Conformal Phase Transitions at Weak and Strong Coupling

Understand

D3 and D7-branes intersecting in 2+1 dimensions give rise at low energies to N=4 supersymmetric Yang-Mills theory coupled to defect fermions in the fundamental representation.

• This theory undergoes a BKT-type phase transition from a conformal phase to one in which the fermions acquire a non-zero mass when the 't Hooft coupling of the N=4 SYM exceeds a critical value.
• To study this transition, we continue the parameters of the model to a regime where a gravitational description is valid.
• We use it to calculate the masses of mesons and the phase diagram as a function of temperature and chemical potential.