Shift Theorem Involving the Exponential of a Sum of Non-Commuting   Operators in Path Integrals
  We consider expressions of the form of an exponential of the sum of two non-commuting operators of a single variable inside a path integration. We show that it is possible to shift one of the non-commuting operators from the exponential to other functions which are pre-factors and post-factors when the domain of integration of the argument of that function is from -\infty to +\infty. This shift theorem is useful to perform certain integrals and path integrals involving the exponential of sum of two non-commuting operators. 
Fred Cooper (NSF, Wash., D.C.), Gouranga C. Nayak (SUNY, Stony Brook)