Quantum coherent energy transfer over varying pathways in single light-harvesting complexes

Science. 2013 Jun 21;340(6139):1448-51. doi: 10.1126/science.1235820.

Abstract

The initial steps of photosynthesis comprise the absorption of sunlight by pigment-protein antenna complexes followed by rapid and highly efficient funneling of excitation energy to a reaction center. In these transport processes, signatures of unexpectedly long-lived coherences have emerged in two-dimensional ensemble spectra of various light-harvesting complexes. Here, we demonstrate ultrafast quantum coherent energy transfer within individual antenna complexes of a purple bacterium under physiological conditions. We find that quantum coherences between electronically coupled energy eigenstates persist at least 400 femtoseconds and that distinct energy-transfer pathways that change with time can be identified in each complex. Our data suggest that long-lived quantum coherence renders energy transfer in photosynthetic systems robust in the presence of disorder, which is a prerequisite for efficient light harvesting.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / chemistry*
  • Bacteriochlorophyll A / chemistry*
  • Energy Transfer*
  • Fourier Analysis
  • Light
  • Light-Harvesting Protein Complexes / chemistry*
  • Photosynthesis
  • Quantum Theory
  • Rhodopseudomonas / chemistry*
  • Temperature

Substances

  • B800-850 light-harvesting complex, bacteria
  • Bacterial Proteins
  • Bacteriochlorophyll A
  • Light-Harvesting Protein Complexes