Connecting bright and dark states through accidental degeneracy caused by lack of symmetry

Abstract

Coupled excitonic structures are found in natural and artificial light harvesting systems where optical transitions link different excitation manifolds. In systems with symmetry, some optical transitions are allowed, while others are forbidden. Here we examine an excitonic ring structure and identify an accidental degeneracy between two categories of double-excitation eigenstates with distinct symmetries and optical transition properties. To understand the accidental degeneracy, a complete selection rule between two arbitrary excitation manifolds is derived with a physically motivated proof. Remarkably, symmetry analysis shows the lack of certain symmetry elements in the Hamiltonian is responsible for this degeneracy, which is unique to rings with size N=4l+2 (l being an integer).

References in corpus (5)

• Environment-Assisted Quantum Walks in Photosynthetic Energy Transfer
• Highly efficient energy excitation transfer in light-harvesting complexes: The fundamental role of noise-assisted transport
• Computational Methodologies and Physical Insights into Electronic Energy Transfer in Photosynthetic Light-Harvesting Complexes
• Hidden antiunitary symmetry behind "accidental" degeneracy and its protection of degeneracy
• Dark states and delocalization: competing effects of quantum coherence on the efficiency of light harvesting systems

Cited by in corpus (5)

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• WaveTrain: A Python Package for Numerical Quantum Mechanics of Chain-Like Systems Based on Tensor Trains
• Survival probability of the Grover walk on the ladder graph
• Solving the time-independent Schrödinger equation for chains of coupled excitons and phonons using tensor trains