Consistency and Advantage of Loop Regularization Method Merging with   Bjorken-Drell's Analogy Between Feynman Diagrams and Electrical Circuits
  The consistency of loop regularization (LORE) method is explored in multiloop calculations. A key concept of the LORE method is the introduction of irreducible loop integrals (ILIs) which are evaluated from the Feynman diagrams by adopting the Feynman parametrization and ultraviolet-divergence-preserving(UVDP) parametrization. It is then inevitable for the ILIs to encounter the divergences in the UVDP parameter space due to the generic overlapping divergences in the 4-dimensional momentum space. By computing the so-called $\alpha\beta\gamma$ integrals arising from two loop Feynman diagrams, we show how to deal with the divergences in the parameter space with the LORE method. By identifying the divergences in the UVDP parameter space to those in the subdiagrams, we arrive at the Bjorken-Drell's analogy between Feynman diagrams and electrical circuits. The UVDP parameters are shown to correspond to the conductance or resistance in the electrical circuits, and the divergence in Feynman diagrams is ascribed to the infinite conductance or zero resistance. In particular, the sets of conditions required to eliminate the overlapping momentum integrals for obtaining the ILIs are found to be associated with the conservations of electric voltages, and the momentum conservations correspond to the conservations of electrical currents, which are known as the Kirchhoff's laws in the electrical circuits analogy. As an application to the massive scalar $\phi^4$ theory, it enables us to obtain the well-known logarithmic running of the coupling constant and the consistent power-law running of the scalar mass at two loop level. Especially, we present an explicit demonstration on the general procedure of applying the LORE method to the multiloop calculations of Feynman diagrams when merging with the advantage of Bjorken-Drell's circuit analogy. 
Da Huang, Yue-Liang Wu
hep-ph hep-th math-ph math.MP