Photon Mediated Energy Transfer from First Principles
In many photonic devices based on localized optically active defects in solids, the interaction of the defects with surrounding additional intrinsic or extrinsic impurities provides several important pathways for decoherence and trapping. Amongst these, photon mediated resonance energy transfer (RET) can occur at large separations of ～10 to 100 nanometers. In the near field regime RET can provide breaking of transition rules that are valid in the far field regime and can result in spin-non conserving absorption of light. Quantitative and predictive estimates of RET rates from first principles are essential to understand decoherence and trapping in quantum memories and they are central to designing ultra-high density atomic optical memories.
PyRET: a Python package for Resonance Energy Transfer (RET)
PyRET is an open-source python library to compute resonance energy transfer rates. It uses many-body localized states obtained from first principles electronic structure calculations and a near field description of nonrelativistic macroscopic quantum electrodynamics to estimate near field RET processes between arbitrary localized defects in solids. PyRET uses a fully general quantized multipolar basis to describe the photon modes and the Pauli-Fierz Hamiltonian to describe light matter interaction. PyRET works with electron wavefunctions obtained from plane wave density functional theory codes such as Quantum ESPRESSO, and can be coupled with quantum defect embedding theory, as implemented in West to include the multireference nature of electronic states.
- "First-Principles Investigation of near-Field Energy Transfer between Localized Quantum Emitters in Solids", S. Chattaraj, S. Guha, and G. Galli, Phys. Rev. Research 6, 033170 (2024).
- "Energy Transfer between Localized Emitters in Photonic Cavities from First Principles", S. Chattaraj and G. Galli, Phys. Rev. Research 7, 033229 (2025).