Day 1: Quantum Bio-Photonics Incubator
Maria Solyanik, The George Washington University
The Quantum Bio-Photonics Incubator launched this morning at OSA Headquarters, Washington, DC. A versatile representation of chemists, biologists, and physicists, from Berkeley, Cambridge, Oxford, University of Sydney, and many other places, have been united under one roof to showcase the newest trends in the still maturing field of bio-photonics and quantum chemistry. The organizers' goal has been to foster a friendly environment for open discussions and exchange of best practices in this "very unusual group of people" with different backgrounds, but with a common goal to understand fundamental quantum mechanisms in biological materials. Various communities around the world seem to share their excitement.
The area of quantum bio-photonics has met with some controversy in the scientific community. This seems to come from the fact that the object of this emerging field of study is neither purely quantum nor semi-classical. The core idea of the field is to integrate quantum mechanical rigorousness into the general "messiness" of interactions and correlation effects in biological structures. Host Alexandra Olaya-Castro, University College London, UK, points out that "we need a paradigm shift". Rather than trying to answer specific questions, this Incubator is working towards a common understanding of quantum bio-photonics and hopes to formulate a way to ask meaningful questions. Hopefully, novel ideas and trends that will be born during this meeting will accelerate the paradigm shift and contribute in building a strong theoretical, experimental and technological background for quantum bio-photonics.
Theoretical efforts of the last few decades have yielded results that appear to be very hard to address experimentally. Fundamental questions such as "can one show experimentally that an incoherently excited system evolves quantum mechanically?" or "what are the differences in biological processes in a quantum versus classical description?" appear to pose non-trivial challenges, as was mentioned in the talk by Graham Fleming, University of California, Berkeley, US. Modern experiments provide access to bulk characteristics of biological systems, such as energy transfer efficiency, electron transfer rates, and spectroscopic properties, to name a few. In contrast, many theories are based on the fundamental principles controlling the evolution of ensembles of single states. One needs to work with a reduced amount of disorder in systems, meaning that a certain amount stability in energy levels, correlation, and collective excitation modes within the biological complexes are required. This leads to the conclusion that a new generation of experiments are needed to test the nature of quantum-biological processes and properly set up the axiomatics of the corresponding theoretical tools. In this realm, some experimental techniques that were discussed include fluorescence and light scattering experiments in microscopic biological samples with the use of nano-antenna proteins (Niek van Hulst, ICFO, Spain); precise single-DNA strand structure control and manipulation (Gabriela Schlau-Cohen, MIT, US); and the study of electron transport in single-molecule transistors (Jan Mol, Queen Mary University, UK).
Graham Fleming, University of California, Berkely kicks things off with a spectroscopist's perspective of opportunities and questions for quantum bio-photonics.
To link experimental and theoretical observables, one considers large-scale motion and looks for functions of temporal and spatial evolution, says Alex Chin, Institut des NanoScience de Paris, France. Along this line, he emphasized such collective effects as soliton formation, preservation of relative displacements, and the electronic structure of proteins in biological ensembles. Susana Huelga, Ulm University, Germany, developed the idea of describing the non-Markovian effects in such systems as a noise-assisted process. Her theoretical approach, based on Lindblad master equations, allows a description of the dynamics in biological environments across a broad whole temperature regime. She also expanded her study to modular arrays for modeling the dynamics of photosynthetic membranes. Ahsan Nazir, University of Manchester, UK, introduced an original theoretical approach that incorporated strong thermodynamic coupling into the standard equations for vibrational dynamics.
Some speakers presented promising applications and novel experimental techniques such as harvesting vibration energy from waste heat, using bright, squeezed vacuum states for non-linear response studies, and creating biological quantum networks and sensors using polarization entangled photons in biological macromolecules. Elisabeth Romero, ICIQ, Spain, foresees great progress in the production of solar fuels, based on her spectroscopic study of coherence effects in chromophore-protein assemblies. She emphasized the strong possibility of using such a system for recreating the principles of photosynthesis in the next decade.
In her welcome, Liz Rogan, OSA CEO stated how "Science ecosystem is global." This globalization was clearly demonstrated in the discussion sessions throughout the day. Disputes as to the definitions of coherence, truly quantum processes and the role of correlations in quantum bio-photonics created a rewarding atmosphere for participants to connect and develop a phenomenological framework for linking experiment, theory and available technologies. There are a lot of new ideas to discuss and even more question to answer: "How important is entanglement versus temporal/spectral correlation for quantum biophotonics?" (credit to Graham Fleming), "What is the place of quantum mechanics in the context of coherence and delocalization separation?" (credit to Niek van Hulst), and many more. After a long and fruitful first day, the Quantum Bio-Photonics Incubator participants have made great connections and communicated ideas for the next generation of experiments. We are all looking forward to day two.
Ted Goodson, University of Michigan, discusses the two photon effects in molecules with quantum light.
