Time：14:00-15:30, Thursday, Nov. 16, 2023

Host: Dr. Bing Gu, PI of School of Science, Westlake University

Venue: E10-211, Yungu Campus, Westlake University

Prof. Hongguang Duan,

E-mail: duanhongguang@nbu.edu.cn

Speaker：

Hong-Guang Duan obtained his bachelor’s and master’s degrees from Sichuan Normal University and Ningbo University, respectively. He continued his academic pursuits at the University of Hamburg and the Max Planck Institute in Germany, completing his Ph.D. with the distinction of Summa Cum Laude in 2018. Following his postdoctoral studies at the Max Planck Institute, Hamburg University, and the European XFEL, he was appointed Professor at Ningbo University in 2021 where he assumed a leadership role in the field of optical science within the physics department. Prof. Duan’s doctoral research focused on studying the ultrafast energy transfer and quantum coherence in photosynthetic systems. He is known by his outstanding contributions to the field of biomolecular light harvesting and excitation energy transfer, where he combines excellent experimental skills, with the most advanced theoretical description of his experimental findings.

Currently, his research focuses on employing ultrafast spectroscopy and electron diffraction techniques to unravel the dynamics of wave packets and associated structural transformations in various materials.

Abstract:

The very process of funneling the absorbed photon energy within the chlorophyll antennae system of photosynthetic systems was a critical evolutionary turning point in living systems. It is one of the primal events leading to living systems and occurs on ultrafast times scales approaching the known decoherence time for optically induced coherences/excitation. If there was a biological function where pure quantum effects could be manifest, one would expect it to be observable in the energy transport process in photosynthetic systems – the primal step involved in capturing solar energy for powering living systems. If nature could achieve this exotic quantum state for a design purpose, surely quantum computers, quantum information could be radically transformed if we only understood how nature optimized the system-bath coupling to evade quantum decoherence. We have studied the ultrafast energy transfer in Fenna-Matthews-Olson (FMO) complex and other photosynthetic complexes by employing two-dimensional electronic spectroscopy [1, 2]. With the collaborators, we uncovered the timescales of energy transfer and decay of electronic quantum coherences at different temperatures in the FMO complex. We disentangled the long-lived vibrational coherence from the electronic coherence based on advanced data analysis techniques. We also revealed the lifetime of electronic coherences of pigments involved in strong or weak excitonic interactions. This work provides a guideline for the study of coherent energy transfer in photosynthetic systems and suggests that nature does not use electronic coherence since it is too fragile against the dissipation. In contrast, nature employs dissipation to form effective channels for the ultrafast energy transfer in antenna protein complexes [3, 4, 5].

References:

[1] H. -G. Duan, et al. Quantum coherent energy transport in the Fenna–Matthews–Olson complex at low temperature. Proc. Natl. Acad. Sci. (USA) 119, e2212630119 (2022).

[2] A. Jha, et al. Unraveling Quantum Coherences Mediating Primary Charge Transfer Processes in Photosystem II Reaction Center. Submitted, arxiv.org/abs/2307.12805v1

[3] H. -G. Duan, et al. Nature does not rely on long-lived electronic quantum coherence for photosynthetic energy transfer. Proc. Natl. Acad. Sci. (USA) 114, 8493 (2017).

[4] J. S. Cao, et al. Quantum biology revisited. Science Advances 6, eaaz4888 (2020).

[5] H. -G. Duan, et al. Does electronic coherence enhance anticorrelated pigment vibrations under realistic conditions? J. Chem. Phys. 151, 114115 (2019).

Contact:

School of Science, Li Huang, Email: huangli10@westlake.edu.cn