Many living organisms can exploit quantum mechanical effects to gain distinct biological advantages. In plants, photosynthesis uses quantum coherence to achieve near 100% efficiency in energy transfer. With advances in experimental techniques, two-dimensional electronic spectroscopy can reveal dynamic processes such as coherence and coupling within a system, and it plays an important role in studying energy transfer in photosynthesis. On the theory side, methods such as the generalized Bloch-Redfield theory and the hierarchical equations of motion are used to model photosynthetic systems. Quantum simulation, as a high-efficiency and low-complexity approach, has also made progress across various platforms in the study of photosynthesis. In recent years, a series of studies has introduced quantum coherence into artificial systems to enhance energy transfer efficiency, laying the groundwork for the design of coherent devices with efficient energy transport. Birds can use the weak geomagnetic field and spin-dependent chemical reactions to detect direction. Theoretical frameworks for animal navigation include magnetite-based mechanisms, magnetoreceptor genes, and the radical-pair mechanism. Quantum simulations of navigation have also advanced on multiple platforms. Inspired by animal navigation, diverse quantum effects have been applied to improve sensing and to support navigation tasks. This paper presents a comprehensive review of progress on quantum coherence in photosynthesis and avian navigation, along with related theoretical methods, quantum simulation approaches, and research on quantum coherent devices.
Many living organisms can exploit quantum mechanical effects to gain distinct biological advantages. In plants, photosynthesis uses quantum coherence to achieve near 100% efficiency in energy transfer. With advances in experimental techniques, two-dimensional electronic spectroscopy can reveal dynamic processes such as coherence and coupling within a system, and it plays an important role in studying energy transfer in photosynthesis. On the theory side, methods such as the generalized Bloch-Redfield theory and the hierarchical equations of motion are used to model photosynthetic systems. Quantum simulation, as a high-efficiency and low-complexity approach, has also made progress across various platforms in the study of photosynthesis. In recent years, a series of studies has introduced quantum coherence into artificial systems to enhance energy transfer efficiency, laying the groundwork for the design of coherent devices with efficient energy transport. Birds can use the weak geomagnetic field and spin-dependent chemical reactions to detect direction. Theoretical frameworks for animal navigation include magnetite-based mechanisms, magnetoreceptor genes, and the radical-pair mechanism. Quantum simulations of navigation have also advanced on multiple platforms. Inspired by animal navigation, diverse quantum effects have been applied to improve sensing and to support navigation tasks. This paper presents a comprehensive review of progress on quantum coherence in photosynthesis and avian navigation, along with related theoretical methods, quantum simulation approaches, and research on quantum coherent devices.
Many biological phenomena including avian navigation and photosynthesis manifest quantum coherent effects. In avian navigation, the weak geomagnetic field and spin-dependent chemical reactions are utilized for navigation. As one of the most important energy sources on earth, photosynthesis has always been a point of discussion for scientists. The study of energy transmission in photosynthetic systems can support the design or performance optimization of artificial light-harvesting devices. Currently, the quantum coherent effect has been observed in photosynthetic complexes, and the quantum efficiency of energy transmission in photosynthetic complexes is close to 100%. These important findings prompted many experts in different disciplines to use quantum physical methods to explore the physical mechanism behind the energy transmission in photosynthetic systems and the role of the quantum coherent effect in the exciton energy transmission in photosynthetic complexes. It has been proven that energy transfer in pigment-protein complexes is mainly in the form of coherent energy transfer. Moreover, the importance of the quantum coherent effect in energy transmission has been proven. Furthermore, several researchers have used the quantum coherent effect to improve energy transmission in photosynthetic systems and achieved some progress. For open quantum systems, such as photosynthetic systems, many theoretical methods have been proposed to analyze their quantum dynamics. These theoretical methods can be divided into two categories according to whether they can describe the diagonal term of the system density matrix, namely, coherent and incoherent theories. Moreover, the application conditions of these theoretical methods differ according to their established processes. Recently, with the progress in research, several groups have proposed several quantum simulation methods based on different quantum computing systems, including quantum simulation methods based on nuclear magnetic resonance systems, superconducting quantum circuit systems, and ion trap systems, to analyze the phenomena in photosynthetic systems. Compared with the traditional theoretical calculation methods, these quantum simulation methods have higher computational efficiency and lower computational complexity. This paper mainly reviews the progress in research on quantum coherent effects in photosynthesis and the related theoretical calculation and quantum simulation methods.
