Vacuum Expectation Values of Some Exponential Operators
R. J. Blomer · Progress of Theoretical Physics · 1970
The vacuum expectation values (VEV) of operators exp (A+B)n, n > 2, where [A, B] is a c-number are given as formal (divergent) power series. A generalization of the Borel summation is used to construct from those divergent power series the VEVs in integral representation which fulfill the requirements of generalized Padé approximation. A correspondence with the S-matrix elements in the Peres model is shown.