Notes on Engineering Health, April 2025: Notes on Quantum Biology

In the murky realm between subatomic particles and living cells, a new scientific frontier is emerging—quantum biology. Quantum biology seeks to explain how the counterintuitive rules of quantum mechanics may underpin some of life's most fundamental processes.

For decades, conventional wisdom held that quantum effects could only manifest in the carefully controlled environments of physics laboratories—environments kept near absolute zero, isolated from the "warm, wet, and noisy" world of biological systems. The idea that quantum mechanics might be relevant to something as complex as a living organism seemed, to many scientists, implausible at best.

But nature, as it turns out, had other plans:

1/ Consider the European robin, which navigates thousands of miles during migration with remarkable precision. In an article entitled The Quantum Robin, Peter Hore, Professor of Chemistry at Oxford University, makes the case that there is growing evidence for this remarkable ability being dependent on a quantum-mechanical effect. Hore's research has shown that cryptochrome proteins in birds' retinas likely generate pairs of quantum-entangled radicals when struck by blue light, creating a magnetic sensor of extraordinary sensitivity.

2/ The vibration theory of olfaction represents another of quantum biology's most intriguing and controversial frontiers. Proposed by biophysicist Luca Turin, this theory suggests that our sense of smell depends not merely on molecular shape — as the classical “lock and key” models suggest—but on quantum mechanical electron tunneling. According to Turin, when an odorant molecule binds to a receptor in our nose, electrons can tunnel between receptor sites only if the molecule's vibrational frequency provides exactly the right quantum of energy—similar to how a specific musical note causes a tuning fork to resonate. This quantum tunneling event would trigger the receptor to signal the brain, creating our perception of a specific smell. Studies by Turin and others have offered evidence that humans and fruit flies can distinguish between molecules with identical shapes but different vibrational frequencies, particularly when comparing normal compounds to their deuterated counterparts, which have identical shapes but different vibrations due to heavier hydrogen atoms. While still contested by many researchers who favor the shape theory of olfaction, this quantum mechanical model helps explain how humans can distinguish between thousands of odors despite having only about 400 types of olfactory receptors, and why certain structurally different molecules can smell remarkably similar when they share vibrational profiles.

3/ Some researchers explain something as fundamental as photosynthesis, the process that powers most life on Earth, as a quantum biologic phenomenon. When sunlight strikes a leaf, photons are captured by light-harvesting complexes containing chlorophyll molecules arranged in precise geometric patterns. Rather than following a single predetermined path, the excited energy exists in a quantum superposition state, simultaneously exploring multiple routes through the photosynthetic apparatus—a phenomenon called quantum coherence. Researchers like Graham Fleming at Berkeley and Greg Engel at University of Chicago have demonstrated that this quantum effect allows the energy to essentially “sample” all possible pathways at once, finding the most efficient route to the reaction center with near-perfect efficiency. This quantum “wave-like” behavior persists for surprisingly long periods (hundreds of femtoseconds) despite the warm, wet environment of the cell that would typically cause rapid decoherence. Plants appear to have evolved specific protein structures that protect these quantum effects from environmental noise, allowing them to harness quantum mechanics for energy transfer with an efficiency that far exceeds our best human-engineered solar technologies. This quantum advantage may explain how photosynthesis achieves its remarkable 95% efficiency in converting captured photons into chemical energy, despite operating at ambient temperatures where quantum effects would typically be masked by thermal fluctuations.

4/ Quantum tunneling in DNA represents one of the more fascinating aspects of quantum biology, potentially influencing genetics at its most fundamental level. During DNA replication and repair, enzymes must recognize and correct mutations, often involving hydrogen atoms shifting between nucleotide bases. Traditional biochemistry suggests that hydrogen atoms would need to overcome an energy barrier to move between DNA base pairs, but quantum mechanics offers another possibility. Through quantum tunneling, hydrogen atoms can essentially “disappear” on one side of an energy barrier and “reappear” on the other without ever possessing the energy classically required to surmount it—a purely quantum phenomenon. Research by Per-Olov Löwdin and others suggests that this tunneling might facilitate proton transfers responsible for spontaneous mutations, as hydrogen atoms can quantum-mechanically tunnel between different tautomeric forms of DNA bases, potentially creating mismatches during replication. More recently, studies have examined how quantum tunneling might enable DNA damage repair through electron transfers across the double helix. While experimental challenges make definitive proof difficult, theoretical models suggest that quantum tunneling may be responsible for the remarkable efficiency of certain DNA repair mechanisms and could help explain the baseline mutation rate observed in living organisms, providing a quantum foundation for evolutionary processes.


