Recursive approach to determine correlation functions in multibaryon systems

We propose a recursive algorithm for the calculation of multibaryon correlation functions that combines the advantages of a recursive approach with those of the recently proposed unified contraction algorithm. The independent components of the correlators are built recursively by adding the baryons one after the other in a given order. The list of nonzero independent components is also constructed in a recursive manner, significantly reducing the resources required for this step. We computed the number of operations required to calculate the correlators up to Be-8, and observed a significant speedup compared to other techniques. For the calculation of He-4 and Be-8 correlation functions in the fully relativistic case O(10(8)) operations are required, whereas for nonrelativistic operators this number can be reduced to, e.g., O(10(4)) in the case of He-4.