Abstract We have recently suggested a proposal to explore non-classicality in the brain, for which we developed an entanglement witness protocol using MRI. The witness protocol intended to find spin interactions which could not be explained by classical interactions, based on intermolecular multiple quantum coherence (iMQC). As for Warren’s comments, we show in more detail that this was indeed the case; our observations were certainly not generated by interactions based on the iMQC model. Further, we discuss some additional details not present in the original paper.
Abstract We have recently suggested a proposal to explore non-classicality in the brain, for which we developed an entanglement witness protocol using MRI. The witness protocol intended to find spin interactions which could not be explained by classical interactions, based on intermolecular multiple quantum coherence (iMQC). As for Warren’s comments, we show in more detail that this was indeed the case; our observations were certainly not generated by interactions based on the iMQC model. Further, we discuss some additional details not present in the original paper.
Recent proposals in quantum gravity have suggested that unknown systems can mediate entanglement between two known quantum systems, if and only if the mediator itself is non-classical. This approach may be applicable to the brain, where speculations about quantum operations in consciousness and cognition have a long history. Proton spins of bulk water, which most likely interfere with any brain function, can act as the known quantum systems. If an unknown mediator exists, then NMR methods based on multiple quantum coherence (MQC) can act as entanglement witness. However, there are doubts that today’s NMR signals can contain quantum correlations in general, and specifically in the brain environment. Here, we used a witness protocol based on zero quantum coherence (ZQC) whereby we minimised the classical signals to circumvent the NMR detection limits for quantum correlation. For short repetitive periods, we found evoked signals in most parts of the brain, whereby the temporal appearance resembled heartbeat-evoked potentials (HEPs). We found that those signals had no correlates with any classical NMR contrast. Similar to HEPs, the evoked signal depended on conscious awareness. Consciousness-related or electrophysiological signals are unknown in NMR. Remarkably, these signals only appeared if the local properties of the magnetisation 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.
In a recent paper, we vindicated a general entanglement-based witness of non-classicality in hybrid quantum systems. Our vindication refutes a counterexample to the witness, proposed by Hall and Reginatto. These authors recently commented further, claiming to expose "a huge number of errors and misconceptions" in it. However, their comment contains no refutation of our arguments, nor does it expose any error or misconception in them. But it does include a number of misconceptions about the witness of non-classicality. Here we respond to those.
We have presented an experimental result, where we show that the predictions of an Event-Based Corpuscular Model (EBCM) from Ref. 2, a model that belongs to a class of non-ergodic models first described by Buonomano, are inconsistent with our measurements. We concluded that traditional quantum mechanics adequately describes our experiment, where pure single photons were used, and that our findings agree with earlier verification experiments by Summhammer, where a poissonian source of heavy particles was used. In their comment, Michielsen et al. disagree with the above conclusions. The central point of their argument is that EBCM predictions would be compatible with the observation, if the Mach–Zehnder interferometer (MZI) under test is modeled as a single system, and not as two independent, non-communicating beam splitters (BS). Unfortunately, the physics of interaction and a quantitative model of communication among the parts of MZI that would make it possible to reduce the model to effectively one memory register are not offered. Furthermore, no modification for a verification experiment that would guarantee the absence of an unspecified interaction is offered. An argument resorting to communication between the MZI parts is not a surprise. It is identical to invoking a locality loophole in Bell inequalities: when one considers communication among the different parts of the experimental apparatus, it is well known that hidden variable models can reproduce the results of Quantum Mechanics (QM). But by invoking an undescribed locality loophole, the EBCM and its verification experiment largely loses its appeal, because it becomes a sub-class of hidden variable theories falsifiable via a locality loophole free Bell test. In this sense, the class of local variable theories with noncommunicating memories per each optical element was by far more interesting and unique, because they provide an independent way for testing. We point out that the argument of Michielsen et al. begs the question by suggesting that more experiments are needed while providing no details on how one may avoid any and all interactions that may lead to replacing the two independent registers in the two beam splitters (as originally proposed in their model) with one collective register. Ultimately, we believe that it is not possible to suggest an experiment, even in principle, that would allow a test similar to that from Ref. 2 with the two beam splitters outside of the light cone, i.e., where one could guarantee that no sub-luminal communication occurs, because the ‘‘message carriers’’ are photons that travel with a luminal speed. Given that this loophole can never be closed, it is really hard to define what ‘‘independent’’ means. In view of this, it is unfortunate that Michielsen et al. do not offer any discussion on how to ensure that optical parts are ‘‘independent’’. Particularly, no details are offered on how to reduce independent BSs to a single system that guarantees that the functionality of the device before and after reduction is consistent with QM. How would that reduction occur in nature? Is this reduction adiabatic or discontinuous? How can one control the transition from a set of non-interacting EBCM elements to a single EBCM element? In other words, where are new registers located, and why are they to be moved from the BS as initially asserted, and how does such a device reproduce laws of QM before, during and after such a drastic transition? We believe that, by invoking a non-formalized locality loophole, Michielsen et al. commend the experimental efforts of Ref. 1, acknowledging that all other aspects of the experiment are flawless. That is, the authors of Ref. 1 conducted a fair experiment, in strict accordance with their initial theoretical proposal, and free of an unintentional bias. In conclusion, the comment does not explain how and why the EBCM model is modified to overcome the Ref. 1 test. Further, it neither clarifies the relevance of the model in its new version nor proposes new tests of it. By invoking a non-formalized locality loophole, the authors implicitly moved their model to a much larger class of local realism models.
