Quantum Coherent Energy Transfer over Varying Pathways in Single Light-Harvesting Complexes

  title={Quantum Coherent Energy Transfer over Varying Pathways in Single Light-Harvesting Complexes},
  author={Richard Hildner and Daniel M. Brinks and Jana B. Nieder and Richard J. Cogdell and Niek F. van Hulst},
  pages={1448 - 1451}
Coherence in Photosynthesis It is unclear how energy absorbed by pigments in antenna proteins is transferred to the central site of chemical catalysis during photosynthesis. Hildner et al. (p. 1448) observed coherence—prolonged persistence of a quantum mechanical phase relationship—at the single-molecule level in light-harvesting complexes from purple bacteria. The results bolster conclusions from past ensemble measurements that coherence plays a pivotal role in photosynthetic energy transfer… 
Long-range quantum coherence of the photosystem 2 complexes in living cyanobacteria
Vacuum Rabi splitting in the transmission and fluorescence spectra is observed as a result of strong light matter coupling of the chlorophyll and the resonator modes, providing evidence that a delocalized polaritonic state is the basis of the extremely high energy transfer efficiency under natural conditions.
Quantum Coherent Excitation Energy Transfer by Carotenoids in Photosynthetic Light Harvesting.
It is reported that broad-band two-dimensional electronic spectroscopy indeed reveals the initial presence of exciton relaxation pathways that enable transfer of excitation from peridinin to chlorophyll a in <20 fs, but the quantum coherence that permits this is very short-lived.
Structure and Efficiency in Bacterial Photosynthetic Light-Harvesting.
This model describes the experimentally observed high efficiency of light harvesting, despite the absence of long-range quantum coherence, and helps explain the high transport efficiency in organisms with widely differing antenna structures, and suggests new design criteria for artificial light-harvesting devices.
Coherent phenomena in photosynthetic light harvesting: part two—observations in biological systems
Part Two of this review aims to provide an overview of experimental observations of energy transfer in the most studied light harvesting systems, and a consensus is emerging that most long-lived coherent phenomena are of vibrational or vibronic origin, where the latter may result in coherent excitation transport within a protein complex.
Observation of robust energy transfer in the photosynthetic protein allophycocyanin using single-molecule pump–probe spectroscopy
It is suggested that energy transfer is robust to protein fluctuations, a prerequisite for efficient light harvesting, and single-molecule pump–probe spectroscopy is applied to the ultrafast dynamics of single allophycocyanin, a light-harvesting protein from cyanobacteria.
Single-Molecule Fluorescence Spectroscopy of Photosynthetic Systems.
This review presents an overview of the common techniques for single-molecule fluorescence spectroscopy applied to photosynthetic systems and describes selected experiments that provide a new understanding of the impact of heterogeneity on light harvesting and thus how these systems are optimized to capture sunlight under physiological conditions.
Single-molecule spectroscopy of photosynthetic proteins in solution: exploration of structure–function relationships
In photosynthetic light harvesting, absorbed photoenergy transfers through networks of pigment–protein complexes to a central location, known as the reaction center, for conversion to chemical
Coherent Processes in Photosynthetic Energy Transport and Transduction
The role of non-trivial quantum mechanical effects in biology, and especially photosynthesis, has been the subject of intense hype and scrutiny over the past decade. This is largely the product of an
Light harvesting in a fluctuating antenna.
A simple conceptual model describing excitation diffusion in a continuous medium and accounting for possible variations of the excitation transfer rates is proposed and in a straightforward way solves various contradictions currently existing in the literature.
Spectroscopic Investigations of Light-Harvesting 2 Complexes from Rps. acidophila
A better understanding of light capturing and energy transfer processes in natural photosynthesis can contribute to the development of a highly efficient, artificial, molecular-based technology that


Quantum coherence spectroscopy reveals complex dynamics in bacterial light-harvesting complex 2 (LH2)
  • E. Harel, G. Engel
  • Physics, Chemistry
    Proceedings of the National Academy of Sciences
  • 2012
This work provides experimental evidence of long-lived quantum coherence between the spectrally separated B800 and B850 rings of the light-harvesting complex 2 (LH2) of purple bacteria and suggests that quantum mechanical interference between different energy transfer pathways may be important even at ambient temperature.
Long-lived quantum coherence in photosynthetic complexes at physiological temperature
Evidence that quantum coherence survives in FMO at physiological temperature for at least 300 fs, long enough to impact biological energy transport is presented, proving that the wave-like energy transfer process discovered at 77 K is directly relevant to biological function.
Evidence for wavelike energy transfer through quantum coherence in photosynthetic systems
Previous two-dimensional electronic spectroscopy investigations of the FMO bacteriochlorophyll complex are extended, and direct evidence is obtained for remarkably long-lived electronic quantum coherence playing an important part in energy transfer processes within this system is obtained.
Coherently wired light-harvesting in photosynthetic marine algae at ambient temperature
Observations provide compelling evidence for quantum-coherent sharing of electronic excitation across the 5-nm-wide proteins under biologically relevant conditions, suggesting that distant molecules within the photosynthetic proteins are ‘wired’ together by quantum coherence for more efficient light-harvesting in cryptophyte marine algae.
Bacterial photosynthesis begins with quantum-mechanical coherence.
A general formula for the rate constant of EET is developed, which is a formula in the weak-interaction limit, and so is Förster's formula, but it correctly takes into account the above size effect.
Photosynthetic light-harvesting is tuned by the heterogeneous polarizable environment of the protein.
A combined quantum chemical/molecular mechanical approach to compute electronic couplings that accounts for the heterogeneous dielectric nature of the protein-solvent environment in atomic detail is presented and it is found that dielectrics can profoundly tune by a factor up to ∼4 the energy migration rates between chromophore sites compared to the average continuum dielectic view that has historically been assumed.
Coherence Dynamics in Photosynthesis: Protein Protection of Excitonic Coherence
The results suggest that correlated protein environments preserve electronic coherence in photosynthetic complexes and allow the excitation to move coherently in space, enabling highly efficient energy harvesting and trapping in photosynthesis.
Quantum control of energy flow in light harvesting
Coherent light sources have been widely used in control schemes that exploit quantum interference effects to direct the outcome of photochemical processes. The adaptive shaping of laser pulses is a
Environment-assisted quantum walks in photosynthetic energy transfer.
A theoretical framework for studying the role of quantum interference effects in energy transfer dynamics of molecular arrays interacting with a thermal bath within the Lindblad formalism is developed and an effective interplay between the free Hamiltonian evolution and the thermal fluctuations in the environment is demonstrated.
Coherent picosecond exciton dynamics in a photosynthetic reaction center.
Two-dimensional electronic spectroscopy is applied to assess the role of coherences in the photoresponse of the bacterial reaction center of Rhodobacter sphaeroides and provides a mechanism for effective delocalization of the excitations on the picosecond time scale by electronic coherence.