets, gamma-ray emission, and r-process nucleosynthesis. However, the possibility of any EM emission accompanying a GW detection crucially depends on the amount of baryonic mass left after the coalescence, i.e. whether the neutron star (NS) undergoes a `tidal disruption' or `plunges' into the black hole (BH) while remaining essentially intact. As the first of a series of two papers, we here report the most systematic investigation to date of quasi-equilibrium sequences of initial data across a range of stellar compactnesses $\mathcal{C}$, mass ratios $q$, BH spins $\chi_{_{\rm BH}}$, and equations of state satisfying all present observational constraints. Using an improved version of the elliptic initial-data solver FUKA, we have computed more than$1000$individual configurations and estimated the onset of mass-shedding or the crossing of the innermost stable circular orbit in terms of the corresponding characteristic orbital angular velocities$\Omega_{_{\rm MS}}$and$\Omega_{_{\rm ISCO}}$as a function of$\mathcal{C}, q$, and$\chi_{_{\rm BH}}$. To the best of our knowledge, this is the first time that the dependence of these frequencies on the BH spin is investigated. In turn, by setting$\Omega_{_{\rm MS}} = \Omega_{_{\rm ISCO}}$it is possible to determine the separatrix between the `tidal disruption' or `plunge' scenarios as a function of the fundamental parameters of these systems, namely,$q, \mathcal{C}$, and$\chi_{_{\rm BH}}$. Finally, we present a novel analysis of quantities related to the tidal forces in the initial data and discuss their dependence on spin and separation.

Modern hydrodynamic simulations of core-collapse supernovae and neutron-star mergers require knowledge not only of the equilibrium properties of strongly interacting matter, but also of the system's response to perturbations, encoded in various transport coefficients. Using perturbative and holographic tools, we derive here an improved weak-coupling and a new strong-coupling result for the most important transport coefficient of unpaired quark matter, its bulk viscosity. These results are combined in a simple analytic pocket formula for the quantity that is rooted in perturbative Quantum Chromodynamics at high densities but takes into account nonperturbative holographic input at neutron-star densities, where the system is strongly coupled. This expression can be used in the modeling of unpaired quark matter at astrophysically relevant temperatures and densities.

The density-constrained time-dependent Hartree-Fock (DC-TDHF) theory is a fully microscopic approach for calculating heavy-ion interaction potentials and fusion cross sections below and above the fusion barrier. We discuss recent applications of DC-TDHF method to fusion of light and heavy neutron-rich systems.

The KADoNiS-$p$ project is an online database for cross sections relevant to the $p$-process. All existing experimental data was collected and reviewed. With this contribution a user-friendly database using the KADoNiS (Karlsruhe Astrophysical Database of Nucleosynthesis in Stars) framework is launched, including all available experimental data from (p,$\gamma$), (p,n), (p,$\alpha$), ($\alpha$,$\gamma$), ($\alpha$,n) and ($\alpha$,p) reactions in or close to the respective Gamow window with cut-off date of August 2012 (this http URL).

A significant interest has emerged recently in assessing whether collimated and ultra-relativistic outflows can be produced by a long-lived remnant from a binary neutron-star (BNS) merger, with different approaches leading to different outcomes. To clarify some of the aspect of this process, we report the results of long-term (\ie $\sim~110\,{\rm ms}$) state-of-the-art general-relativistic magnetohydrodynamics simulations of the inspiral and merger of a BNS system of magnetized stars. We find that after $\sim~50\,{\rm ms}$ from the merger, an $\alpha$-$\Omega$~dynamo driven by the magnetorotational instability (MRI) sets-in in the densest regions of the disk and leads to the breakout of the magnetic-field lines from the accretion disk around the remnant. The breakout, which can be associated with the violation of the Parker-stability criterion, is responsible for the generation of a collimated, magnetically-driven outflow with only mildly relativistic velocities that is responsible for a violent eruption of electromagnetic energy. We provide evidence that this outflow is partly collimated via a Blandford-Payne mechanism driven by the open field lines anchored in the inner disk regions. Finally, by including or not the radiative transport via neutrinos, we determine the role they play in the launching of the collimated wind. In this way, we conclude that the mechanism of magnetic-field breakout we observe is robust and takes place even without neutrinos. Contrary to previous expectations, the inclusion of neutrinos absorption and emission leads to a smaller baryon pollution in polar regions, and hence accelerates the occurrence of the breakout, yielding a larger electromagnetic luminosity. Given the mildly relativistic nature of these disk-driven breakout outflows, it is difficult to consider them responsible for the jet phenomenology observed in short gamma-ray bursts.

