Myosin Coherence
- Written, 25 June 2000

Quantum physics and molecular biology are two disciplines that have evolved relatively
independently. However, recently a wealth of evidence has demonstrated the importance
of quantum mechanics for biological systems and thus a new field of quantum biology is
emerging. Living systems have mastered the making and breaking of chemical bonds, which
are quantum mechanical phenomena. Absorbance of frequency specific radiation (e.g.
photosynthesis and vision), conversion of chemical energy into mechanical motion (e.g. ATP
cleavage) and single electron transfers through biological polymers (e.g. DNA or proteins)
are all quantum mechanical effects. Hopefully, the merging of disciplines known as
nanotechnology will remove the interface between quantum physics and biology.
In a paper titled 'The Importance of Quantum Decoherence in Brain Processes,' [1] Max
Tegmark sought to prove that the brain is too warm to maintain the coherence required for
quantum computation. From the results of his calculations, Tegmark claims that, "there is
nothing fundamentally wrong with the current classical approach to neural network
simulations." This statement contradicts the hypothesis that the brain functions as a
quantum computer, originally proposed by Roger Penrose [2]. Tegmark's claim was
amplified by a recent report in Science beginning with the sentence, 'Sir Roger Penrose is
incoherent, and Max Tegmark says he can prove it.' [3] However, the computations carried
out by Tegmark relied on a value of 310K for the temperature in his model of the neuron.
While the average kinetic energy (temperature) of an entire brain cell may be 310K, the
most fundamental characteristic of life is that it is not at equilibrium and thus, our statistical
method for measuring temperature breaks down at small sizes, especially at the nanoscale.
Biological systems are known to have ways of manipulating local temperatures. For
instance, Koichiro Matsuno has determined by the postulate of black body radiation
measurements that actomyosin complexes (abundant in the axons of nerve cells) can reach
local temperatures as low as 1.6*10-3K [4]. Matsuno argues that actomyosin functions as a
heat engine (a device that converts heat energy into mechanical energy) that is able to
maintain a constant velocity due to quantum mechanical coherence and entanglement.

[1] Max Tegmark, 'The Importance of Quantum Decoherence in Brain Processes,' Phys. Rev.
E 61 (2000) 4194-4206. homepage.
[2] Roger Penrose, The Emperor's New Mind : Concerning Computers, Minds, and the Laws
of Physics, Penguin USA 1991.
[3] Charles Seife, 'Cold Numbers Unmake the Quantum Mind' Science, (Feb. 4, 2000) 287,
No. 5454, p791.
[4] Koichiro Matsuno, 'Cell motility as an entangled quantum coherence,' BioSystems (1999)
51, 15-19. Koichiro Matsuno's Homepage