As is evidenced by the slow-moving development of quantum computing, harnessing an understanding of quantum phenomenon for applied purposes is enormously challenging. That being said, here are a few problems that could be materially impacted by the development of quantum technologies:

1/ Drug development: Understanding quantum tunneling in enzyme reactions could revolutionize pharmaceutical design. Enzymes may catalyze biochemical reactions partly through quantum tunneling, where particles pass through energy barriers rather than overcoming them. Quantum-informed drug design could target these processes with unprecedented precision.

2/ Medical imaging: Quantum effects could enable super-resolution imaging beyond classical limitations. Research at the University of Ulm has demonstrated how quantum entanglement can overcome diffraction limits in microscopy.

3/ Biosensors: The atomic length scale of quantum sensors and their coherence properties enable unprecedented spatial resolution and sensitivity.

4/ Photosynthesis Optimization: Understanding quantum coherence in photosynthesis could lead to crops with enhanced efficiency. Gregory Scholes of Princeton University, for example, is seeking to enhance these quantum processes which might lead to significant yield improvements even under suboptimal light conditions.

5/ Artificial Photosynthesis: Quantum-inspired solar technologies could dramatically improve efficiency. Natural photosynthesis achieves nearly 100% quantum efficiency in the initial energy capture stage, partly through quantum coherence effects, thus mimicking these quantum processes could potentially double or triple the efficiency of current photovoltaic technologies.

6/ Quantum Batteries: Quantum batteries have the potential to charge significantly faster and potentially store more energy than traditional batteries by harnessing quantum effects like entanglement and superposition. They could also offer advantages in energy efficiency and integration with other quantum technologies.

The quantum nature of life's fundamental building blocks is hard to ignore. Electrons, protons, chemical bonds, and electronic charges—the very essence of biological systems—all obey quantum mechanical principles. This quantum foundation necessarily shapes the behavior of biomolecular complexes, whose interactions often defy classical explanations and demand quantum biological frameworks. Continued investment in both the basic understanding of the intersection of physics and biology, as well as the application of these understandings is likely to be an important priority for decades to come.

– Geoffrey W. Smith



First Five
First Five is our curated list of articles, studies, and publications for the month.

1/ High blood pressure? Eat more bananas.
“High Na+ intake has been linked to elevations in blood pressure, whereas K+ has the opposite effect. The underlying mechanisms involve complex interactions among renal function, fluid volume, fluid-regulatory hormones, vasculature, cardiac function, and the autonomic nervous system. … [S]imulations of high K+ intake yielded kaliuresis, natriuresis, and a substantial reduction in blood pressure, even when combined with high Na+ intake.” Read more here >

2/ Reduce cancer metastasis? Take an aspirin.
“[W]e show that inhibitors of cyclooxygenase 1 (COX-1), including aspirin, enhance immunity to cancer metastasis by releasing T cells from suppression by platelet-derived thromboxane A2 (TXA2).” Read more here >

3/ Foundation of human intelligence
“A study has demonstrated how neurons in the human brain generate memories and establish narratives. Contrary to previous beliefs, individual neurons represent the concepts we learn, regardless of the context in which we encounter them. This allows humans, unlike other animals, to establish higher and more abstract relationships, which lays the foundation of human intelligence.” Read more here >

4/ Protocols, Not Platforms: A Technological Approach to Free Speech
“Altering the internet's economic and digital infrastructure to promote free speech.” Read more here >

5/ Funding Strategies for Data-Intensive Science
From friend of the firm John Wilbanks: “We are poised for an explosion in scientific discovery through DIS. Across a wide range of scientific disciplines, the cost of data generation is dropping. Data generation now leverages cheap sensors, robotics and automation, which drive smaller, cheaper, and higher throughput methods to make data. At the same time, the cost of data storage and processing also continues to decline. As a result, we can now create datasets of ever increasing size at lower and lower costs, and connect them to larger and larger models built through machine learning. We’re entering a world in which large, well-curated datasets enable us to predict scientific outcomes computationally before we test them empirically. … Without a change in how we organize scientific research itself, we won’t be able to use these developments in data generation and modeling at scale.” Read more here >



Did You Know?
Here we seek to demystify common terms and practices in our work as investors.

Waterfall
In venture capital, a waterfall is a method for distributing investment profits in a structured and tiered manner. It outlines the order in which stakeholders receive their share of returns when an investment is exited. This hierarchical approach ensures fair and organized profit distribution among parties involved in the venture capital fund, aligning their interests. The specifics of the waterfall can vary based on fund agreements and preferences, including elements like preferred returns, hurdles, and carried interest arrangements.

– Haiming Chen & Dylan Henderson

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