Quantum Biology, Quantum Simulation and Quantum Coherent Devices

TL;DR

The paper surveys how quantum coherence manifests in biology, focusing on highly efficient energy transfer in photosynthesis and magnetoreception in migratory birds. It integrates theoretical frameworks (e.g., Förster theory, Modified Redfield, Generalized Bloch-Redfield, HEOM), advanced spectroscopic techniques (2DES and variants), and quantum simulation platforms (NMR, superconducting circuits, trapped ions) to elucidate coherence dynamics. Key findings include evidence that electronic and vibronic coherence, protected by the protein environment, underpins efficient energy transfer, and that radical-pair spin dynamics can explain magnetoreception with high sensitivity under realistic conditions. The review also discusses how quantum simulations inform the design of quantum-coherent devices and energy-harvesting architectures, highlighting pathways toward biomimetic sensors and efficient solar-energy technologies. Overall, the work links natural quantum effects to engineered quantum technologies, outlining concrete design principles and platform-ready methods for exploring and exploiting quantum coherence in biology.

Abstract

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.

Figures (2)

• Figure 1: A quantum machine for efficient light-energy harvesting. The FMO complex, a well-known part of the light-harvesting system in green sulfur bacteria, shows signs of quantum coherent energy transfer. Both experiments and theory have examined how this protein moves energy and how quantum it really is. Work in this area could uncover quantum effects that help boost the efficiency of energy capture in living systems. a, Schematic of the photosynthetic system in green sulfur bacteria, comprising the antenna, the energy-transmitting baseplate, the FMO complexes, and the reaction center, the chlorosome antenna (green discs) contains about 200,000 BChl-c molecules and is an unusually large structure optimized to capture as many photons as possible under the low-light conditions preferred by these bacteria, and sunlight generates an excitation in this antenna that is passed (red arrows) to the reaction center via one of several FMO complexes. b, X-ray diffraction reveals the BChl-a arrangement in an FMO pigment–protein complex. The FMO complex contains eight BChl-a molecules (seven shown) embedded in a protein scaffold (not depicted). The excitation typically arrives from the chlorosome at site 1, then migrates from one BChl to the next, and upon reaching site 3 it can irreversibly transfer to the reaction center to initiate charge separation.LambertNeill2013NP
• Figure 2: The avian quantum compass. The radical pair mechanism for avian magnetoreception accounted for many behavioural observations in several migrating bird species. The main features of the proposed model relied on quantum mechanics, so it may have functioned as a piece of biological quantum hardware. a, A diagram of the radical pair mechanism for magnetoreception that could have been used by European robins and other species. It was proposed to occur within cryptochromes in the retina and proceeded in three steps. First, light drove electron transfer from a donor to an acceptor to create a radical pair. b, c, Second, the singlet and triplet electron spin states interconverted due to external Zeeman and internal hyperfine magnetic couplings. d, Third, singlet and triplet radical pairs recombined into singlet and triplet products, which were biologically detectable. e, The singlet yield as a function of the external field angle $\theta$ in the presence of an oscillatory field. The blue top curve showed the yield for a static geomagnetic field with $B_0 = 47\,\mu\text{T}$, and the red curves showed the singlet yield when a $150\,\text{nT}$ field oscillating at $1.316\,\text{MHz}$ was applied perpendicular to the static field. The sensitivity of the compass was the difference in the yield between $\theta=0$ and $\theta=\pi/2$. A clear change in this sensitivity appeared once $\kappa$, the radical decay rate, reached about $10^{4}\,\text{s}^{-1}$. f, The singlet yield as a function of the magnetic field angle $\theta$ for different noise strengths. The blue curve showed the optimal case without noise with $\kappa=10^{4}\,\text{s}^{-1}$. The red curves showed that a general noise rate $\Gamma>0.1\kappa$ reduced the sensitivity. These results together indicated that the electron spin state required a very long coherence time. LambertNeill2013NPGaugerErikM2011PRL