Lp estimates for Riesz transforms associated to Schrodinger operators with discontinuous coefficients

This paper is devoted to the Lp boundedness of the Riesz transform associated to the Schrodinger operator in divergence form L=-div(A del)+V. More precisely, we get the result that del L-1/2fLp(Rn)<= CfLp(Rn) for all 1<p<infinity, if L is real symmetric with bounded, measurable, BMO theta(rho) coefficients on Rn and the non-negative potential V belongs to certain reverse Holder class.