The projection spectral theorem, quasi-free states and point processes
Eugene Lytvynov
TL;DR
The article surveys how point processes on a locally compact Polish space arise as joint spectral measures of particle densities associated with CAR/CCR representations in Fock spaces endowed with quasi-free vacuum states. It synthesizes the projection spectral theorem with the $K$-transform framework to connect operator families and their correlation measures to concrete point processes, including Poisson, determinantal, permanental, and hafnian types. By detailing both the general spectral machinery and explicit kernel-based constructions (Hermitian and $J$-Hermitian), the work clarifies how quasi-free states encode correlation structures and yield configuration-space measures. The findings provide a rigorous bridge between infinite-dimensional harmonic analysis, operator algebras, and stochastic point processes, enabling systematic derivations of point-process models from quantum-like particle-density formalisms.
Abstract
In this review paper, we demonstrate that several classes of point processes in a locally compact Polish space $X$ appear as the joint spectral measure of a rigorously defined particle density of a representation of the canonical anticommutation relations (CAR) or the canonical commutation relations (CCR) in a Fock space. For these representations of the CAR/CCR, the vacuum state on the corresponding $*$-algebra is quasi-free. The classes of point process that arise in such a way include determinantal and permanental point processes.
