Dense matter in a holographic hard-wall model of QCD

Fujii, Daisuke; Hosaka, Atsushi*; Iwanaka, Akihiro*; Sakai, Tadakatsu*; Tachibana, Motoi*

Understanding the behavior of QCD matter under strong coupling remains a difficult task due to its inherently non-perturbative character. In this context, we investigate a two-flavor hard-wall holographic model to explore finite-density QCD at zero temperature, incorporating effects from a nonzero quark mass. The dense matter phase is described by solving the classical equations of motion within a homogeneous ansatz. To establish a connection between the bulk gravity theory and boundary QCD observables, we perform holographic renormalization and formulate the corresponding holographic dictionary. In analyzing the phase structure, we highlight the importance of introducing an IR boundary term at the hard-wall cutoff. Within this setup, we identify a phase of baryonic matter characterized by a large baryon number density and a significantly reduced chiral condensate. We derive the equation of state for this phase and use it to compute the mass-radius relation for neutron stars.