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

新兴的量子生物学领域表明，大自然可能会利用非平凡的量子效应，在复杂的生命系统中实现经典上无法实现的优势。鸟类指南针允许候鸟跨越遥远的距离，被认为是量子效应支撑生物学的一个典型例子。有证据表明，这种感觉源于鸟眼中一种名为隐色素的蛋白质发生的光激活化学反应。该反应引发了两个“自由基”分子中电子和磁核的自旋磁场敏感动力学，这是一种内在的量子性质。因此，自由基对的重组以改变蛋白质的休眠状态被认为获得了磁场敏感性。然而，要理解大自然精致的、可能是量子增强的敏感性，并解开它的设计原理，还有许多悬而未决的问题需要解决。目前的大多数鸟类罗盘模型都是孤立地处理隐色素的动力学。然而，最近的研究表明，分离的隐色素对弱磁场的反应可能不足以支持鸟类导航。我们认为，这种“相互作用强度差距”的关键在于蛋白质所处的环境。具体地说，我们认为，经常被忽视的自旋系统对强耦合结构环境的开放性可以通过驱动和噪声贡献来提供基本的灵敏度提升，这是由蛋白质在与磁接收相关的时间尺度上的生理运动引起的，并通过自由基间的相互作用来调节。这一增强原理与减少环境相互作用的共同努力形成了对比，在大多数人造量子技术的情况下，环境相互作用被视为有害的。然而，对于磁接收，我们的初步结果表明，与直觉相反，环境本身可能被用来加强和复兴量子动力学--特别是如果与环境的相互作用具有有限的记忆时间(非马尔科夫)。我们将开发新的理论和易于计算的方法来解锁由环境耦合驱动的非马尔可夫自旋动力学的潜力，并系统地评估生物学的自由基对的大型复杂系统。我们将使用基于波函数的方法，结合高性能和GPU计算技术来模拟前所未有的区域，这将阐明现实系统的非马尔科夫增强的磁场敏感度。我们的努力将最终形成一个通用的、用户友好的软件包，使科学界能够进行复杂的自旋动力学模拟。我们得出的见解将取代目前过于简化的理论研究，并解决目前在生物背景外对隐花色素的实验预测磁场敏感性不足的困境，从而打开生物磁敏的新范式。这一跨学科研究计划不仅将通过强调生命系统环境的功能作用来邀请量子生物学的“活”治疗，而且还将提供对化学中普遍存在的自旋动力学的基本理解。其中几个潜在的磁场敏感化学反应可能会对生物学和健康产生影响(例如，神经发生、脂质过氧化)，促使对暴露指南进行重新评估，并产生控制新医疗中反应的工具。此外，通过向自然学习并在其基础上改进，可以找到操纵量子效应的凝聚相技术的设计原则，例如利用噪声作为资源的量子传感器。在目前的研究项目中，这将通过开发非马尔科夫开放量子系统处理自由基反应来解决，并借助先进的数值方法来解决自由基运动和复杂性问题。

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.