On the second Laplacian spectral moment of a graph
Kragujevac (M. L. Kragujevac: On the Laplacian energy of a graph, Czech. Math. J. () (2006), 1207–1213) gave the definition of Laplacian energy of a graph and proved ; equality holds if and only if . In this paper we consider the relation between the Laplacian energy and the chromatic number of a graph and give an upper bound for the Laplacian energy on a connected graph.