D7-anti-D7 bilayer: holographic dynamical symmetry breaking
  We consider a holographic model of dynamical symmetry breaking in 2+1-dimenisons, where a parallel D7-anti-D7 brane pair fuse into a single object, corresponding to the U(1)XU(1)->U(1) symmetry breaking pattern. We show that the current-current correlation functions can be computed analytically and exhibit the low momentum structure that is expected when global symmetries are spontaneously broken. We also find that these correlation functions have poles attributable to infinite towers of vector mesons with equally spaced masses. 
Gianluca Grignani, Namshik Kim, Gordon W. Semenoff
hep-th cond-mat.str-el