Year: 2026
Type: article
Abstract: Collective emission in light-harvesting assemblies is governed by the local transition dipole and finite geometry of emitting units. To capture this, we develop a non-Hermitian Hamiltonian using the quantum electrodynamic dyadic Green’s tensor for a purple bacteria. We construct it for the isolated 24-bacteriochlorophyll conical frustum and its P4212 crystallographic assembly. The P4212 unit-cell symmetry is found to invert the bright-dark ordering of the single ring, placing subradiant states at the low-energy end and revealing the entire crystal to be the energy-harvesting entity. Tilt-driven switching is activated only in crystal geometries where the finite dipole-carrier (LH2) lies perpendicular to the growth plane. Vacancy and orientational disorder work only in cooperation to renormalize the switching threshold from higher polar angles to lower values.
Authors: Javed Akhtar, Himangshu Prabal Goswami
Institution: Gauhati University
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7164359122