Explaining the avian compass through sustained quantum dynamics in driven, open three-radical systems
Lead Research Organisation:
UNIVERSITY OF EXETER
Department Name: Physics
Abstract
In the past 25 years, we have witnessed the emergence of quantum technologies, including quantum computers or simulators, from a scientific dream to reality. Google's claim to have achieved quantum supremacy has spurred the global race toward harnessing the quantum advantage. The next major advance, enabled by the applications of quantum computers, may become a reality within decades. The breakthrough hinges on one fundamental imperative: the need to sustain quantum superpositions and, crucially, entanglement in noisy environments.
Has nature evolved to exploit quantum phenomena in ways that surpass current technologies? Could truly quantum effects operate in the warm, wet and noisy environment that is characteristic of life? Does this provide a decisive advantage over "classical" processes? Indeed, evidence accumulated over the last four decades does support a conclusion that various organisms employ coherent quantum dynamics to enable magnetoreception: the ability to sense the geomagnetic field.
Yet, it remains to be shown exactly how coherent quantum effects can operate in the warm, wet, and noisy surroundings that are characteristic of biology. Previous studies provided a conceptual model, but failed to rationalize the sustained quantum coherence that is believed to enable this exquisite sensitivity to the magnetic field. We believe this failure is a consequence of an inadequate description of the biological environment, i.e. the openness of the quantum system as it is coupled to the protein motion-a deficit which we here shall overcome. This treatment will explain how living systems could exercise the benefit of a quantum effect to provide a decisive advantage to life. We will do this by focusing, for the first time on systems of radical pairs and three radicals, for which we hope to be able to demonstrate that radical motion can amplify magnetic field effects and sustain quantum dynamics, if the system is driven to a metastable state not accessible in closed-system formulations.
Has nature evolved to exploit quantum phenomena in ways that surpass current technologies? Could truly quantum effects operate in the warm, wet and noisy environment that is characteristic of life? Does this provide a decisive advantage over "classical" processes? Indeed, evidence accumulated over the last four decades does support a conclusion that various organisms employ coherent quantum dynamics to enable magnetoreception: the ability to sense the geomagnetic field.
Yet, it remains to be shown exactly how coherent quantum effects can operate in the warm, wet, and noisy surroundings that are characteristic of biology. Previous studies provided a conceptual model, but failed to rationalize the sustained quantum coherence that is believed to enable this exquisite sensitivity to the magnetic field. We believe this failure is a consequence of an inadequate description of the biological environment, i.e. the openness of the quantum system as it is coupled to the protein motion-a deficit which we here shall overcome. This treatment will explain how living systems could exercise the benefit of a quantum effect to provide a decisive advantage to life. We will do this by focusing, for the first time on systems of radical pairs and three radicals, for which we hope to be able to demonstrate that radical motion can amplify magnetic field effects and sustain quantum dynamics, if the system is driven to a metastable state not accessible in closed-system formulations.
Organisations
Publications
Alvarez P
(2024)
Simulating spin biology using a digital quantum computer: Prospects on a near-term quantum hardware emulator
in APL Quantum
Brokowski T
(2022)
Spin Chemistry Simulation via Hybrid-Quantum Machine Learning
Chowdhury F
(2023)
Quantum Control of Radical Pair Dynamics beyond Time-Local Optimization
Chowdhury F
(2024)
Quantum Control of Radical-Pair Dynamics beyond Time-Local Optimization
in PRX Quantum
Denton M
(2024)
Magnetosensitivity of tightly bound radical pairs in cryptochrome is enabled by the quantum Zeno effect
in Nature Communications
Deviers J
(2022)
Anisotropic magnetic field effects in the re-oxidation of cryptochrome in the presence of scavenger radicals.
in The Journal of chemical physics
Deviers J
(2024)
Avian cryptochrome 4 binds superoxide.
in Computational and structural biotechnology journal
Gerhards L
(2023)
Modeling spin relaxation in complex radical systems using MolSpin.
in Journal of computational chemistry
Grüning G
(2022)
Effects of Dynamical Degrees of Freedom on Magnetic Compass Sensitivity: A Comparison of Plant and Avian Cryptochromes.