Abstract The lines separating Biology and Physics have started to blur in recent decades, leading to the emergence of the interdisciplinary field known as quantum Biology. This field looks into the possibility that basic quantum mechanical phenomena such as coherence, entanglement, tunneling, and superposition play crucial roles in biological processes that are beyond the scope of classical Physics. Biology has traditionally worked within the parameters of classical mechanics, presuming that delicate quantum effects cannot endure in the warm, humid, and cacophonous environments of living systems. But new findings in fields like photosynthesis, olfaction, avian magnetoreception, and enzyme catalysis indicate otherwise, suggesting that living things intentionally and possibly advantageously use quantum principles. From the earliest speculative theories to the most recent experimental confirmations, this book chapter methodically examines the evolution of quantum Biology. We investigate how the exceptionally high energy transfer efficiency in photosynthetic complexes particularly in the light-harvesting proteins of green sulfur bacteria and plants is supported by quantum coherence. The remarkable speed of proton transfers and enzymatic reactions during DNA replication is also investigated in relation to quantum tunneling. The chapter explores magnetoreception in migratory birds and suggests models in which sensitivity to Earth's geomagnetic field is made possible by radical pair mechanisms influenced by quantum entanglement. We also discuss the intriguing but controversial idea that quantum vibrations improve the human olfactory system's capacity for discrimination. In addition to examining particular occurrences, this research challenges more general theoretical models that seek to balance quantum mechanics with the decoherence commonly observed in biological settings. Recent developments in quantum information theory, biomimetic quantum technologies, and ultrafast spectroscopy are highlighted as essential instruments advancing empirical research. We also critically evaluate the field's methodological difficulties, the skepticism of overly optimistic interpretations, and the significant philosophical ramifications of acknowledging life as a quantum phenomenon. In conclusion, quantum Biology suggests that quantum effects are not uncommon aberrations but rather are an essential part of life, offering not only a fresh perspective for reinterpreting well-known biological processes but also the potential for a fundamental paradigm shift. Quantum biology has the potential to completely transform biotechnology, medicine, and our comprehension of consciousness and the origin of life as experimental methods advance. This chapter highlights the significance of interdisciplinary cooperation in order to completely comprehend the latest discoveries and possible future paths of quantum Biology, highlighting its revolutionary influence on our comprehension of life at the most basic levels. Key words: Quantum Biology, tunneling, avian magnetoreception, enzyme catalysis
We humans always want to believe that we can overpower nature. However, the reality is that nature outperforms humans in many aspects. Animals' abilities to navigate/orient and photosynthesis are two excellent examples in these aspects. However, the mechanisms underlying them are still unknown. For decades, scientists and researchers have made a lot of efforts to reveal these mysteries in nature. Recently, quantum coherence and entanglement are believed to play a crucial role in such biological systems–avian compass and photosynthesis. Thus, nature might know more tricks to utilize quantum mechanics than humans. Studies on the mechanisms underlying avian compass and photosynthesis are highly able to improve or inspire new technologies in detection of weak magnetic fields and solar cells. In this thesis, the effect of quantum coherence and entanglement in these systems is studied. Based on the studied systems, this thesis falls into two parts: avian compass–radical pair mechanism and photosynthesis–enhancing photocell efficiency via coherence. The radical pair mechanism used to explain the avian compass is studied in the first part. It is demonstrated that Cryptochrome is a suitable candidate of the primary magnetoreceptor, located in birds' eyes. Also, the product yields due to the radical pair reactions are able to act as the direction signal for birds. The long-lived quantum entanglement has presented between the radical pairs. In photosynthesis, quantum coherence has been demonstrated to play an essential role in high energy conversion efficiency. Studies have revealed that the quantum coherence can break the detailed balance, the key factor limiting the efficiency in artificial solar cells. By mimicking photosynthetic complexes, a designed solar cell taking advantage of coherent donors caused by dipole-dipole interactions is able to achieve a higher energy conversion efficiency than the famous Shockley-Queisser limit. Again, more and more evidence has shown that quantum mechanics is able to play a crucial role in biological systems. Quantum coherence and entanglement, as main signatures of quantum mechanics, can be used to explain many astonishing phenomena in nature, such as avian magnetoreception and photosynthesis. Learning from nature can accelerate developments of new technologies.
Ultrafast spectroscopy experiments show that photosynthetic systems can preserve quantum beats in the process of electronic energy transfer between pigments, even at room temperature. But what does this discovery imply for biology - and for quantum mechanics? This dissertation examines photosynthesis through the tools of quantum information science. We evaluate to what extent photosynthesis can be thought of as a type of quantum technology, and consider how we can apply experimental tools widely used for quantum technologies (state tomography and coherent control) to photosynthesis. Throughout, we use the Fenna-Matthews-Olson (FMO) complex of greens sulfur bacteria as a model photosynthetic pigment-protein complex.In Part I, we evaluate two mechanisms for the possible biological relevance of quantum coherent motion. First, we consider the extent to which dynamics in light-harvesting systems exhibit the quantum speedups characteristic of quantum algorithms and quantum walks. Second, we demonstrate a ratchet effect in electronic energy transfer enabled by partially coherent dynamics. To do so, we build a new model of energy transfer between weakly coupled light-harvesting complexes to understand how electronic coherence arises under natural conditions.In Part II, we present proposals for experimental probes of light harvesting dynamics with ultrafast spectroscopy. We show how the signal from pump-probe spectroscopy can be formally inverted to determine the excited state electronic density matrix. Finally, we examine the feasiblity of coherent control experiments on light-harvesting systems, and provide two realistic targets feasible with present-day technology.