We present a lattice QCD calculation of the up, down, strange and charm quark masses performed using the gauge configurations produced by the European Twisted Mass Collaboration with Nf = 2 + 1 + 1 dynamical quarks, which include in the sea, besides two light mass degenerate quarks, also the strange and charm quarks with masses close to their physical values. The simulations are based on a unitary setup for the two light quarks and on a mixed action approach for the strange and charm quarks. The analysis uses data at three values of the lattice spacing and pion masses in the range 210 - 450 MeV, allowing for accurate continuum limit and controlled chiral extrapolation. The quark mass renormalization is carried out non-perturbatively using the RI-MOM method. The results for the quark masses converted to the bar{MS} scheme are: mud(2 GeV) = 3.70(17) MeV, ms(2 GeV) = 99.6(4.3) MeV and mc(mc) = 1.348(46) GeV. We obtain also the quark mass ratios ms/mud = 26.66(32) and mc/ms = 11.62(16). By studying the mass splitting between the neutral and charged kaons and using available lattice results for the electromagnetic contributions, we evaluate mu/md = 0.470(56), leading to mu = 2.36(24) MeV and md = 5.03(26) MeV.

Gravitational Waves (GWs) from coalescing binaries carry crucial information about their component sources, like mass, spin and tidal effects. This implies that the analysis of GW signals from binary neutron star mergers can offer unique opportunities to extract information about the tidal properties of NSs, thereby adding constraints to the NS equation of state. In this work, we use Deep Learning (DL) techniques to overcome the computational challenges confronted in conventional methods of matched-filtering and Bayesian analyses for signal-detection and parameter-estimation. We devise a DL approach to classify GW signals from binary black hole and binary neutron star mergers. We further employ DL to analyze simulated GWs from binary neutron star merger events for parameter estimation, in particular, the regression of mass and tidal deformability of the component objects. The results presented in this work demonstrate the promising potential of DL techniques in GW analysis, paving the way for further advancement in this rapidly evolving field. The proposed approach is an efficient alternative to explore the wealth of information contained within GW signals of binary neutron star mergers, which can further help constrain the NS EoS.

The blow-up lemma states that a system of super-regular pairs contains all bounded degree spanning graphs as subgraphs that embed into a corresponding system of complete pairs. This lemma has far-reaching applications in extremal combinatorics. We prove sparse analogues of the blow-up lemma for subgraphs of random and of pseudorandom graphs. Our main results are the following three sparse versions of the blow-up lemma: one for embedding spanning graphs with maximum degree $\Delta$ in subgraphs of $G(n,p)$ with $p=C(\log n/n)^{1/\Delta}$; one for embedding spanning graphs with maximum degree $\Delta$ and degeneracy $D$ in subgraphs of $G(n,p)$ with $p=C_\Delta\big(\log n/n\big)^{1/(2D+1)}$; and one for embedding spanning graphs with maximum degree $\Delta$ in $(p,cp^{\max(4,(3\Delta+1)/2)}n)$-bijumbled graphs. We also consider various applications of these lemmas.

