Stark-Wannier Ladders and Cubic Exponential Sums

Alexander Fedotov, Frédéric Klopp

On L 2 (R), we consider the Schrödinger operator (1.1) H ǫ = -- $\partial$ 2 $\partial$x 2 + v(x) -- ǫx, where v is a real analytic 1-periodic function and ǫ is a positive constant…