Quantum effects might indeed play some role in human cognition. Says Matthew Fisher, a physicist at the University of California, Santa Barbara. He published a paper in the Annals of Physics proposing that the nuclear spins of phosphorus atoms could serve as rudimentary “qubits” in the brain, essentially enabling the brain to function like a quantum computer. Fisher has rephrased the question. Is quantum processing happening in the brain?
To build an operating quantum computer, you need to connect qubits or quantum bits of information in a process called entanglement. But entangled qubits exist in a fragile state. They must be carefully shielded from any noise in the surrounding environment. Just one photon bumping into your qubit is enough to make the entire system “decohere” or make the system’s behavior change, changing the entanglement and wiping out the quantum properties of the system. Maintaining coherence for sufficiently long periods of time in the biology is almost impossible.
Over the past decade growing evidence suggests that certain biological systems might employ quantum mechanics. In photosynthesis, for example, the quantum effects help plants turn sunlight into fuel and migratory birds use a “quantum compass” to use Earth’s magnetic fields for navigation, or the human sense of smell is rooted in quantum entanglement.
The lower slower spin of the quanta, the less the nucleus interacts with electric and magnetic fields, and the less quickly its behavior changes and entanglement is released. Two like substances, except for the speed of their spin have very different effects on behavior. Quantum processes might indeed play a functional role in cognitive processing. The brain would need some mechanism for storing quantum information in qubits for a sufficiently long period of time. A mechanism for entangling multiple qubits, and that entanglement must then have some chemically feasible means of influencing how neurons fire in some way. There must also be some means of transporting quantum information stored in the qubits throughout the brain. Fisher has identified one credible candidate for storing quantum information in the brain: phosphorus atoms, which are the only common biological element other than hydrogen with a spin of one-half, a low number that makes possible longer coherence times. Phosphorus can’t make a stable qubit by itself, but its coherence time can be extended further, according to Fisher, if you bind phosphorus with calcium ions to form clusters.