Quantum Biology: The Field That Should Not Exist

There is a quiet revolution happening at the intersection of physics and biology, and it is rewriting the rules of what we thought possible inside living systems.

For most of the twentieth century, quantum mechanics and biology occupied separate kingdoms. Quantum physics governed the impossibly small — electrons, photons, atoms behaving in ways that defied common sense. Biology governed the warm, wet, chaotic world of cells, proteins, and organisms. The two were not supposed to mix. Quantum effects, physicists insisted, could only survive in carefully controlled laboratory conditions — temperatures near absolute zero, vacuums stripped of all interference. The inside of a living cell, with its 37 degrees Celsius heat, its sloshing water, its billions of molecular collisions per second — this was the last place anyone expected to find quantum mechanics at work.

They were wrong.

The Roots: Schrödinger’s Dangerous Question

The story begins in 1944, when Erwin Schrödinger — one of the founding fathers of quantum mechanics, the man who gave us the wave equation that describes all quantum behavior — published a small, deceptively powerful book called What is Life?

Schrödinger asked a question that no physicist had dared to ask seriously: could the strange laws of quantum mechanics explain the stability and order of biological systems? How does life maintain its exquisite organization in a universe that relentlessly slides toward disorder? He proposed that genetic material must function as an “aperiodic crystal” — a structure that stores information in its molecular arrangement, governed by quantum mechanical principles.

The book landed like a depth charge. James Watson read it as a young student and later wrote: “From the moment I read Schrödinger’s What is Life? I became polarized toward finding out the secret of the gene.” Francis Crick, whose background was in physics, cited the same book as the spark that drew him toward molecular biology. Together, they discovered the double helix of DNA in 1953 — a structure that is, in essence, exactly the aperiodic crystal Schrödinger predicted.

Roger Penrose called it “among the most influential scientific writings of the 20th century.” But here is the irony: after Schrödinger opened the door between quantum physics and biology, the scientific establishment spent the next fifty years trying to close it.

The Great Dismissal

The argument against quantum biology seemed ironclad. Quantum effects depend on coherence — the ability of particles to exist in superposition, to be entangled, to tunnel through barriers. Coherence is fragile. It collapses through a process called decoherence whenever a quantum system interacts with its environment. And biological systems are nothing but environment — water molecules vibrating, ions flowing, proteins folding and unfolding millions of times per second.

The math seemed to prove it. Theoretical calculations suggested that quantum coherence in biological tissue would last no longer than femtoseconds — quadrillionths of a second — far too brief to influence any biological process. The case was closed. Quantum mechanics built the atoms that biology uses, but life itself was a purely classical machine.

Then the experiments arrived.

The Four Pillars of Quantum Biology

Starting in the late 1990s and accelerating through the 2000s, a series of extraordinary discoveries shattered the classical consensus. One by one, researchers found quantum effects operating in living systems — not in spite of the warm, wet chaos, but apparently because of it.

Photosynthesis. In 2007, Graham Fleming and Gregory Engel at the University of California, Berkeley, used ultrafast laser spectroscopy to observe quantum coherence in the Fenna-Matthews-Olson complex of green sulfur bacteria. Energy from captured photons was not hopping randomly from molecule to molecule, as classical theory predicted. It was moving as a quantum wave, simultaneously exploring multiple pathways to find the most efficient route to the reaction center. The efficiency was staggering — near 99.9%. A quantum walk, not a classical random walk, was driving the most fundamental energy conversion process in all of biology.

Bird Navigation. European robins and other migratory birds navigate using Earth’s magnetic field, which is extraordinarily weak — about fifty microtesla, roughly a hundred times weaker than a refrigerator magnet. The mechanism turns out to involve cryptochrome proteins in the bird’s retina that, when struck by blue light, generate pairs of molecules with quantum-entangled electrons. The spin states of these radical pairs are sensitive to the orientation of Earth’s magnetic field, essentially giving the bird a quantum compass built into its eyes. Peter Hore at Oxford and Henrik Mouritsen at the University of Oldenburg have been at the forefront of unraveling this mechanism.

