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.
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.
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.
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.
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.
Open quantum system approaches are widely used in the description of physical, chemical and biological systems. A famous example is electronic excitation transfer in the initial stage of photosynthesis, where harvested energy is transferred with remarkably high efficiency to a reaction center. This transport is affected by the motion of a structured vibrational environment, which makes simulations on a classical computer very demanding. Here we propose an analog quantum simulator of complex open system dynamics with a precisely engineered quantum environment. Our setup is based on superconducting circuits, a well established technology. As an example, we demonstrate that it is feasible to simulate exciton transport in the Fenna–Matthews–Olson photosynthetic complex. Our approach allows for a controllable single-molecule simulation and the investigation of energy transfer pathways as well as non-Markovian noise-correlation effects.
Photosynthesis is an important and complex physical process in nature, whose comprehensive understanding would have many relevant industrial applications, for instance in the field of energy production. In this paper we propose a quantum algorithm for the simulation of the excitonic transport of energy, occurring in the first stage of the process of photosynthesis. The algorithm takes in account the quantum and environmental effects (pure-dephasing), influencing the quantum transport. We performed quantum simulations of such phenomena, for a proof of concept scenario, in an actual quantum computer the IBM Q, of 5 qubits. We validate the results with the Haken-Str\"obl model and discuss the influence of environmental parameters on the efficiency of the energy transport.