QUANTUM NUMBERS OF THE THETA-VACUUM IN (2-DIMENSIONAL SPINOR ELECTRODYNAMICS - CHARGE AND MAGNETIC-FLUX(1))

A singular configuration of an external static vector field in the for m of a magnetic string polarizes the vacuum of a second-quantized theo ry on the plane orthogonal to the string axis. The most general bounda ry conditions at the punctured singular point that are compatible with the self-adjointness of two-dimensional Dirac Hamiltonian are conside red. The dependences of the induced vacuum quantum numbers on the para meter of the self-adjoint extension, on the string flux, and on the ch oice of irreducible representation of the gamma matrices in (2 + 1)-di mensional spacetime are discussed.