Energy functional for Lagrangian tori in $\mathbb{C}P^2$

Abstract

In this paper we study Lagrangian tori in ${\mathbb C}P^2$. A two-dimensional periodic Schr\"odinger operator is associated with every Lagrangian torus in ${\mathbb C}P^2$. We introduce an energy functional for tori as an integral of the potential of the Schr\"odinger operators, which has a natural geometrical meaning. We study the energy functional on two families of Lagrangian tori and propose a conjecture that the minimum of the functional is achieved by the Clifford torus. We also study deformations of minimal Lagrangian tori. In particular we show that if the deformation preserves a conformal type of the torus, then it also preserves the area of the torus. Thus it follows that deformations generated by Novikov-Veselov equations preserve the area of minimal Lagrangian tori.