Complex symplectomorphisms and pseudo-K\"ahler islands in the quantization of toric manifolds

TL;DR

This paper explores the relationship between different quantizations of toric manifolds via complexified Hamiltonian flows, revealing connections to K"ahler metrics with singularities and degeneracies.

Contribution

It introduces a novel approach linking toric K"ahler and real polarizations through analytic continuation of Hamiltonian flows, and describes associated singular and degenerate structures.

Findings

Quantization in different polarizations related by imaginary-time Hamiltonian flow.

Description of toric K"ahler metrics with cone singularities via imaginary times.

Asymptotic vanishing of quantum states in negative-definite regions.

Abstract

Let $P$ be a Delzant polytope. We show that the quantization of the corresponding toric manifold $X_{P}$ in toric K\"ahler polarizations and in the toric real polarization are related by analytic continuation of Hamiltonian flows evaluated at time $t = \sqrt{-1} s$. We relate the quantization of $X_{P}$ in two different toric K\"ahler polarizations by taking the time-$\sqrt{-1} s$ Hamiltonian "flow" of strongly convex functions on the moment polytope $P$. By taking $s$ to infinity, we obtain the quantization of $X_{P}$ in the (singular) real toric polarization. Recall that $X_{P}$ has an open dense subset which is biholomorphic to $({\mathbb{C}}^{*})^{n}$. The quantization of $X_{P}$ in a toric K\"ahler polarization can also be described by applying the complexified Hamiltonian flow of the Abreu--Guillemin symplectic potential $g$, at time $t=\sqrt{-1}$, to an appropriate finite-dimensional subspace of quantum states in the quantization of $T^{*}{\mathbb{T}}^{n}$ in the vertical polarization. By taking other imaginary times, $t= k \sqrt{-1}, k\in {\mathbb{R}}$, we describe toric K\"ahler metrics with cone singularities along the toric divisors in $X_{P}$. For convex Hamiltonian functions and sufficiently negative imaginary part of the complex time, we obtain degenerate K\"ahler structures which are negative definite in some regions of $X_{P}$. We show that the pointwise and $L^2$-norms of quantum states are asymptotically vanishing on negative-definite regions.