How Quantum Coherence Assists Photosynthetic Light-Harvesting

Strümpfer, Johan; Sener, Melih; Schulten, Klaus

doi:10.1021/jz201459c

Cited by 180 publications

(274 citation statements)

References 67 publications

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“…Despite current attention to fine effects of underdamped intramolecular vibrational modes [24][25][26][27][28] and to details of spectral density shapes [29], and despite recent efforts to introduce a paradigm shift in understanding of the origin of the photosynthetic EET efficiency [30][31][32], the overall picture of this process, as drawn by the master equations of the Förster and Redfield types, remains valid [33] (see e. g. [34] for quantitative results). Recent theoretical advances enabling exact numerical solutions of some types of energy transfer problems e.g.…”

Section: Introductionmentioning

confidence: 99%

Ultrafast energy transfer with competing channels: Non-equilibrium Förster and Modified Redfield theories

Seibt

Mančal

2017

The Journal of Chemical Physics

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We derive equations of motion for the reduced density matrix of a molecular system which undergoes energy transfer dynamics competing with fast internal conversion channels. Environmental degrees of freedom of such a system have no time to relax to quasi-equilibrium in the electronic excited state of the donor molecule, and thus the conditions of validity of Förster and Modified Redfield theories in their standard formulations do not apply. We derive non-equilibrium versions of the two well-known rate theories and apply them to the case of carotenoid-chlorophyll energy transfer. Although our reduced density matrix approach does not account for the formation of vibronic excitons, it still confirms the important role of the donor ground-state vibrational states in establishing the resonance energy transfer conditions. We show that it is essential to work with a theory valid in strong system-bath interaction regime to obtain correct dependence of the rates on donor-acceptor energy gap.

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Section: Introductionmentioning

confidence: 99%

Ultrafast energy transfer with competing channels: Non-equilibrium Förster and Modified Redfield theories

Seibt

Mančal

2017

The Journal of Chemical Physics

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“…The unique chromophoric nature of chlorophyll and the elegant geometrical arrangement of these pigments in the LHCs of plants and bacteria allow for photon energy to be efficiently captured and funnelled from the environment to reaction centres. This biological light harvesting critically depends on the quantum mechanism through which photon-induced excitations hop between chromophores [13]. An initially excited donor chromophore can convey its electronic energy to an acceptor chromophore via electrodynamic coupling of their transition electric dipole moments owing to the close correspondence, or 'resonance', between their energy levels.…”

Section: Introductionmentioning

confidence: 99%

The feasibility of coherent energy transfer in microtubules

Craddock

Friesen

Mane

et al. 2014

J. R. Soc. Interface.

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It was once purported that biological systems were far too 'warm and wet' to support quantum phenomena mainly owing to thermal effects disrupting quantum coherence. However, recent experimental results and theoretical analyses have shown that thermal energy may assist, rather than disrupt, quantum coherent transport, especially in the 'dry' hydrophobic interiors of biomolecules. Specifically, evidence has been accumulating for the necessary involvement of quantum coherent energy transfer between uniquely arranged chromophores in light harvesting photosynthetic complexes. The 'tubulin' subunit proteins, which comprise microtubules, also possess a distinct architecture of chromophores, namely aromatic amino acids, including tryptophan. The geometry and dipolar properties of these aromatics are similar to those found in photosynthetic units indicating that tubulin may support coherent energy transfer. Tubulin aggregated into microtubule geometric lattices may support such energy transfer, which could be important for biological signalling and communication essential to living processes. Here, we perform a computational investigation of energy transfer between chromophoric amino acids in tubulin via dipole excitations coupled to the surrounding thermal environment. We present the spatial structure and energetic properties of the tryptophan residues in the microtubule constituent protein tubulin. Plausibility arguments for the conditions favouring a quantum mechanism of signal propagation along a microtubule are provided. Overall, we find that coherent energy transfer in tubulin and microtubules is biologically feasible.

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“…Various models addressed the high efficiency of energy transfer in photosynthetic antennae (14)(15)(16)(17)(18)(19) and the mechanisms of charge separation in reaction centers (12,(20)(21)(22). Furthermore, quantum coherence effects, e.g., photon echo, have been observed in a series of interesting photosynthesis experiments (23)(24)(25)(26)(27)(28)(29)(30).…”

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confidence: 99%

Photosynthetic reaction center as a quantum heat engine

Dorfman

Voronine

Mukamel

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

282

339

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Two seemingly unrelated effects attributed to quantum coherence have been reported recently in natural and artificial light-harvesting systems. First, an enhanced solar cell efficiency was predicted and second, population oscillations were measured in photosynthetic antennae excited by sequences of coherent ultrashort laser pulses. Because both systems operate as quantum heat engines (QHEs) that convert the solar photon energy to useful work (electric currents or chemical energy, respectively), the question arises whether coherence could also enhance the photosynthetic yield. Here, we show that both effects arise from the same population-coherence coupling term which is induced by noise, does not require coherent light, and will therefore work for incoherent excitation under natural conditions of solar excitation. Charge separation in light-harvesting complexes occurs in a pair of tightly coupled chlorophylls (the special pair) at the heart of photosynthetic reaction centers of both plants and bacteria. We show the analogy between the energy level schemes of the special pair and of the laser/photocell QHEs, and that both population oscillations and enhanced yield have a common origin and are expected to coexist for typical parameters. We predict an enhanced yield of 27% in a QHE motivated by the reaction center. This suggests nature-mimicking architectures for artificial solar energy devices.photosynthesis | quantum biology | population oscillations | quantum coherence A ccording to the laws of quantum thermodynamics, quantum heat engines (QHEs) convert hot thermal radiation into low-entropy useful work (1, 2). The ultimate efficiency of such QHEs is usually governed by a detailed balance between absorption and emission of the hot pump radiation (3). The laser is an example of a QHE, which can use incoherent pump (heat) radiation to produce highly coherent (low-entropy) light ( Fig. 1 A and B). Moreover, it was demonstrated both theoretically and experimentally that noise-induced quantum coherence (4) can break detailed balance and yield lasers without population inversion (5) and/or with enhanced efficiency (Fig. 1C).Recently it has been shown that quantum coherence can, in principle, enhance the efficiency of a solar cell or a photodetector (6-10). This photocell QHE (Fig. 1D) can be described by the same model as the laser QHE (Fig. 1E) and obeys similar detailed balance physics. To use the broad solar spectrum and eliminate phonon loss, we separate solar flux into narrow frequency intervals and direct it onto a cell array where each of the cells has been prepared to have its band gap equal to that photon energy (7). In particular, Shockley and Queisser (11) invoked detailed balance to show that the open-circuit voltage of a photocell is related to the energy input of a "hot" monochromatic thermal light by the Carnot factor. However, just as in the case of the laser, we can, in principle, break detailed balance by inducing coherence (Fig. 1F), which can enhance the photocell efficiency (9, 10).Other recent p...

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How Quantum Coherence Assists Photosynthetic Light-Harvesting

Cited by 180 publications

References 67 publications

Ultrafast energy transfer with competing channels: Non-equilibrium Förster and Modified Redfield theories

Ultrafast energy transfer with competing channels: Non-equilibrium Förster and Modified Redfield theories

The feasibility of coherent energy transfer in microtubules

Photosynthetic reaction center as a quantum heat engine

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