It’s possible that our own human brains are capable of performing advanced quantum computing calculations – and now scientists are conducting a series of detailed experiments to try and find out for sure.
It’s easy to think of computers and brains as similar – both process information, and make decisions, and deal with inputs and outputs. But some scientists think the incredible complexity of the brain can only be explained by quantum mechanics.
In other words, phenomena like quantum entanglement and superposition, all the knotty stuff of quantum physics, are actually regular occurrences inside our brains. Not everyone is so sure, but we might be about to get an answer either way.
“If the question of whether quantum processes take place in the brain is answered in the affirmative, it could revolutionise our understanding and treatment of brain function and human cognition,” says one of the team involved in running these tests, Matt Helgeson from the University of California, Santa Barbara (UCSB).
If you’re new to the world of quantum computing, it builds on the ideas of quantum mechanics – ways of explaining the Universe at the smallest atomic scales, when the rules of classical physics no longer appear to fit.
The most crucial part of quantum computing you need to understand is the way that the regular bits or on/off switches of classical computers – all those 1s and 0s that store data – get replaced by qubits.
Qubits can be both 1s and 0s simultaneously, thanks to the idea of superposition we mentioned earlier: the hypothesis that a quantum object can be in multiple states at once, at least until it gets measured.
All of which means quantum computing has the potential to create vastly more complex processing networks than today’s computers can manage, helping us to tackle some of the hardest problems in science.
But back to the human body. The newly funded research about to get underway will go qubit hunting in the brain – qubits usually need extremely low temperatures to work, but there might be ways around that in our warm and wet organs.
One of the upcoming experiments will try and examine whether qubits could be stored in the nuclear spins at the core of atoms, rather than the electrons surrounding them. Phosphorus atoms in particular, which our bodies are packed with, could act as biochemical qubits.
“Extremely well-isolated nuclear spins can store – and perhaps process – quantum information on human time scales of hours or longer,” says one of the team, Matthew Fisher from UCSB.
Other experiments will look at the potential for decoherence, which happens when the links and dependency between qubits – the idea of quantum entanglement – start to break down. For our brains to be quantum computers, there must be a built-in way that our biological qubits are shielded from decoherence.
Yet another experiment is going to investigate mitochondria, the cell subunits responsible for our metabolism and sending messages around the body. It’s possible that these organelles also play a significant role in qubit entanglement.
In other words, the neurotransmitters and synaptic firing in our brains could be creating quantum coupled networks, just like a quantum computer. Fisher and his team will attempt to emulate this in the lab.
Quantum computing processes could eventually help us explain and understand the brain’s most mysterious functions, like the way we hold on to long-term memories, or where consciousness, emotion, and awareness actually come from.
All of this is very high-level, complicated physics, and there’s no guarantee we’re going to get answers. Even if it’s too soon to say for sure whether the brain is a quantum computer or not though, the planned research should reveal much more about how this most complicated of organs works.
“We will explore neuronal function with state-of-the-art technology from completely new angles and with enormous potential for discovery,” says one of the team, Tobias Fromme from the Technical University of Munich in Germany.