This paper is an extended abstract of an analysis of term rewriting where the terms in the rewrite rules as well as the term to be rewritten are compressed by a singleton tree grammar (STG). This form of compression is more general than node sharing or representing terms as dags since also partial trees (contexts) can be shared in the compression. In the first part efficient but complex algorithms for detecting applicability of a rewrite rule under STG-compression are constructed and analyzed. The second part applies these results to term rewriting sequences. The main result for submatching is that finding a redex of a left-linear rule can be performed in polynomial time under STG-compression. The main implications for rewriting and (single-position or parallel) rewriting steps are: (i) under STG-compression, n rewriting steps can be performed in nondeterministic polynomial time. (ii) under STG-compression and for left-linear rewrite rules a sequence of n rewriting steps can be performed in polynomial time, and (iii) for compressed rewrite rules where the left hand sides are either DAG-compressed or ground and STG-compressed, and an STG-compressed target term, n rewriting steps can be performed in polynomial time.

We study the effects of hyperons, delta baryons, and quark matter phase transitions on f-mode oscillations in neutron stars. Using the density-dependent relativistic mean-field model (DDME2) for the hadronic phase and the density-dependent quark mass (DDQM) model for the quark phase, we construct hadronic and hybrid equations of state (EoSs) consistent with astrophysical constraints. Including hyperons and delta baryons soften the EoS, reducing maximum masse, while phase transition to the quark matter further softens the EoS, decreasing the speed of sound and hence the maximum mass. f-mode frequencies, calculated using both the Cowling approximation and the general relativistic (GR) frameworks, reveal a significant overestimation by the Cowling method of about 10-30%, with discrepancies decreasing for more massive stars. We derive universal relations connecting the frequencies of the f-mode to the average density, compactness, and tidal deformability, finding significant deviations due to hyperons and delta baryons. Empirical relations for mass-scaled and radius-scaled frequencies are also provided, highlighting the importance of GR calculations for accurate modeling. These findings highlight the potential of gravitational wave asteroseismology to constrain neutron star EoSs and internal structure.

Molecular dynamics simulations are performed for a finite non-relativistic system of particles with Lennard-Jones potential. We study the effect of liquid-gas mixed phase on particle number fluctuations in coordinate subspace. A metastable region of the mixed phase, the so-called nucleation region, is analyzed in terms of a non-interacting cluster model. Large fluctuations due to spinodal decomposition are observed. They arise due to the interplay between the size of the acceptance region and that of the liquid phase. These effects are studied with a simple geometric model. The model results for the scaled variance of particle number distribution are compared with those obtained from the direct molecular dynamic simulations.

The initial conditions in the chemical non-equilibrated medium and Bjorken expanding medium at RHIC are determined. With a set of rate equations describing the chemical equilibration of quarks and gluons based on perturbative QCD, we investigate the consequence for parton evolution at RHIC. With considering parton evolution, it is shown that the Debye screening mass and the inverse mean free-path of gluons reduce with increasing proper time in the QGP medium. The parton evolution affects the parton energy loss with detailed balance, both parton energy loss from stimulated emission in the chemical non-equilibrated expanding medium and in Bjorken expanding medium are linear dependent on the propagating distance rather than square dependent in the static medium. The energy absorption can not be neglected at intermediate jet energies and small propagating distance of the energetic parton in contrast with that it is important only at intermediate jet energy in the static medium. This will increase the energy and propagating distance dependence of the parton energy loss and will affect the shape of suppression of moderately high P_T hadron spectra.

We study the kinetic and chemical equilibration in 'infinite' parton-hadron matter within the Parton-Hadron-String Dynamics transport approach, which is based on a dynamical quasiparticle model for partons matched to reproduce lattice-QCD results - including the partonic equation of state - in thermodynamic equilibrium. The 'infinite' matter is simulated within a cubic box with periodic boundary conditions initialized at different baryon density (or chemical potential) and energy density. The transition from initially pure partonic matter to hadronic degrees of freedom (or vice versa) occurs dynamically by interactions. Different thermodynamical distributions of the strongly-interacting quark-gluon plasma (sQGP) are addressed and discussed.

