Researchers at Rice University have made a meaningful advance within the simulation of molecular electron transfer — a fundamental process underpinning countless physical, chemical and biological processes. The study, published in Science Advances, details using a trapped-ion quantum simulator to model electron transfer dynamics with unprecedented tunability, unlocking recent opportunities for scientific exploration in fields starting from molecular electronics to photosynthesis.
Electron transfer, critical to processes resembling cellular respiration and energy harvesting in plants, has long posed challenges to scientists resulting from the complex quantum interactions involved. Current computational techniques often fall in need of capturing the total scope of those processes. The multidisciplinary team at Rice, including physicists, chemists and biologists, addressed these challenges by making a programmable quantum system able to independently controlling the important thing aspects in electron transfer: donor-acceptor energy gaps, electronic and vibronic couplings and environmental dissipation.
Using an ion crystal trapped in a vacuum system and manipulated by laser light, the researchers demonstrated the flexibility to simulate real-time spin dynamics and measure transfer rates across a variety of conditions. The findings not only validate key theories of quantum mechanics but additionally pave the way in which for novel insights into light-harvesting systems and molecular devices.
“That is the primary time that this sort of model was simulated on a physical device while including the role of the environment and even tailoring it in a controlled way,” said lead researcher Guido Pagano, assistant professor of physics and astronomy. “It represents a big step forward in our ability to make use of quantum simulators to analyze models and regimes which can be relevant for chemistry and biology. The hope is that by harnessing the facility of quantum simulation, we’ll eventually give you the option to explore scenarios which can be currently inaccessible to classical computational methods.”
The team achieved a big milestone by successfully replicating a normal model of molecular electron transfer using a programmable quantum platform. Through the precise engineering of tunable dissipation, the researchers explored each adiabatic and nonadiabatic regimes of electron transfer, demonstrating how these quantum effects operate under various conditions. Moreover, their simulations identified optimal conditions for electron transfer, which parallel the energy transport mechanisms observed in natural photosynthetic systems.
“Our work is driven by the query: Can quantum hardware be used to directly simulate chemical dynamics?” Pagano said. “Specifically, can we incorporate environmental effects into these simulations as they play an important role in processes essential to life resembling photosynthesis and electron transfer in biomolecules? Addressing this query is important as the flexibility to directly simulate electron transfer in biomolecules could provide invaluable insights for designing recent light-harvesting materials.”
The implications for practical applications are far-reaching. Understanding electron transfer processes at this level could lead on to breakthroughs in renewable energy technologies, molecular electronics and even the event of recent materials for quantum computing.
“This experiment is a promising first step to achieve a deeper understanding of how quantum effects influence energy transport, particularly in biological systems like photosynthetic complexes,” said Jose N. Onuchic, study co-author, the Harry C. and Olga K. Wiess Chair of Physics and professor of physics and astronomy, chemistry and biosciences. “The insights we gain in the sort of experiment could encourage the design of more efficient light-harvesting materials.”
Peter G. Wolynes, study co-author, the D.R. Bullard-Welch Foundation Professor of Science and professor of chemistry, biosciences and physics and astronomy, emphasized the broader significance of the findings: “This research bridges the gap between theoretical predictions and experimental verification, offering an exquisitely tunable framework for exploring quantum processes in complex systems.”
The team plans to increase its simulations to incorporate more complex molecular systems resembling those involved in photosynthesis and DNA charge transport. The researchers also hope to analyze the role of quantum coherence and delocalization in energy transfer, leveraging the unique capabilities of their quantum platform.
“That is just the start,” said Han Pu, co-lead writer of the study and professor of physics and astronomy. “We’re excited to explore how this technology may help unravel the quantum mysteries of life and beyond.”
The study’s other co-authors include graduate students Visal So, Midhuna Duraisamy Suganthi, Abhishek Menon, Mingjian Zhu and research scientist Roman Zhuravel.
This research was made possible due to the Welch Foundation Award C-2154, the Office of Naval Research Young Investigator Program (No. N00014-22-1-2282), a National Science Foundation CAREER Award (No. PHY-2144910), the Army Research Office (W911NF22C0012), the Office of Naval Research (No. N00014-23-1-2665), the NSF (PHY-2207283, PHY-2019745 and PHY-2210291) and the D. R. Bullard-Welch Chair at Rice (No. C0016). The authors acknowledge that this material is predicated upon work supported by the usDepartment of Energy, Office of Science, Office of Nuclear Physics under the Early Profession Award No. DE-SC0023806. The isotopes utilized in this research were supplied by the U.S. Department of Energy Isotope Program managed by the Office of Isotope R&D and Production.
