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The importance of quantum decoherence in brain processes

Quantum Physics 2009-10-07 v2 Disordered Systems and Neural Networks Neural and Evolutionary Computing Biological Physics q-bio

Abstract

Based on a calculation of neural decoherence rates, we argue that that the degrees of freedom of the human brain that relate to cognitive processes should be thought of as a classical rather than quantum system, i.e., that there is nothing fundamentally wrong with the current classical approach to neural network simulations. We find that the decoherence timescales ~10^{-13}-10^{-20} seconds are typically much shorter than the relevant dynamical timescales (~0.001-0.1 seconds), both for regular neuron firing and for kink-like polarization excitations in microtubules. This conclusion disagrees with suggestions by Penrose and others that the brain acts as a quantum computer, and that quantum coherence is related to consciousness in a fundamental way.

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Cite

@article{arxiv.quant-ph/9907009,
  title  = {The importance of quantum decoherence in brain processes},
  author = {Max Tegmark},
  journal= {arXiv preprint arXiv:quant-ph/9907009},
  year   = {2009}
}

Comments

Minor changes to match accepted PRE version. 15 pages with 5 figs included. Color figures and links at http://www.physics.upenn.edu/~max/brain.html or from [email protected]. Physical Review E, in press