Pion polarizability from four-point functions in Lattice QCD

We study the electric polarizability of a charged pion from four-point functions in lattice QCD as an alternative to the background field method. The low-energy behavior of Compton scattering amplitude is matched to matrix elements of current-current correlation functions on the lattice. Lattice four-point correlation functions are constructed from quark and gluon fields to be used in Monte Carlo simulations. The elastic form factor (charge radius) is needed in the method which can be obtained from the same four-point functions at large current separations. Preliminary results from the connected quark-line diagrams will be presented.