Casimir energies due to matter fields in T2 and T2/Z2 compactifications Original Research Article

We calculate the Casimir energies due to matter fields with various boundary conditions along two compact directions in T2 compactification. We discuss whether the Casimir energies generate attractive or repulsive forces. On the theories with extra dimensions, the Casimir energy plays a crucial role in the mechanism for stabilizing the size of extra dimensions. Finally we argue a procedure of the application to Z2 orbifold.