Is the human brain a quantum computer Scientists prove brain function is quantum
An experimental team at Trinity College Dublin, Ireland, believes that our brains can use quantum computing: to prove the latest hypothesis about quantum gravity, scientists have applied it to the brain, conducting a series of experiments targeting quantum entanglement mediated by brain functions related to consciousness and cognition.
The related results were published on October 7 in the journal Physics Letters under the title "Experimental indicators of non-classical brain function" [1].
01The brain is non-classical: the quantum of brain function
Quantum mechanisms play a role in the sensory systems that provide information to the brain. For example, in magnetic reception, only quantum mechanical effects can explain its sensitivity. In addition to these sensory inputs, more complex brain functions depend on the presence of specific nuclear spins: nuclear spins can affect chemical reactions in the same way as electron spins, which then lead to macroscopic results common in physiology.
Recently, proposals on quantum gravity [2] have shown that unknown systems can mediate the entanglement between two known quantum systems if the medium itself is non-classical. This approach may be applicable to the brain: if such a brain medium exists, then entanglement is likely to play an important role in the brain. The proton spin of most water is likely to interfere with brain function and can be observed as a known quantum system: if an unknown medium exists, then the multiple quantum coherence (MQC) based nuclear magnetic resonance spectroscopy (NMR) method can act as an entanglement witness.
02Electrophysiological brain waves, witnessing quantum entanglement
The experimental team studied the brains of 40 subjects (18 to 46 years old) using a Tesla-class whole-body MRI scanner (Philips) and recorded relevant data; all participants were asked to remain awake during the imaging protocol.
The aim of this study was to find evidence that brain functions can be entangled in an auxiliary quantum system. Therefore, experiments were performed using a hybrid MRI sequence that could contain both multiple quantum coherence (SQC) and zero quantum coherence (ZQC); it was found that each heartbeat triggered a burst of NMR signals; the signal contrast originated from spin-spin interactions, and therefore, we may have witnessed quantum entanglement.
Patterns observed in participants who reported falling asleep. (A) Waking period. (B) ZQC burst signal decreases with increasing S/N levels when falling asleep.
Thus, it is assumed that there are unknown brain functions that mediate entanglement between auxiliary quantum systems. Experimental tests of such entanglement generated by the brain would be sufficient to demonstrate the non-classical nature of the brain; experimental evidence suggests that the generation of such entanglement is part of physiological and cognitive processes.
03Experimental significance: explains the complexity of how the brain works
Dr. Christian Kerskens, lead physicist at the Trinity College Institute of Neuroscience (TCIN) and co-author of the research article, said [3], "We adapted an idea for an experiment developed to demonstrate the existence of quantum gravity by taking a known quantum system and interacting with an unknown system. If the known system is entangled, then the unknown system must also be a quantum system. It circumvents the difficulty of finding a measurement device for something we know nothing about."
"In our experiments, we use the proton rotation of 'brain water' (brain water) as the known system. 'Brain water' accumulates naturally in our brain as a fluid, and proton spin can be measured with MRI (magnetic resonance imaging). The entangled spins are then sought by using a specific MRI design. We found that the MRI signal is similar to a heartbeat evoked potential, a form of EEG signal."
Dr. Kerskens added, "If entanglement is the only possible explanation here, then this would imply that brain processes must interact with nuclear spins to mediate entanglement between nuclear spins. Therefore, we can infer that these brain functions must be quantized. Because these brain functions are also associated with short-term memory performance and conscious awareness, it is likely that those quantum processes are an important part of our cognitive and conscious brain functions."
"Quantum brain processes could explain why we can still outperform supercomputers when it comes to unforeseen situations, decision making or learning new things. Our experiments, located just 50 meters from the lecture hall where Schrödinger delivered his famous ideas about life, may reveal the mysteries of biology and the mechanisms at work in consciousness that are much harder for science to grasp."
Reference links:
[1]https://iopscience.iop.org/article/10.1088/2399-6528/ac94be
[2]https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.119.240402
[3]https://phys.org/news/2022-10-brains-quantum.html