Over the ten years that NeuroQuantology has been operating , significant strides have been made in advancing our understanding of quantum processes in the biological world, but despite these advances, many questions remain unanswered, particularly when it comes to NeuroQuantology (NeuroScience + QuantumPhysics) and the hard problem of consciousness, leaving many mysteries to be explored over the next ten years.
Ideas from the Last Decade of Quantum Biology
The last decade has produced some significant work showing how quantum effects can occur in biological systems, with advances in three areas utilizing three of the key ideas from quantum physics having been particularly prominent in the media, although often with a certain amount of controversy:
1. Superposition in Photosynthesis
The superposition of a particle, enabling it to exist in a number of different states or locations simultaneously, is an idea that has been used to study how photosynthesis operates. Photosynthesis is an exceptionally efficient process, and it seems that this efficiency is made possible by the fact that superpositioning and coherence allow photons striking light absorbing molecules such as chlorophyll to try all possible routes through to the reaction center simultaneously, before settling for the optimal path.
2. Entanglement in Magnetoreception
Quantum entanglement is one of the ideas that has been used to help explain how birds manage to navigate over extraordinary distances using the earth's magnetic fields as a guide. It has been suggested that entanglement could be occurring within molecules in the birds' eyes, creating an image of the magnetic field that the birds can align themselves with as they fly. The entanglement is created when light striking the birds' eye splits the molecule into a pair of free radicals, each of which has an intrinsic spin that can be reoriented by the magnetic field, but that remains briefly correlated with the other half of the pair as they drift apart.
3. Tunneling in Smell Perception
The idea that a particle can tunnel or pass through an energy barrier, apparently disappearing on one side and then reappearing on the other, has been applied to the problem of understanding how the sense of smell operates. Traditional theories have depended on the idea that a molecule's shape determines its interaction with the smell receptor and therefore its scent, but there are certain molecules that seem to disprove this theory. An alternative theory based on quantum physics suggests that the smell receptors do not detect the molecule's shape, but rather react to subtle energy changes experienced by electrons that disappear from one side of the receptor, tunnel through the molecule, and then reappear on the other side.
Questions in Quantum Neuroscience for the Next Ten Years
The last decade has also seen some significant advances in our understanding of the brain, from research into how quantum computation might create consciousness through coherence in microtubules, to calls for the emergence of a new field of quantum psychiatry to use our understanding of quantum effects in the brain to help tackle mental illness. The progress in this field was perhaps made most apparent by the bringing together of researchers who have been investigating different aspects of quantum neuroscience at the Quantum Paradigms of Psychopathology symposium , in March 2011. Discussions focused on the manner in which quantum effects might not just be occurring in the healthy brain, but also creating pathological symptoms, including mental illnesses such as depression and schizophrenia. Advances in understanding these processes might not just help to unravel the functioning of the brain, but also provide the greatly needed new methods for the diagnosis and treatment of these conditions that are also driving other efforts to map and understand the brain.
How well these efforts will succeed may depend on how willing we are to integrate different approaches, since mapping the neuronal pathways in the brain might not reveal much about how it functions, particularly when it comes to major questions such as the generation of consciousness and the concept of free will. If the ideas of people like Roger Penrose prove to be correct, consciousness may arise not just from the complex arrangement of neural circuits, but from quantum effects produced in the brain tissue, and free will may only be made possible by the existence of quantum phenomena. Even believers in a more traditional neural explanation of the hard problem may still hold out hope that quantum physics will help provide an explanation for consciousness, since, it may require a quantum computer to simulate biological processes at the level of complexity that is occurring in the brain to produce consciousness. NeuroQuantology (NeuroScience + QuantumPhysics) could prove to be the key to some of the biggest science projects of the next decade.
Melissa Bunting
Abstract Near-unity energy transfer efficiency has been widely observed in natural photosynthetic complexes. This phenomenon has attracted broad interest from different fields, such as physics, biology, chemistry, and material science, as it may offer valuable insights into efficient solar-energy harvesting. Recently, quantum coherent effects have been discovered in photosynthetic light harvesting, and their potential role on energy transfer has seen the heated debate. Here, we perform an experimental quantum simulation of photosynthetic energy transfer using nuclear magnetic resonance (NMR). We show that an N-chromophore photosynthetic complex, with arbitrary structure and bath spectral density, can be effectively simulated by a system with log2N qubits. The computational cost of simulating such a system with a theoretical tool, like the hierarchical equation of motion, which is exponential in N, can be potentially reduced to requiring a just polynomial number of qubits N using NMR quantum simulation. The benefits of performing such quantum simulation in NMR are even greater when the spectral density is complex, as in natural photosynthetic complexes. These findings may shed light on quantum coherence in energy transfer and help to provide design principles for efficient artificial light harvesting.