From Heat Engines to Green Leaves: An Experimental Physicist’s Perspective on Photosynthesis

Nathan Gabor
UC Riverside
Thursday, October 17, 2019
3:30 pm
RH 101
Photosynthesis is remarkable, achieving near unity light harvesting quantum efficiency in spite of dynamic light conditions, rapidly fluctuating molecular structure, and highly intricate energy transfer pathways. The delicate interplay of quantum effects with molecular mechanisms of energy management have been explored across highly diverse phototrophs, giving unique insight for bio-inspired technologies. However, it remains unknown whether there exists a fundamental organizing principle that gives rise to robust photosynthetic light harvesting.
In this talk, I present a physicist’s perspective on photosynthesis, as laid out by several pioneering quantum physicists including Erwin Schrödinger and George Gamow. I then describe a new paradigm – based on classical noise cancelation – that attempts to describe highly efficient light energy harvesting in complex networks. By understanding the connection between electronic network structure and noise, I show how light harvesting antennae can be finely tuned to maximize power conversion efficiency by passively minimizing excitation noise, thus providing a unified theoretical basis for the experimentally observed wavelength dependence of light absorption in green plants, purple bacteria, and green sulfur bacteria. Our noise-canceling antenna model, which establishes the elementary connection between highly efficient light energy harvesting and energetic fluctuations, promises to have applications across various disciplines ranging from quantum nanoscience and computing to bionanoscience and astrobiology.

Bio: Having established himself as a rising leader in quantum optoelectronics research at Cornell University (PhD Physics 2011) and MIT (Postdoctoral Fellow Physics), Prof. Nathaniel Gabor began his academic career at the University of California Riverside in 2013. Nathaniel’s research focuses on quantum optoelectronic measurements of nanoscale materials and has led to the direct observation of highly efficient electron-hole pair multiplication in carbon nanotubes and the unusual hot carrier transport regime in graphene. He has also established leadership in the design and understanding of advanced energy harvesting and storage technologies, having been recognized with numerous national and international awards. Based on several key discoveries regarding light harvesting in biology, Prof. Gabor was named a Scialog Advanced Energy Storage Fellow by the Research Corporation for Science Advancement, as well as a CIFAR Azrieli Global Scholar within the Canadian Institute for Advanced Research. With successful funding as a NSF Career Award, AFOSR Young Investigator Program (YIP) Award, and Presidential Early Career Award in Science and Engineering (PECASE) recipient, his multi-disciplinary research focus has enabled him to pursue scientific topics ranging from electronic liquids to viper vision.
Javier Sanchez-Yamagishi