Minkowski-space formulation of two-pseudoparticle processes

We generalize the Minkowski-space picture of tunneling due to an instanton to include tunnelings centered at two spatially separated points. Our formalism leads to a two-parameter effective Lagrangian and contains as special cases the two-instanton, two--anti-instanton, and instanton--anti-instanton processes. We evaluate the tunneling amplitude in the WKB approximation for the case of widely separated tunneling locations and recover the Euclidean dilute-gas result