in Journal of the American Chemical Society
| Description | The ability of animals to sense the weak Earth's magnetic field (magnetoreception) has long been a mystery. A leading theory, motivated by theoretical and experimental studies, suggests it relies on quantum phenomena taking place in the cryptochrome protein, for example, located in bird's retinae. However, whilst providing the conceptual basis of the mechanism, thus far models have been unable to produce the levels of sensitivity required to agree with ethological observations on magnetic field responses. In this investigation we set out to rationalise how sustained quantum coherence could enable magnetoreception within a radical-based (molecules with an odd number of electrons) compass that relies on the dynamics of quantum spin (an intrinsic angular momentum of electrons and nuclei). Our objective was to go beyond prior idealised studies, that provided a conceptual model yet neglected complexity inherent in biological systems such as interactions between electron spins, and to the many surrounding nuclei and protein. Surprisingly, as it contrasted the existing understanding based on toy models, we found that an often-used measure of coherence of the electronic system alone was not a good system-independent quantifier of compass sensitivity. Instead, we discovered that global coherence, i.e. of the electronic and nuclear system together, strongly correlated with compass sensitivity across different radical systems, thus justifying its rationalisation as a resource to magnetoreception and furthering our fundamental understanding of quantum coherence in complex systems. The results of this study were published in the journal Scientific Reports entitled "Observations about utilitarian coherence in the avian compass" and featured in its top 100 list of publications in Physics of 2022. With respect to the second complexity of biological systems, the protein environment, we hypothesised that it could drive motion of the radicals and in turn amplify magnetic effects, for example, by sustaining quantum spin dynamics. Our work allowed us to confirm this hypothesis and demonstrate that harmonically driven radicals can indeed enhance magnetic field sensitivity and restore it despite detrimental inter-radical interactions. We found this motion can alter the systems energies, thereby freeing it when it becomes trapped in a particular state that inhibits sensitivity, by allowing coherent inter-conversion between states to occur via so called driven non-adiabatic transitions (Landau-Zener-Stückelberg-Majorana transitions), a truly quantum phenomena not described by semiclassical theory. The results of this study, published in the letter "Driven Radical Motion Enhances Cryptochrome Magnetoreception: Toward Live Quantum Sensing" in the Journal of Physical Chemistry Letters, has enabled us to revolutionise established radical-based mechanisms of spin chemistry, thereby paving the path to new avenues of discovery that could provide a route towards resolving the sensitivity gap between quantum theory and ethological observation. |
| Exploitation Route | Concerning the development of the quantum theory of magnetoreception, our work has provided deep insights into the necessity of treating the complexity inherent in biological systems and expanding upon the established mechanism. We anticipate that this will motivate the scientific community to revisit the theory and experiments with this in mind, inspiring new research to be conducted that will further our understanding of quantum dynamics in magnetoreception, spin chemistry, and quantum biology in general. Within our own group this has facilitated a collaboration investigating the limits of precision possible, as system complexity is increased, via quantum information studies. Furthermore, it has enabled us to take our findings forward and develop a new theory that suggests that a strongly coupled structured protein environment can provide an essential sensitivity boost through driving components and noise contributions that may be utilized to reinforce and revive quantum dynamics - in particular if the interaction with the environment has a finite memory time (non-Markovianity). This hypothesis invites a description that suggests the quantum processes within a living system (in vivo) may be bolstered by dynamics not present within "dead" systems, e.g. current in vitro system explorations, and is the central concept of the EPSRC grant "Dead vs Alive Quantum Biology: Magnetoreception Enabled via Non-Markovianity." We anticipate that this will lead to a paradigm shift in quantum biology and help to bridge the gap to the open quantum systems community motivating interdisciplinary collaborative studies and methodology development. Our studies could also encourage a route for the control of quantum phenomena both in biological, therapeutic, and technological applications, by understanding how the enhancing effects we have discovered may be produced and engineered. |
| Sectors | Environment Healthcare Manufacturing including Industrial Biotechology Pharmaceuticals and Medical Biotechnology Other |
| Description | Reported on the potenitial of quantum effects to underpin the putative magnetosensitivity of reactive oxygen species |
| Geographic Reach | Europe |
| Policy Influence Type | Contribution to a national consultation/review |
| Description | Spin biology under optimal quantum control |
| Amount | $611,000 (USD) |
| Funding ID | N62909-21-1-2018 |
| Organisation | ONRG Office of Naval Research Global |
| Sector | Public |
| Country | United States |
| Start | 08/2021 |
| End | 08/2024 |
| Description | The quantum avian compass probed on the single molecule level |
| Amount | £200,889 (GBP) |
| Funding ID | EP/X018822/1 |
| Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
| Sector | Public |
| Country | United Kingdom |
| Start | 11/2022 |
| End | 04/2024 |
| Description | Three, not two, radicals: Revealing the true mechanism of cryptochrome magneto-sensation |
| Amount | £196,000 (GBP) |
| Funding ID | BB/Y51312X/1 |
| Organisation | Biotechnology and Biological Sciences Research Council (BBSRC) |
| Sector | Public |
| Country | United Kingdom |
| Start | 01/2024 |
| End | 12/2024 |
| Title | Superoxide magnetosensitivity |
| Description | We have suggested a hitherto unknown mechanism to explain the cryptic magnetosensitivity of superoxide-containing radical pairs, which has frequently been postulated, but contradicted the convention model, the radical pair model, as a result of too fast spin relaxation. The new model overcomes this conceptual issue by combining the quantum Zeno effect and superoxide-protein interactions that reduce the anions rotational tumbling. The model can rationalize many so far inexplicable observations in the literature and is relevant to the assessment of potential health risks and benefits associated with the exposure to magnetic fields. |
