Photon emission in a constant magnetic field in 2+1 dimensional   space-time
  We calculate by the proper-time method the amplitude of the two-photon emission by a charged fermion in a constant magnetic field in (2+1)-dimensional space-time. The relevant dynamics reduces to that of a supesymmetric quantum-mechanical system with one bosonic and one fermionic degrees of freedom. 
J. T. S. Amaral (1), S. I. Zlatev (2) ((1) Universidade Federal do Rio   Grande do Sul (2) Universidade Federal de Sergipe)