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Probing Quantum Coherence in Bacterial Photosynthesis at the Ensemble and Single Complex Level

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Technical Report,01 May 2015,30 Apr 2018

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University of Michigan AnnArbor United States

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This project developed novel experimental spectroscopy and imaging approaches, at and below the diffraction limit, 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. Fluorescence-based two dimensional electronic spectroscopy F-2DES was developed to extensively characterize coherent dynamics at the ensemble and single photosynthetic complex level. F-2DES was shown to be a highly sensitive method for distinguishing between vibrational, electronic and vibronic coherence. Combined with confocal microscopy, the approach was used to resolve excitonic structure in live colonies of purple bacteria, and coherence in vivo. 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. The proposed research supports technological advances in application areas of interest to the United States Air Force.

Subject Categories:

  • Atomic and Molecular Physics and Spectroscopy
  • Quantum Theory and Relativity

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