We reply to the preceding Comment that attempts to clarify the connection between chaos and entanglement exposed in our previous paper [Phys. Rev. E 83, 016207 (2011)PRESCM1539-375510.1103/PhysRevE.83.016207]. We present additional computations that show the argument exposed in the Comment to explain the entangling power of some regular states is not important in the present case. More fundamentally we argue that the example chosen in the Comment is not the most significant in order to understand why specific regular dynamics can entangle as efficiently as when the corresponding classical dynamics is chaotic.
• Using clinical MRI, researchers observed the first indications of a macroscopic quantum entangled state formed by proton spins of water molecules in the living human brain. • By introducing an entanglement witness technique—originally proposed for quantum gravity research—into neuroscience, the team discovered that entanglement signals of proton spins are surprisingly synchronized with Heartbeat-Evoked Potentials (HEPs). • The study provides strong experimental indications that human consciousness, cognition, and brain computational processes are based on non-classical quantum mechanics, confirming that the entanglement-based signals fade away when the subject falls asleep. [Quantum Biology Society] Whether human brain functions, especially consciousness and cognition, are merely the result of classical electrical and chemical signal exchanges between brain cells, or the result of computations akin to a quantum computer based on quantum mechanical principles, has been one of the hottest debates in modern science. While the dominant argument has been that quantum effects would instantly break down in a macroscopic, hot, and wet environment like the brain, a recent study directly capturing strong indications of macroscopic quantum entanglement in the living human brain is exciting the global scientific community. The paper "Experimental indications of non-classical brain functions," published entirely free of charge in the Journal of Physics Communications, contains these remarkable achievements. A research team led by Christian Matthias Kerskens and David López Pérez from the Trinity College Institute of Neuroscience (TCIN) in Dublin, Ireland, successfully conducted this groundbreaking experiment. ■ Quantum Gravity Research Techniques Open the Door to Neuroscience To detect quantum effects in the macroscopic environment of the brain responsible for cognitive functions, the researchers made an unconventional attempt by applying an entanglement witness protocol—originally proposed for quantum gravity research—to clinical magnetic resonance imaging (MRI) of a living human body. MRI measures the proton spins of bulk water in the brain; the researchers highly saturated the magnetization to minimize classical single quantum coherence (SQC) signals, selectively capturing only the target zero quantum coherence (ZQC) signals. ■ Quantum Entanglement in the Brain Synchronized with the Heartbeat The observation results were astonishing. The network of fluid spins (proton spins of bulk water) inside the brain interacted with each other, showing indications of a specific entangled state, and these entanglement-based signal bursts were surprisingly synchronized with the heartbeat-evoked potentials (HEPs) induced by the subject's heartbeat. These pulsating signals could not be explained by any existing classical MRI contrast techniques. ■ Entanglement Signals Disappear as Consciousness Fades Even more interestingly, these quantum entanglement-related signals appeared strongly only when the subjects were in a state of conscious awareness. When the subjects' consciousness faded, such as when falling asleep, the signals invariably and gradually disappeared. This is a strong experimental indication that macroscopic water proton spins related to brain physiology are mediating entanglement through unknown brain functions, further suggesting that the foundation of human brain computational processes and consciousness could be strictly non-classical. This research leaves open the possibility that the human brain operates effectively like a highly complex quantum computer, and it is expected to bring a groundbreaking paradigm shift in neuroscience, psychology, medicine, and the development of next-generation artificial intelligence in the future.