A New Phase at Finite Quark Density from AdS/CFT

Abstract

We explore phases of N=2 super Yang-Mills theory at finite quark density by introducing quark chemical potential in a D3-D7 setup. We formulate the thermodynamics of brane embeddings and find that we need to renormalize the finite chemical potential due to the divergence of the thermodynamic potentials and we find that the density versus chemical potential equation of state has rich structure. This yields two distinct first order phase transitions in a small window of quark density. In order words, there is a new first order phase transition in the region of deconfined quarks. In this new phase, the chemical potential is a decreasing function of the density. We suggest that this might be relevant to the difference in sQGP--wQGP phases of QCD.

Figures (7)

• Figure 1: Brane embedding and phase transitions. Solid lines: Minkowski embedding (red) to black hole embedding (blue). Dashed lines: Hopping from a black hole embedding to another one.
• Figure 2: Free energy vs. $L$ for fixed $Q$. The second phase transition is indicated by small kink near U'.
• Figure 3: Free energy vs. $L$ for fixed $Q$ around the second phase transition point.
• Figure 4: Phase diagram in $T$-$\tilde{Q}$ plane.
• Figure 5: $T$-$\tilde{Q}$ phase diagram around the new phase boundary.