Quantum Models of Consciousness from a Quantum Information Science Perspective

TL;DR

Addresses whether quantum effects can play a role in brain function by evaluating Orch OR, CEMI, and the Posner cognition model from a quantum-information lens. The authors develop a toy Posner-cluster model to study entanglement preservation using a central-spin plus buffer-spin geometry and a dressed-mode transformation that yields non-Markovian dynamics. They quantify coherence and entanglement with measures such as the $l_1$ norm of coherence and the logarithmic negativity $E_N$, and show that tetrahedral buffer geometries can enhance quantum information protection. While not proving Fisher's cognition proposal, the work demonstrates how quantum-information tools can inform biologically plausible quantum brain hypotheses and guides future experimental tests.

Abstract

This perspective explores various quantum models of consciousness from the viewpoint of quantum information science, offering potential ideas and insights. The models under consideration can be categorized into three distinct groups based on the level at which quantum mechanics might operate within the brain: those suggesting that consciousness arises from electron delocalization within microtubules inside neurons, those proposing it emerges from the electromagnetic field surrounding the entire neural network, and those positing it originates from the interactions between individual neurons governed by neurotransmitter molecules. Our focus is particularly on the Posner model of cognition, for which we provide preliminary calculations on the preservation of entanglement of phosphate molecules within the geometric structure of Posner clusters. These findings provide valuable insights into how quantum information theory can enhance our understanding of brain functions.

Figures (6)

• Figure 1: Schematic representation of the cylindrical microtubule structure formed by $\alpha \beta$-tubulin dimers ($\alpha$ in orange, $\beta$ in green), highlighting the tryptophan (Trp) network. The Trp residues are depicted as stars, illustrating their collective emission of light, a phenomenon associated with superradiance.
• Figure 2: Schematic representation of the CEMI (Conscious Electromagnetic Information) field theory, illustrating how the electromagnetic (EM) field generated by neural networks interacts with and influences neuronal activity.
• Figure 3: Schematic representation of two Posner clusters, each composed of nine calcium atoms and six phosphate ions (Ca$_{9}$(PO4)$^{3-}_{6}$). The diagram illustrates how two phosphate ions can become entangled between different Posner clusters.
• Figure 4: Logarithmic negativity , $E_N$, of the reduced state composed on the two entangled spins with respect to dimensionless time, $t$. Here, all the results refer to the model with fully connected buffer spins (for $N=5$ the interaction between spin 2 and spin 6 is missing). (a) $N=2$. (b) $N=3$. (c) $N=4.$ (d) $N=5$.
• Figure 5: The first column represents the number of buffer spins, $N$. Column A represents the non-interacting buffer spins. Column B shows the interacting buffer spins. Column C shows the dressed buffer modes after the Hamiltonian transformation which is represented by the curved arrows. For $N=2,3,4$, the dressed mode $\tilde{2}$ can be associated with a collective spin. In the original representation (column B), all spin couplings are identical. In the new representation, that is, the dressed picture (column C), the couplings vary as follows: $\tilde{g}_{12} = 1.41G$ for $N=2$, $\tilde{g}_{12} = 1.73G$ for $N=3$, $\tilde{g}_{12} = 2G$ for $N=4$, and $\tilde{g}_{12} = -2.23G$, $\tilde{g}_{14} = 0.21G$ for $N=5$.