In Vivo Probing of Quantum Coherence in Bacterial Photosynthesis
Abstract
This project aimed to employ the first spatially-resolved multidimensional spectroscopy to enable the elucidation of quantum effects in biological systems. Using purple sulfur photosynthetic bacteria as a model system, we aimed to understand the physical origin of recently observed quantum coherence in photosynthetic antennae complexes and to determine its importance for efficient energy transfer. In our previous AFOSR-funded work we developed fluorescence-based multidimensional spectroscopies to enable extensive characterization of coherent dynamics in isolated photosynthetic complexes and in vivo in purple bacterial cells. Here we used the approach to demonstrate that the method can resolve growth-dependent changes in the excitonic structure of purple bacteria in vivo. We also performed theoretical work to model the fluorescence-detected two dimensional electronic spectroscopy (F-2DES) data from these systems. In addition we have observed coherence in the LH2 complex of purple bacteria and have extensively characterized it. We find that the coherence is largely electronic in nature, with a rapid approx. 30 fs dephasing time, making it unlikely that it plays a role in energy transfer processes which occur on a approx. picosecond timescale. Our measurements pose a challenge to theoretical and computational approaches to capture the observed quantum and non-equilibrium phenomena. With an understanding of the key design elements of biological systems that exploit quantum effects to optimize their function, it may be possible to mimic such design principles in artificial materials for energy capture, conversion and human use.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 21, 2019
- Accession Number
- AD1086100
Entities
People
- Jennifer P Ogilvie
Organizations
- Board of Regents of the University of Michigan