Gravity seminar - Nicolas Kovensky Seminar

Abstract: We study the phase structure of the Witten-Sakai-Sugimoto model in the plane
of temperature and baryon chemical potential, including the effect of a nonzero current
quark mass. Our study is performed in the decompactified limit of the model, which, at
least regarding the chiral phase transition, appears to be closer to real-world QCD than the
original version. We account for the quark mass in an effective way
based on an open Wilson line operator whose expectation value is identified with the chiral
condensate. We find that the quark mass stabilizes a configuration with string sources
and point out that this phase plays an important role in the phase diagram. Furthermore,
we show that the quark mass breaks up the first-order chiral phase transition curve and
introduces critical points to the phase diagram. Finally, we discuss the similarities of the phase
structure to other holographic approaches and to lattice simulations of "heavy QCD".