Pseudo-differential operators with nonlinear quantizing functions

Abstract

In this paper we develop the calculus of pseudo-differential operators corresponding to the quantizations of the form $$ Au(x)=\int_{\mathbb{R}^n}\int_{\mathbb{R}^n}e^{i(x-y)\cdotξ}σ(x+τ(y-x),ξ)u(y)dydξ, $$ where $τ:\mathbb{R}^n\to\mathbb{R}^n$ is a general function. In particular, for the linear choices $τ(x)=0$, $τ(x)=x$, and $τ(x)=\frac{x}{2}$ this covers the well-known Kohn-Nirenberg, anti-Kohn-Nirenberg, and Weyl quantizations, respectively. Quantizations of such type appear naturally in the analysis on nilpotent Lie groups for polynomial functions $τ$ and here we investigate the corresponding calculus in the model case of $\mathbb{R}^n$. We also give examples of nonlinear $τ$ appearing on the polarised and non-polarised Heisenberg groups, inspired by the recent joint work with Marius Mantoiu.