Strong-field Breit-Wheeler pair production in QED2+1.

The Breit-Wheeler pair production process in 2+1 dimensional spacetime is investigated. In the perturbative regime, nonvanishing rates at the energy threshold are found when odd numbers of photons take part in the reaction. This behavior is understood as a direct consequence of the reduced dimensionality and resembles a corresponding prediction made in gapped graphene monolayers. In the nonperturbative strong field regime, the effect of the dimensionality manifests itself in a different rate dependence on the quantum nonlinearity parameter. The consequence of this deviation is discussed briefly in line with the applicability of perturbation theory. We argue that, in addition to large values of the quantum nonlinearity parameter, the super-renormalizable character of quantum electrodynamics in 2+1 dimensional spacetime might give rise to a breakdown of perturbation theory within certain energy scales. [ABSTRACT FROM AUTHOR]