Zeldovich regularization refers to a regularization method to calculate divergent integrals and divergent series, that was first introduced by Yakov Zeldovich in 1961.
[1] Zeldovich was originally interested in calculating the norm of the Gamow wave function which is divergent since there is an outgoing spherical wave.
Zeldovich regularization uses a Gaussian type-regularization and is defined, for divergent integrals, by[2] and, for divergent series, by[3][4][5]