  Adopting the gauge-invariant but path-dependent variables formalism, we study
the coupling of torsion fields with photons in the presence of an external
background electromagnetic. We explicitly show that, in the case of a constant
electric field strength expectation value, the static potential remains
Coulombic, while in the case of a constant magnetic field strength expectation
value a confining potential is obtained. This result displays a marked
qualitative departure from the usual coupling of axionlike particles with
photons in the presence of an external magnetic field.
