Argument against Max Tegmark's hot brain thesis in Phys Rev Lett

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He further argued that this non-algorithmic process in the brain required ... and notably by the physicist, Max Tegmark, who calculated that quantum states ...
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In summary, the brain is indeed warm. The assumption/prediction by quantum .... As several of these are aimed specifically at the Penrose-Hameroff Orch 'OR' model, .... Tegmark. a. Max Tegmark. In an attempt to refute quantum models of ...
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Stuart Hameroff. University of Arizona. Non-conscious/. Unconscious Conscious .... But the brain is too warm and wet for delicate. quantum effects !? Decoherence. Max Tegmark calculated microtubule decoherence ...
www.quantumconsciousness.org/consciouspilotfinal.ppt"Entanglement generation and distribution over long distances is crucial to the realization of large-scale quantum computation and information tasks, including teleportation, memories and repeaters, and secure key distribution [1]. ...

On the other hand:

"Systems with finite correlation length, such as the 1D Heisenberg and XX models, allow for sizeable ground-state end-to-end entanglement, independent of the size of the system, provided that simple patterns of site-dependent couplings are se- lected. This phenomenon has been termed long-distance entanglement (LDE) [4]. It can be optimized against thermal decoherence in models with more sophisticated patterns of couplings [5], and might be implemented using suitably engineered atom-optical systems, including optical lattices and coupled cavity arrays [5,6]. However, its thermal instability remains a paramount obstacle against possible implementations."

Does this happen in the living brain that must be optimized against thermal decoherence?

"we consider the general problem of generating and distributing entanglement between distant and noninteracting quantum systems. We discuss the prop- erties of renormalization, amplification, and scalability of end-to-end entanglement in quantum many-body systems. From this investigation there emerges naturally the concept of modular entanglement. Specifically, we will show that size-independent end-to-end entanglement arises in the ground state of modular systems constituted by a set of identically interacting moduli of arbitrarily fixed size. This general type of entanglement at long distances, termed modular
entanglement (ME), includes LDE as the particular case realized in systems formed from two-qubit moduli.

We will show that a most relevant feature of ME is its enhanced stability against thermal decoherence, even by several orders of magnitude, compared to the case of simple LDE.  ...  given a fixed total number of qubits in the system, the stability of ME against thermal noise can be enhanced by orders of magnitude, compared to LDE, just by a proper tailoring of the number of moduli and of the single-modulus parameters,...

Moreover, being a static, ground-state property, there is no question on the time scale and speed at which ME can be created. These two aspects (enhanced thermal stability and exact ground state property) of ME are crucial advan- tages over schemes that suggest to create entanglement between distant qubits dynamically by, e.g., a sudden global quench much below a certain threshold temperature [11]. Indeed, dynamical schemes are intrinsically fragile to noise, imperfections, and thermal fluctuations. Moreover, they decay quickly with the size of the system. On the contrary, ME is a size-independent, exact ground-state property resilient to thermal decoherence and robust against imperfections. Its experimental realization and control would thus provide a relevant step towards the implementation of faithful large-scale quantum teleportation, memories, and repeaters, as well as the preparation of large multipartite states for measurement-based quantum computation."

PRL 106, 050501 (2011)
PHYSICAL    REVIEW    LETTERS    week ending 4 FEBRUARY 2011
Modular Entanglement
Giulia Gualdi, Salvatore M. Giampaolo, and Fabrizio Illuminati*
Dipartimento di Matematica e Informatica, Universita` degli Studi di Salerno, Via Ponte don Melillo, I-84084 Fisciano (SA), Italy; CNR-SPIN, and INFN Sezione di Napoli, Gruppo collegato di Salerno, I-84084 Fisciano (SA), Italy (Received 3 August 2010; revised manuscript received 7 November 2010; published 1 February 2011)