Pair production by a constant external field in noncommutative QED

In this Letter we study QED on the noncommutative space in the constant electromagnetic field background. Using the explicit solutions of the noncommutative version of Dirac equation in such background, we show that there are well-defined in- and out-going asymptotic states and also there is a causal Green's function. We calculate the pair production rate in this case. We show that at tree level noncommutativity will not change the pair production and the threshold electric field. We also calculate the pair production rate considering the first loop corrections. In this case we show that the threshold electric field is decreased by the noncommutativity effects. (C) 2001 Published by Elsevier Science B.V.