On the Lieb--Wehrl Entropy conjecture for $SU(N,1)$

TL;DR

This paper extends the proof of Lieb's conjecture on Wehrl entropy to the group $SU(N,1)$, providing sharp inequalities for coherent state transforms and exploring related isoperimetric and Faber--Krahn inequalities.

Contribution

It generalizes the Lieb conjecture resolution to $SU(N,1)$ and extends related inequalities within the Bergman space framework.

Findings

Established sharp functional inequalities for $SU(N,1)$ coherent states.

Extended the Faber--Krahn inequality to the Bergman space setting.

Connected isoperimetric assumptions to entropy minimization in complex hyperbolic spaces.

Abstract

We investigate the sharp functional inequalities for the coherent state transforms of $SU(N,1)$. These inequalities are rooted in Wehrl's definition of semiclassical entropy and his conjecture about its minimum value. Lieb resolved this conjecture in 1978, posing a similar question for Bloch coherent states of $SU(2)$. The $SU(2)$ conjecture was settled by Lieb and Solovej in 2014, and the conjecture was extended for a wide class of Lie groups. The generalized Lieb conjecture has been resolved for several Lie groups, including $SU(N),\, N\geq 2$, $SU(1,1)$, and its $AX+B$ subgroup. Under the Li--Su assumption on isoperimetric regions in the complex hyperbolic ball, our sharp functional inequalities for the coherent state transforms extend this resolution to $SU(N,1),\, N\geq 2$. Additionally, we explore the Faber--Krahn inequality, which applies to the short-time Fourier transform with a Gaussian window. This inequality was previously proven by Nicola and Tilli and later extended by Ramos and Tilli to the wavelet transform. In this paper, we further extend this result within the framework of the Bergman space $\mathcal{A}_{\alpha}$.