# SIS

## Seminar

### Bulk filling branes and gravity back reaction for finite baryon number density

Seminar Room 1, Newton Institute

#### Abstract

It has been believed that charged black hole is not relevant to the BARYON density. Here we suggest that it is relevant in the case where the brane is filling the whole AdS bulk: in high temperature, the background becomes RN-$AdS$ black hole as a consequence of the gravity back reaction to the presence of charge. We show that the main difference of R-charge and baryon charge lies on the strength of couplings to the gravity: the latter is suppressed by $N_f/N_c$ relative to the former. With such gravity back reaction, density dependence of physical quantities can be encoded in quadratic action of AdS/QCD without adding higher order $\alpha'$ correction. We discuss phase diagram based on this picture with flat boundary and show that the phase diagram closes at the finite density or chemical potential unlike the brane embedding approach without gravity back reaction.