Abstract
Exploring unknown quantum systems is an experimental challenge. Recent proposals exploring quantum gravity have suggested circumventing this problem by considering the unknown system as a mediator between two known systems. If such a mediation can locally generate entanglement in the known systems, then the mediator must be non-classical.
The same approach may be applicable to other systems, in particular the brain, where speculations about quantum operations in consciousness and cognition have a long history. Translated to the brain, the mediator is then an unknown brain function. For the quantum systems, we could use proton spins of bulk water, which most likely interfere with the any brain function. Entanglement in these spins can be witnessed with multiple quantum coherence (MQC). We based our witness protocol on zero quantum coherence (ZQC) whereby potential signals from local properties were minimised.
For short repetitive periods, we found ZQC signals in large parts of the brain, whereby the temporal appearance resembled heartbeat-evoked potentials (HEPs). Similar to HEPs, we also found that the ZQC signal depended on conscious awareness. Consciousness-related signals have, to our knowledge, not yet been reported in NMR. Remarkably, we could exclude local properties as contrast mechanism because (a) the ZQC signals had no correlates known in conventional MRI, and (b) the ZQC signals only appeared if the local properties of the magnetisation, which are complementary to non-local properties, were reduced. Our findings suggest that we may have witnessed entanglement mediated by consciousness-related brain functions. Those brain functions must then operate non-classically, which would mean that consciousness is non-classical.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
We extended the introduction and discussion substantially.