Promotor: dr hab. Michał Spaliński, prof.UwB- Wydział Fizyki UwB Narodowe Centrum Badań Jądrowych

A Holographic Perspective on Strongly Interacting Matter Properties at Finite Temperatures and Densities.

I recenzent: prof. dr hab. Romuald Janik - Instytut Fizyki UJ

II recenzent: prof. dr hab. Zygmunt Lalak - Instytut Fizyki Teoretycznej UW

The main theme of this dissertation is the physics of strongly interacting matter at fnite temperatures and fnite baryon densities. The results presented were obtained using methods of gauge/gravity duality and a particular generalization of the Nambu-Jona-Lasinio model. The inspiration for these studies came from two physical questions pertaining to the phase diagram of quantum chromodynamics. The frst concerns the region of intermediate baryon density and low temperature, where the so-called quarkyonic phase has been conjectured to appear. The second addresses the behaviour of the chiral condensate at fnite temperature. Large-N QCD matter at intermediate baryon density and low temperatures has been con-jectured to be in the so-called quarkyonic phase, i.e., to have a quark Fermi surface and on top of it a confned spectrum of excitations. It has been suggested that the presence of the quark Fermi surface leads to a homogeneous phase with restored chiral symmetry, which is unstable towards creating condensates breaking both the chiral and translational symmetry. Motivated by these exotic features, we investigate properties of cold baryonic matter in the single avor Sakai-Sugimoto model searching for a holographic realization of the quarkyonic phase. The second question concerns the behaviour fnite temperature chiral condensate for 2 + 1 quark avors. It is considered in the framework of the hadron resonance gas model. This requires some dynamical information; specifcally the hadronic sigma terms which express the dependence of the hadron spectrum on the current quark masses. For this, various non-perturbative evective methods are employed { based on the holographic model os Sakai and Sugimoto, and on the Nambu-Jona Lasinio model. Using these insights, hadronic sigma terms are discussed in the context of recent frst principles results following from lattice QCD and chiral perturbation theory. For the condensate, in generic agreement with lattice data it is found that chiral symmetry restoration in the strange quark sector takes place at higher temperatures than in the light quark sector. The importance of this result for a recently proposed dynamical model of hadronic freeze-out is outlined.
streszczenie, recenzja - prof. Janik, recenzja - prof. Lalak