Year: 2026
Type: article
Abstract: Quantum optics characterizes light through photon correlations, motivating their connection to correlated ab initio molecular electronic structure. In this study, intracavity photon statistics of cavity-coupled molecules are computed from QED coupled-cluster (QED-CCSD-22) densities and validated against exact diagonalization of the Pauli-Fierz Hamiltonian. A change of coordinate origin or dipole convention displaces the ground state coherently, so second-order and higher cumulants of the cavity field are independent of these conventions even for molecular ions. The photon subsystem of QED Hartree-Fock is exactly coherent, so the invariant statistics describe fluctuations beyond this electron-photon product reference. The field fluctuations are super-Poissonian, and their degree of second-order coherence depends primarily on cavity frequency in the tested weak-coupling regime, falling from 18.5 to 4.9 for H2 as the cavity is detuned from 5 to 20 eV. The third cumulant identifies non-Gaussian fluctuations and changes sign under reversal of the coupling direction.
Source: The Journal of Chemical Physics
DOI: 10.1063/5.0357762
Author: Kurt R. Brorsen
Institution: University of Missouri
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G1523888516, G2713111100
OpenAlex ID: W7203931472