Why the brain is probably not a quantum computer

Pentti O. A. Haikonen

C Jones

No, this does NOT require that your brain uses entangled atomic particles for computational primitives; No, this does NOT grant your brain super(computer) powers; No, this does NOT instantly give you a deep understanding of probability theory; No, this does NOT stretch your brain out across parallel multiverses; and, No, this does NOT allow your brain to (necessarily) factor large integers or solve any instance of an NP-Hard problem in polynomial time. Rather, what this DOES is give your brain a model of computation evolved for representing probabilistic states of the world with information encoded in vectors of positive or negative complexnumbers.

Herbert S. Green, T. Triffet

Andrei Yu. Khrennikov

We present a contextualist statistical realistic model for quantum-like representations in physics, cognitive science and psychology. We apply this model to describe cognitive experiments to check quantum-like structures of mental processes. The crucial role is played by interference of probabilities for mental observables. Recently one of such experiments based on recognition of images was performed. This experiment confirmed our prediction on quantum-like behaviour of mind. In our approach ``quantumness of mind'' has no direct relation to the fact that the brain (as any physical body) is composed of quantum particles. We invented a new terminology ``quantum-like (QL) mind.'' Cognitive QL-behaviour is characterized by nonzero coefficient of interference $λ.$ This coefficient can be found on the basis of statistical data. There is predicted not only $\cos θ$-interference of probabilities, but also hyperbolic $\cosh θ$-interference. This interference was never observed for physical systems, but we could not exclude this possibility for cognitive systems. We propose a model of brain functioning as QL-computer (there is discussed difference between quantum and QL computers).

Shan Gao

Based on the PBR theorem about the reality of the wave function, we show that the wave function assigned to a cognitive system, which is used to calculate probabilities of thoughts/judgment outcomes in quantum cognitive models, is a representation of the cognitive state of the system. In short, quantum cognition implies quantum minds. Furthermore, the principle of psychophysical supervenience requires that a quantum mind must supervene on a quantum brain.