Local dispersive and Strichartz estimates for the Schr{\"o}dinger operator on the Heisenberg group

It was proved by H. Bahouri, P. G{'e}rard and C.-J. Xu in [9] that the Schr{"o}dinger equation on the Heisenberg group ${\mathbb{H}}^d$, involving the sublaplacian, is an example of a totally non-dispersive evolution equation: for this reason global dispersive estimates cannot hold. This paper aims at establishing local dispersive estimates on ${\mathbb{H}}^d$ for the linear Schr{"o}dinger equation, by a refined study of the Schr{"o}dinger kernel $S_t$ on ${\mathbb{H}}^d$. The sharpness of these estimates is discussed through several examples. Our approach, based on the explicit formula of the heat kernel on ${\mathbb{H}}^d$ derived by B. Gaveau in [20], is achieved by combining complex analysis and Fourier-Heisenberg tools. As a by-product of our results, we establish local Strichartz estimates and prove that the kernel $S_t$ concentrates on quantized horizontal hyperplanes of ${\mathbb{H}}^d$.