Fermionic Casimir effect in an external magnetic field
  The influence of an external constant uniform magnetic field on the Casimir energy density of a Dirac field under antiperiodic (and periodic) boundary condition is computed by applying Schwinger's proper time method. The result thus obtained shows that in principle, under suitable conditions, the magnetic field can enhance the fermionic Casimir energy density. 
M. V. Cougo-Pinto, C. Farina, A. C. Tort