Dissipative Exciton Dynamics in Light-Harvesting Complexes

Schröter, Marco

doi:10.1007/978-3-658-09282-5

Cited by 7 publications

(12 citation statements)

References 68 publications

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“…The nuclear degrees of freedom are modelled as a discrete primary harmonic bath, which is in turn coupled to a secondary continuous thermal bath consisting of solvent degrees of freedom and any other residual degrees. 36 It is also assumed that the excitons are not directly coupled to the secondary bath.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Local Phonon Environment as a Design Element for Long-lived Excitonic Coherence: Dithia-anthracenophane Revisited

Lal

Ajith

Sebastian

et al. 2022

Preprint

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Excitonic energy transfer in light harvesting complexes, the primary process of photosynthesis, operates with near-unity efficiency. Experimental and theoretical studies suggest that quantum mechanical wave-like motion of excitons in the pigment-protein complex may be responsible for this quantum efficiency. Observed coherent exciton dynamics can be modelled completely only if we consider the interaction of the exciton with its complex environment. While it is known that the relative orientation of the chromophore units and reorganisation energy are important design elements, the role of a structured phonon environment is often not considered. The purpose of this study is to investigate the role of a structured immediate phonon environment in determining the exciton dynamics and the possibility of using it as an optimal design element. Through the case study of dithia-anthracenophane, a bichromophore using the Hierarchical Equations Of Motion formalism, we show that the experimentally observed coherent exciton dynamics can be reproduced only by considering the actual structure of the phonon environment. While the slow dephasing of quantum coherence in dithia-anthracenophane can be attributed to strong vibronic coupling to high-frequency modes, vibronic quenching is the source of long oscillation periods in population transfer. This study sheds light on the crucial role of the structure of the immediate phonon environment in determining the exciton dynamics. We conclude by proposing some design principles for sustaining long-lived coherence in molecular systems.

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Section: Methodsmentioning

confidence: 99%

“…By construction, the zeroth tier ADO, σ ⃗ 0 (t) := ρ(t), is the reduced system density operator. With the MBO model for the system-bath interaction, bath correlation functions can be expanded as a sum of exponentials, 36,38 thus facilitating the use of Eq.4 to solve the exciton dynamics.…”

Section: Methodsmentioning

confidence: 99%

Local Phonon Environment as a Design Element for Long-lived Excitonic Coherence: Dithia-anthracenophane Revisited

Lal

Ajith

Sebastian

et al. 2022

Preprint

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show abstract

“…In order to derive a HEOM version based on the Chebyshev decomposition, we start, in analogy to the derivation of the exponential HEOM 52 with the time evolution of the reduced density matrix, ρ S (t), obtained by applying the time evolution operator to the density matrix at t 0 ,…”

Section: Chebyshev Expansion Applied To Heommentioning

confidence: 99%

Chebyshev hierarchical equations of motion for systems with arbitrary spectral densities and temperatures

Rahman

Kleinekathöfer

2019

The Journal of Chemical Physics

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The time evolution in open quantum systems, such as a molecular aggregate in contact with a thermal bath, still poses a complex and challenging problem. The influence of the thermal noise can be treated using a plethora of schemes, several of which decompose the corresponding correlation functions in terms of weighted sums of exponential functions. One such scheme is based on the hierarchical equations of motion (HEOM), which is built using only certain forms of bath correlation functions. In the case where the environment is described by a complex spectral density or is at a very low temperature, approaches utilizing the exponential decomposition become very inefficient. Here we utilize an alternative decomposition scheme for the bath correlation function based on Chebyshev polynomials and Bessel functions to derive a hierarchical equations of motion approach up to an arbitrary order in the environmental coupling. These hierarchical equations are similar in structure to the popular exponential HEOM scheme, but are formulated using the derivatives of the Bessel functions. The proposed scheme is tested up to the fourth order in perturbation theory for a two-level system and compared to benchmark calculations for the case of zero-temperature quantum Ohmic and super-Ohmic noise. Furthermore, the benefits and shortcomings of the present Chebyshev-based hierarchical equations are discussed.

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“…Modeling physical phenomena via the coupling of twolevel systems (qubits) to quantized harmonic oscillators has historically been of great interest in diverse fields ranging from quantum optics [1][2][3][4] and solid-state physics [5,6] to quantum biology [7][8][9][10]. This approach has become frequent in modern physics since fully quantummechanical descriptions may reveal phenomena not covered by classical or semiclassical approaches.…”

Section: Introductionmentioning

confidence: 99%

Coupled modes locally interacting with qubits: Critical assessment of the rotating-wave approximation

2017

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The interaction of qubits with quantized modes of electromagnetic fields has been largely addressed in the quantum optics literature under the rotating wave approximation (RWA), where rapid oscillating terms in the qubit-mode interaction picture Hamiltonian can be neglected. At the same time, it is generally accepted that provided the interaction is sufficiently strong or for long times, the RWA tends to describe physical phenomena incorrectly. In this work, we extend the investigation of the validity of the RWA to a more involved setup where two qubit-mode subsystems are brought to interaction through their harmonic coordinates. Our treatment is all analytic thanks to a sequence of carefully chosen unitary transformations which allows us to diagonlize the Hamiltonian within and without the RWA. By also considering qubit dephasing, we find that the purity of the two-qubit state presents non-Markovian features which become more pronounced as the coupling between the modes gets stronger and the RWA loses its validity. In the same regime, there occurs fast generation of entanglement between the qubits which is also not correctly described under the RWA. The setup and results presented here clearly show the limitations of the RWA in a scenario amenable to exact description and free from numerical uncertainties. Consequently, it may be of interest for the community working with cavity or circuit quantum electrodynamic systems in the strong coupling regime.

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Dissipative Exciton Dynamics in Light-Harvesting Complexes

Cited by 7 publications

References 68 publications

Local Phonon Environment as a Design Element for Long-lived Excitonic Coherence: Dithia-anthracenophane Revisited

Local Phonon Environment as a Design Element for Long-lived Excitonic Coherence: Dithia-anthracenophane Revisited

Chebyshev hierarchical equations of motion for systems with arbitrary spectral densities and temperatures

Coupled modes locally interacting with qubits: Critical assessment of the rotating-wave approximation

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