Information on the phase structure of strongly interacting matter at high baryon densities can be gained from observations neutron stars and their detailed analysis. In present work Bayesian inference methods are used to set constraints speed sound in interior stars, based recent multi-messenger data combination with limiting conditions nuclear physics low densities. Two general parametric representations introduced for $c_s$ order examine independence respect choices parametrisation Priors....

With the aim of exploring evidence for or against phase transitions in cold and dense baryonic matter, inference sound speed equation state matter neutron stars is extended view recent new observational data. The impact heavy ($2.35{M}_{\ensuremath{\bigodot}}$) black-widow pulsar PSR J0952-0607 unusually light supernova remnant HESS J1731-347 inspected. In addition, a detailed reanalysis performed low-density constraint based on chiral effective field theory perturbative QCD at...

As an update to our previously performed Bayesian inference analyses of the neutron star matter equation-of-state and related quantities, additional impact recently published NICER data PSR J0437-4751 is examined. Including mass radius distributions this pulsar in database results modest shifts from inferred median posterior values radii <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>R</a:mi></a:math> central densities <c:math...

Recent inference results of the sound velocity in cores neutron stars are summarized. Implications for equation state and phase structure highly compressed baryonic matter discussed. In view strong constraints imposed by heaviest known pulsars, must be very stiff order to ensure stability these extreme objects. This required stiffness limits possible appearance transitions star cores. For example, a Bayes factor analysis quantifies evidence squared velocities cs2&gt;0.1 2.1 solar-mass...

We propose a conceptual distinction between hard and soft realizations of deconfinement from nuclear to quark matter. In the high density region Hard Deconfinement repulsive cores baryons overlap each other bulk thermodynamics is dominated by core properties that can be experimentally accessed in high-energy scattering experiments. find equation state estimated single baryon fairly consistent with those empirically known neutron star phenomenology. next discuss novel concept Soft...

Updated constraints from neutron star masses and radii impose stronger restrictions on the equation of state for baryonic matter at high densities low temperatures. The existence $2{M}_{\ensuremath{\bigodot}}$ stars rules out many soft equations with prominent ``exotic'' compositions. present work reviews conditions required pressure as a function baryon density to satisfy these constraints. Several scenarios sufficiently stiff are evaluated. common starting point is realistic description...

A previous study of nuclear matter in a chiral nucleon-meson model is extended to isospin-asymmetric matter. Fluctuations beyond mean-field approximation are treated the framework functional renormalization group. The liquid-gas phase transition investigated detail as function proton fraction asymmetric equations state at zero temperature both symmetric and pure neutron found be good agreement with realistic many-body computations. We also density dependence pion mass medium. question...

The interaction between hyperons and nucleons has a wide range of applications in strangeness nuclear physics is topic continuing great interest. These interactions are not only important for hyperon-nucleon scattering but also essential as basic input to studies hyperon-nuclear few- many-body systems including hypernuclei neutron star matter. We review the systematic derivation construction such baryonic forces from symmetries quantum chromodynamics within non-relativistic SU(3) chiral...

The equation of state (EoS) neutron star matter, constrained by the existence two-solar-mass stars and gravitational wave signals from mergers, is analyzed using Landau theory relativistic Fermi liquids. While phase diagram dense cold QCD matter still open for scenarios ranging hadronic to quark in center stars, a Fermi-liquid treatment motivated microscopic approach starting chiral nucleon-meson field combined with nonperturbative functional renormalization group methods. In this scheme...

The chiral nucleon-meson model, previously applied to systems with equal number of neutrons and protons, is extended asymmetric nuclear matter. Fluctuations are included in the framework functional renormalization group. equation state for pure neutron matter studied compared recent advanced many-body calculations. condensate computed as a function baryon density. It found that, once fluctuations incorporated, restoration transition shifted high densities, much beyond three times density normal

This study is performed with the aim of gaining insights into possible applicability quark-hadron continuity concept, not only in idealized case three-flavor symmetric quark matter, but also for transition from neutron matter to two-flavor matter. A key issue between superfluidity and a corresponding superfluid phase produced by $d$-quark pairing. Symmetry arguments are developed relevant dynamical mechanisms analyzed. It pointed out that $^{3}{P}_{2}$ dense has direct analog pairing...

This presentation in two parts starts with a brief review on the speed of sound neutron star matter as inferred from observational data. It is pointed out that, view strong constraints imposed by observed properties heaviest stars, equation state must be very stiff. Stringent limits can set possible appearance phase transitions cores. The second part discusses issues concerning occurance strangeness degrees freedom, particular hyperons, stars. Here focus role repulsive hyperon-nuclear...