In this work the SMASH model is presented ("Simulating Many Accelerated Strongly-Interacting Hadrons"), a next-generation hadronic transport approach, which is designed to describe the non-equilibrium evolution of hadronic matter in heavy-ion collisions. We discuss first dilepton spectra obtained with SMASH in the few-GeV energy range of GSI/FAIR, where the dynamics of hadronic matter is dominated by the production and decay of various resonance states. In particular we show how electromagnetic transition form factors can emerge in a transport picture under the hypothesis of vector-meson dominance.

We discuss possible avenues to study fission dynamics starting from a time-dependent mean-field approach. Previous attempts to study fission dynamics using the time-dependent Hartree-Fock (TDHF) theory are analyzed. We argue that different initial conditions may be needed to describe fission dynamics depending on the specifics of the fission phenomenon and propose various approaches towards this goal. In particular, we provide preliminary calculations for studying fission following a heavy-ion reaction using TDHF with a density contraint. Regarding prompt muon-induced fission, we also suggest a new approach for combining the time-evolution of the muonic wave function with a microscopic treatment of fission dynamics via TDHF.

We present the first nuclear cross-section measurements of (p,{\gamma}) and (p,n) reactions on 118Te at energies relevant for the {\gamma}-process nucleosynthesis. Absolute cross-section values for center-of-mass energies of 6, 7 and 10 MeV are provided, together with a theoretical extrapolation to the Gamow window. This experiment marks the first time that direct proton-induced reactions have been measured on a radioactive ion beam at the Experimental Storage Ring (ESR) at GSI, Darmstadt. This paves the way for a large variety of measurements, delivering new constraints for explosive nucleosynthesis and for physics beyond nuclear stability.

We demonstrate the suitability of tensor network techniques for describing the thermal evolution of lattice gauge theories. As a benchmark case, we have studied the temperature dependence of the chiral condensate in the Schwinger model, using matrix product operators to approximate the thermal equilibrium states for finite system sizes with non-zero lattice spacings. We show how these techniques allow for reliable extrapolations in bond dimension, step width, system size and lattice spacing, and for a systematic estimation and control of all error sources involved in the calculation. The reached values of the lattice spacing are small enough to capture the most challenging region of high temperatures and the final results are consistent with the analytical prediction by Sachs and Wipf over a broad temperature range.

We introduce a well-defined and unbiased measure of the strength of correlations in quantum many-particle systems which is based on the relative von Neumann entropy computed from the density operator of correlated and uncorrelated states. The usefulness of this general concept is demonstrated by quantifying correlations of interacting electrons in the Hubbard model and in a series of transition-metal oxides using dynamical mean-field theory.

We study spherically symmetric configurations of the quadratic $f(R)$ gravity in the Einstein frame. In case of a purely gravitational system, we have determined the global qualitative behavior of the metric and the scalaron field for all static solutions satisfying the conditions of asymptotic flatness. These solutions are proved to be regular everywhere except for a naked singularity at the center; they are uniquely determined by the total mass $\mathfrak{M}$ and the "scalar charge" $Q$ characterizing the strength of the scalaron field at spatial infinity. The case $Q=0$ yields the Schwarzschild solution, but an arbitrarily small $Q\ne 0$ leads to the appearance of a central naked singularity having a significant effect on the neighboring region, even when the space-time metric in the outer region is practically insensitive to the scalaron field. Approximation procedures are developed to derive asymptotic relations near the naked singularity and at spatial infinity, and the leading terms of the solutions are presented. We investigate the linear stability of the static solutions with respect to radial perturbations satisfying the null Dirichlet boundary condition at the center and numerically estimate the range of parameters corresponding to stable/unstable configurations. In particular, the configurations with sufficiently small $Q$ turn out to be linearly unstable.