1111.0199 (E. R. Bezerra de Mello et al.)

Fermionic Casimir densities in a conical space with a circular boundary
and magnetic flux    [PDF]

E. R. Bezerra de Mello, F. Moraes, A. A. Saharian

The vacuum expectation value (VEV) of the energy-momentum tensor for a
massive fermionic field is investigated in a (2+1)-dimensional conical
spacetime in the presence of a circular boundary and an infinitely thin
magnetic flux located at the cone apex. The MIT bag boundary condition is
assumed on the circle. At the cone apex we consider a special case of boundary
conditions for irregular modes, when the MIT bag boundary condition is imposed
at a finite radius, which is then taken to zero. The presence of the magnetic
flux leads to the Aharonov-Bohm-like effect on the VEV of the energy-momentum
tensor. For both exterior and interior regions, the VEV is decomposed into
boundary-free and boundary-induced parts. Both these parts are even periodic
functions of the magnetic flux with the period equal to the flux quantum. The
boundary-free part in the radial stress is equal to the energy density. Near
the circle, the boundary-induced part in the VEV dominates and for a massless
field the vacuum energy density is negative inside the circle and positive in
the exterior region. Various special cases are considered.

View original: http://arxiv.org/abs/1111.0199