| Type Of Material | Computer model/algorithm |
| Year Produced | 2023 |
| Provided To Others? | Yes |
| Impact | New models and understanding of the effects of exposing biological systems to weak magnetic fields or hypomagnetic fields, which have a potential to revolutionize the use of magnetic fields in medical therapy and are relevant to risk assessment. |
| Description | Collaboration with Manchester, Leicester and NPL on cryptochrome CTT |
| Organisation | National Physical Laboratory |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | We have contributed molecular dynamics simulations in an effort to explain magnetic field effects in D. melanogaster that are surprisingly mediated by the 54 -residue C-terminal appendix of cryptochrome. We build a model that focuses on the binding of free FAD and predicted the effect of specific mutations of the pedide, which were later confirmed in in vitro experiments. |
| Collaborator Contribution | Our partner have discovered the surprising effect of the C-terminal tail. They have extensively studied the phenomenon through in vivo and in vitro asseyes. |
| Impact | WE are in the processes of acquiring funding for a large-scale joint project, whereby the group would contribute the modelling and interpretation part, employing molecular dynamics and spin dynamics calculations. |
| Start Year | 2023 |
| Description | Collaboration with Manchester, Leicester and NPL on cryptochrome CTT |
| Organisation | University of Leicester |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | We have contributed molecular dynamics simulations in an effort to explain magnetic field effects in D. melanogaster that are surprisingly mediated by the 54 -residue C-terminal appendix of cryptochrome. We build a model that focuses on the binding of free FAD and predicted the effect of specific mutations of the pedide, which were later confirmed in in vitro experiments. |
| Collaborator Contribution | Our partner have discovered the surprising effect of the C-terminal tail. They have extensively studied the phenomenon through in vivo and in vitro asseyes. |
| Impact | WE are in the processes of acquiring funding for a large-scale joint project, whereby the group would contribute the modelling and interpretation part, employing molecular dynamics and spin dynamics calculations. |
| Start Year | 2023 |
| Description | Collaboration with Manchester, Leicester and NPL on cryptochrome CTT |
| Organisation | University of Manchester |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | We have contributed molecular dynamics simulations in an effort to explain magnetic field effects in D. melanogaster that are surprisingly mediated by the 54 -residue C-terminal appendix of cryptochrome. We build a model that focuses on the binding of free FAD and predicted the effect of specific mutations of the pedide, which were later confirmed in in vitro experiments. |
| Collaborator Contribution | Our partner have discovered the surprising effect of the C-terminal tail. They have extensively studied the phenomenon through in vivo and in vitro asseyes. |
| Impact | WE are in the processes of acquiring funding for a large-scale joint project, whereby the group would contribute the modelling and interpretation part, employing molecular dynamics and spin dynamics calculations. |
| Start Year | 2023 |
| Description | Collaboration with Prof. Aiello and Banerjee (USLA) |
| Organisation | University of California, Los Angeles (UCLA) |
| Country | United States |
| Sector | Academic/University |
| PI Contribution | We have contributed to this collaboration with spin dynamics calculations, both of radical pair systems, which are at the heart of the "Explaining the avian compass through sustained quantum dynamics in driven, open three-radical systems"-project, and of nuclear spin clusters, i.e. the Posner molecule. |
| Collaborator Contribution | Our partners have contributed ab initio and classical molecular dynamics simulations and DFT calculations. |
| Impact | We have jointly authored a publication in a related field and are currently in the processes of preparing another. The project is multi-disciplinary; it involves the QuBiT Lab and Ab Initio Simulations Lab at the Electrical and Computer Engineering at UCLA and the Living Systems Institute and Department of Physics at the University of Exeter. |
| Start Year | 2021 |
| Title | CUDA-enabled kernes for spin dynamics calculations |
| Description | We have develop a CUDA-enabled kernels for the simulation of magnetic field effects as resulting from the spin dynamics in radical pairs. These programs allows solving the Liouville von-Neumann equation of the spin density operator of radical pairs comprising a large number of hyperfine-coupled nuclear spins on GPUs, thereby providing simulations of larger, more realistic systems than was previously achievable. |
| Type Of Technology | New/Improved Technique/Technology |
| Year Produced | 2021 |
| Impact | These sets of programs are essential for the realization of this research project, as they provide us with the tools necessary to address more realistic spin systems. The kernels have been partly released to the public domain (as supplemental data of a recent publication). We plan to collect the kernels in a toolkit, expand their scope and optimize the underlying numerical methods. We will then release the toolkit subject to an open source license in the near future. |
| Description | British Science Festival 2023 |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | Regional |
| Primary Audience | Public/other audiences |
| Results and Impact | Showcase of Magnetoreception and Quantum Biology at the British Science Festival held at Exeter's city centre: We informed an audience of the general public about Quantum Biology and its relevance to magnetoreception in birds. The exhibition contained a VR-element, allowing participants to immerse themselves in a bird flight and perceiving, from an bird's eye view, visual magnetoreception in the form of visual modulation patterns. We also provided VR-animations of the protein dynamics that underpin magnetoreception on the molecular level. |
| Year(s) Of Engagement Activity | 2023 |
| URL | https://britishsciencefestival.org/programme-2023-revealed/ |
| Description | VR exhibition on quantum navigation and magnetoreception at the Futures festival |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | Regional |
| Primary Audience | Public/other audiences |
| Results and Impact | RCoI presented a 2 day VR exhibition to the public at the Futures festival 09/24 in Exeter on quantum navigation and magnetoreception. |
| Year(s) Of Engagement Activity | 2024 |