Dead vs Alive Quantum Biology: Magnetoreception Enabled via Non-Markovianity

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The emerging field of quantum biology suggests that nature may utilise non-trivial quantum effects to realize a classically unattainable advantage in the complex systems of life.The avian compass, which allows migratory birds to navigate over vast distances, is thought to be a prime example where quantum effects underpin biology. Evidence implies that this sense originates from a light-activated chemical reaction taking place in a protein called cryptochrome, located in the bird's eye. The reaction initiates magnetic field sensitive dynamics of spins, an intrinsic quantum property, of electrons and magnetic nuclei in two "radical" molecules. Consequently, the recombination of the radical pair to reform the protein's resting state is thought to acquire magnetic field sensitivity. However, many open questions remain to be solved to understand the exquisite, possibly quantum enhanced, sensitivity of nature and unlock its design principles.The majority of current models of the avian compass treat the dynamics of the cryptochrome in isolation. However, recent studies show that the response of an isolated cryptochrome to weak magnetic fields is likely insufficient to support bird navigation. We suggest that the key to this 'interaction strength gap' can be found in the protein's environment. Specifically, we propose that the oft-neglected openness of the spin system to the strongly coupled structured environment can provide an essential sensitivity boost through driving and noise contributions, caused by the physiological motion of the protein at timescales relevant to magnetoreception, and mediated via inter-radical interactions. This enhancement principle contrasts with common efforts to reduce environment interaction, which is seen as detrimental, in most instances of man-made quantum technology. However, for magnetoreception, our preliminary results suggest that, counterintuitively, the environment itself may be utilized to reinforce and revive quantum dynamics - in particular if the interaction with the environment has a finite memory time (non-Markovianity).We will develop new theory and computationally tractable approaches to unlock the potential of non-Markovian spin dynamics driven by environmental coupling, and to systematically assess the large complex systems of radical-pairs of biology. We will employ wave-function-based methodology in tandem with high-performance and GPU computing techniques to simulate a never before accessible regime that will elucidate non-Markovian enhanced magnetic field sensitivity for realistic systems. Our efforts will culminate in a general, user-friendly software package enabling complex spin dynamics simulations for the scientific community. Our derived insight will supersede current theoretical studies that are oversimplified and resolve the dilemma that current experiments on cryptochrome outside of its biological setting predict inadequate magnetic field sensitivity, thereby opening a new paradigm for biological magnetosensitivity.This interdisciplinary research program will not only invite a "live" treatment of quantum biology by highlighting a functional role of the living system environment, but also provide essential understanding of spin dynamics ubiquitous in chemistry. Several of these potentially magnetic field sensitive chemical reactions could have implications in biology and health (e.g. neurogenesis, lipid peroxidation), motivating a reassessment of exposure guidelines, and generating tools to control reactions in novel medical treatments. Furthermore, by learning from nature and improving upon it, design principles may be found for condensed phase technology manipulating quantum effects, such as quantum sensors that utilize noise as a resource. This will be addressed in the present research project by developing non-Markovian open quantum system treatments of radical reactions accounting for radical motion and complexity, facilitated by advanced numerical approaches.