Magnetic Field Effect on the Phase Transition in AdS Soliton Spacetime
  We investigate the scalar perturbations in an AdS soliton background coupled to a Maxwell field via marginally stable modes. In the probe limit, we study the magnetic field effect on the holographic insulator/superconductor phase transition numerically and analytically. The condensate will be localized in a finite circular region for any finite constant magnetic field. Near the critical point, we find that there exists a simple relation among the critical chemical potential, magnetic field, the charge and mass of the scalar field. This relation indicates that the presence of the magnetic field causes the phase transition hard. 
Rong-Gen Cai, Li Li, Hai-Qing Zhang and Yun-Long Zhang
hep-th gr-qc