Pion Velocity near the Chiral Phase Transition
  We focus on the pion velocity at the critical temperature and study the quantum and hadronic thermal effects based on the vector manifestation (VM). We show the non-renormalization property on the pion velocity $v_\pi$, which is protected by the VM, and estimate the value of $v_\pi$ to be close to the speed of light. 
Chihiro Sasaki