We point out that the problem of kaon condensation in dense hadronic matter can be addressed in perturbative QCD. Indeed, perturbative calculations suggest that negative kaons are condensed in high-density quark matter if the presence of electrons is taken into account. This observation sheds new light on the proposal that the low-density hyperon and high-density quark matter phases of QCD are ...

This is an attempt to summarize the theoretical talks given at the First International Conference ”Hard Probes ’04”, dedicated to the study of the properties of quark-gluon matter and its diagnostics with the hard processes. The talk covers the following topics: the structure of quark-gluon matter at finite temperature; the theory of nuclear wave functions at small Bjorken x; the propagation of...

The reason, we need three terms of ‘strange’, ‘bare’, and ‘solid’ before quark stars, is presented concisely though some fundamental issues are not certain. Observations favoring these stars are introduced. 1. Hadronic stability: why strange? Strange (quark) stars are quark stars with strangeness. What’s strangeness? Some peculiar cosmic ray events were discovered in 1947, with a strange nature...

We suggest a scenario where the three light quark flavors are sequentially deconfined under increasing pressure in cold asymmetric nuclear matter as, e.g., in neutron stars. The basis for our analysis is a chiral quark matter model of Nambu–Jona-Lasinio (NJL) type with diquark pairing in the spin-1 single flavor (CSL), spin-0 two flavor (2SC) and three flavor (CFL) channels. We find that nucleo...

Due to instabilities at the Fermi surface, matter composed of deconfined quarks is believed to be a color superconductor at low temperatures (see Refs. [1] and other reviews). While the precise value of the energy gap at astrophysical densities is yet indeterminate, calculations using models of vacuum physics generally predict a gap in the neighborhood of 100 MeV for densities at and above thre...

We have investigated the spectral function of light quarks in infinite quark matter using a simple, albeit selfconsistent model [1]. Relations between the spectral function and the collisional self-energies in the Born approximation were used to calculate the spectral function in an iterative process beyond the quasiparticle approximation. The quark interactions were described by the SU(2) Namb...

Thermodynamical properties of nuclear matter at sub-saturation densities were investigated using a simple van der Waals-like equation of state with an additional term representing the symmetry energy. First-order isospin-asymmetric liquid-gas phase transition appears restricted to isolated isospin-asymmetric systems while the symmetric systems will undergo fragmentation decay resembling the sec...

We show that within a recently developed nonlocal chiral quark model the critical density for a phase transition to color superconducting quark matter under neutron star conditions can be low enough for these phases to occur in compact star configurations with masses below 1.3 M⊙. We study the cooling of these objects in isolation for different values of the gravitational mass and argue that, i...

We explore the relevance of color superconductivity inside a possible quark matter core for the bulk properties of neutron stars. For the quark phase we use an Nambu–Jona-Lasinio (NJL) type model, extended to include diquark condensates. For the hadronic phase, a microscopic many-body model is adopted, with and without strangeness content. In our calculations, a sharp boundary is assumed betwee...

We explore the relevance of color superconductivity inside a possible quark matter core for the bulk properties of neutron stars. For the quark phase we use a Nambu–Jona-Lasinio (NJL) type model, extended to include diquark condensates. For the hadronic phase, a microscopic many-body model is adopted, with and without strangeness content. In our calculations, a sharp boundary is assumed between...