Research Progress
Quantum Coherence in Light-harvesting Systems and Organic Semiconductors
Speaker:Prof. CAO Jianshu
Department of Chemistry, Massachusetts Institute of Technology
Time:2018-09-27 10:00
Place:Exhibition Hall, Hefei National Laboratory Building


  We discover surprising consequences of the well-known quantum effects such as zero-point Quantum coherence is a key concept in chemical physics and will be discussed in the context of charge mobility/exciton diffusion in organic semiconductors and energy transfer in light-harvesting complexes. I. Coherent quantum transport in disordered systems displays an optimal diffusion constant at an intermediate level of noise and temperature. Detailed calculations indicate the crucial role of localization length in coherent transport and predict charge mobility close to experimental values. Further, we have explored the subtle dependence of the diffusion constant on the dimensionality and shape of the sample and demonstrated the universal scaling of the 1D-2D transition in nanotubes.
  Forster energy transfer theory has been extended to multi-chromophoric (MC) systems by incorporating the correlation between exciton and its environments. This correlation leads to the rotation of the reduced density matrix and is fully counted in two recently-developed methods: numerically exact stochastic path integrals (SPI) and theoretically self-consistent coherent potential approximation (CPA). Application of these methods demonstrates incoherent hopping in FMO and coherent transfer in LH2.

  Jianshu Cao is a professor of chemistry at MIT. He received a Ph. D. in physics from Columbia University in 1993, under the direction of Bruce Berne. After postdoctoral research with Greg Voth at University of Pennsylvania and with late Kent Wilson at UCSD, he jointed the MIT faculty in 1998. He is primarily known for his work on open quantum dynamics and single molecule kinetics. His current research program consists of two major components: (i) the development of theoretical and computational methods to model quantum dynamics in light-harvesting systems, organic semiconductors, and quantum devices, and (ii) the analysis of non-equilibrium chemical kinetics and its implications in biophysical processes.
  Over the last five years, (Jan. 2013-Ja. 2018), his group published a total of 56 papers, including 5 in Physical Review Letters, 1 in PNAS, 5 in JPC Letters, 3 in Scientific Reports, 3 in Nano Letters, and 2 in Nature Communications (collaborations). 20% of these publications are collaborative. In addition, Jianshu Cao is actively involved in the scientific community, attending meetings, organizing conferences, serving on editorial boards, and participating in student/scholar exchange programs.

Organizer:Hefei National Laboratory for Physical Sciences at the Microscale

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