Ground states and concentration phenomena for the fractional   Schr\"odinger equation
  We consider here solutions of the nonlinear fractional Schr\"odinger equation $$\epsilon^{2s}(-\Delta)^s u+V(x)u=u^p.$$ We show that concentration points must be critical points for $V$. We also prove that, if the potential $V$ is coercive and has a unique global minimum, then ground states concentrate suitably at such minimal point as $\epsilon$ tends to zero. In addition, if the potential $V$ is radial, then the minimizer is unique provided $\epsilon$ is small. 
Mouhamed Moustapha Fall, Fethi Mahmoudi, and Enrico Valdinoci
math.AP