Multipolar hierarchy of efficient quantum polarization measures
  We advocate a simple multipole expansion of the polarisation density matrix. The resulting multipoles appear as successive moments of the Stokes variables and can be obtained from feasible measurements. In terms of these multipoles, we construct a whole hierarchy of measures that accurately assess higher-order polarization fluctuations. 
P. de la Hoz, A. B. Klimov. G. Bjork, Y.-H. Kim, C. Muller, Ch.   Marquardt, G. Leuchs and L. L. Sanchez-Soto
quant-ph