Factorization of numbers with Gauss sums: I. Mathematical background
  We use the periodicity properties of generalized Gauss sums to factor numbers. Moreover, we derive rules for finding the factors and illustrate this factorization scheme for various examples. This algorithm relies solely on interference and scales exponentially. 
S. W\"olk, W. Merkel, W. P. Schleich, I. Sh. Averbukh and B. Girard
quant-ph