Enzyme Catalysis. Judith Klinman at UC Berkeley and Nigel Scrutton at the University of Manchester demonstrated that enzymes — the molecular machines that catalyze virtually every chemical reaction in your body — routinely use quantum tunneling. Hydrogen atoms do not climb over energy barriers as classical chemistry demands. They tunnel straight through, appearing on the other side as if the barrier did not exist. Since carbon-hydrogen bond breaking occurs in roughly 50% of all biological reactions, quantum tunneling is not a curiosity — it is a central mechanism of biochemistry.

Olfaction. In 1996, biophysicist Luca Turin proposed that our sense of smell might work not by molecular shape alone (the “lock and key” model) but by detecting molecular vibrations through quantum tunneling of electrons. The theory predicted that molecules with identical shapes but different vibrational frequencies should smell different. In 2011, Turin and colleagues showed that fruit flies can distinguish between normal molecules and their deuterium-substituted versions — chemically identical in shape but vibrating at different frequencies. The flies were smelling quantum vibrations.

The Researchers Who Built the Field

Several scientists deserve recognition for bringing quantum biology from the fringe to the frontier.

Johnjoe McFadden and Jim Al-Khalili at the University of Surrey traced the origins of quantum biology back to the 1920s, when Niels Bohr first asked whether atomic theory could solve the mystery of life. Their 2014 book Life on the Edge: The Coming of Age of Quantum Biology became the definitive popular account of the field. They examined nearly a hundred years of pioneering questions about the relationship between quantum physics and living systems.

Vlatko Vedral, a Serbian-born physicist at Oxford, pushed the boundaries further by asking whether quantum entanglement might be present in biological energy and information flow. His book Decoding Reality argued that information — quantum information — is the fundamental fabric of the universe, and that biological systems are sophisticated quantum information processors.

Graham Fleming at Berkeley provided the experimental evidence that changed everything. His group’s 2007 photosynthesis experiment was the shot heard round the world of quantum biology — the first direct proof that quantum coherence plays a functional role in a biological system at physiological conditions.

The Decoherence Paradox: How Life Hacks Quantum Physics

Perhaps the most profound discovery in quantum biology is not that quantum effects exist in living systems, but how they survive there. The answer overturns our assumptions about the relationship between quantum mechanics and noise.

Classical thinking held that environmental noise — thermal fluctuations, molecular collisions, the constant vibration of warm matter — could only destroy quantum effects. But research has revealed something astonishing: biological systems do not merely tolerate noise. They exploit it.

This phenomenon, called noise-assisted quantum transport, was first described theoretically by groups including Masoud Mohseni, Patrick Rebentrost, and Seth Lloyd. They showed that in photosynthetic complexes, a precise balance between quantum coherence and environmental noise produces energy transfer efficiencies higher than either pure quantum or pure classical systems could achieve alone. The noise prevents the quantum wave from getting trapped in dead ends, while the coherence allows it to explore multiple paths simultaneously. Nature engineered neither silence nor chaos, but the perfect conversation between the two.

The implications are staggering. Life has not merely survived the warm, wet conditions that should destroy quantum effects. It has evolved to use those very conditions as a feature, not a bug. The molecular architecture of photosynthetic complexes, of cryptochrome proteins, of enzyme active sites — all appear to be precisely tuned to sustain quantum effects just long enough for biology to extract their advantages.

Why This Changes Everything About Consciousness

If quantum effects operate in photosynthesis, in bird brains, in enzyme catalysis, in olfactory receptors — then the question becomes unavoidable: do quantum effects operate in the human brain?

This is where quantum biology meets the hardest problem in all of science — the problem of consciousness. Roger Penrose and Stuart Hameroff have proposed that quantum computations in microtubules within neurons could be the physical basis of conscious experience. The theory remains controversial, but the discovery of quantum effects throughout biology has shifted the conversation from “impossible” to “let’s look more carefully.”

The deeper point is this: quantum biology reveals that the boundary between the quantum world and the classical world is not where we drew it. For a century, we placed the border at the atomic scale and declared everything larger to be classical. Life erased that border. Proteins maintain quantum coherence. Enzymes exploit quantum tunneling. Birds process quantum entanglement in real time. The living world is not a classical machine that happens to be made of quantum parts. It is a quantum system that has learned to operate at scales we never thought possible.

We are not separate from the quantum world. We are built from it, sustained by it, and — if the most daring hypotheses prove correct — conscious because of it.

What happens to our understanding of ourselves when we accept that the deepest processes of life operate at the boundary where physics meets mystery?