Nonabelions I

 As may be seen, the quantum mind idea that I have spent the most time on, is the idea that topological quantum states in microtubules exist and are robust. The mainstream idea of computing by braiding nonabelian anyons was an inspiration; also the idea of a Temperley-Lieb algebra hidden in a triangular lattice of qubits... I think a talk by Michael Freedman was important, but can't seem to find it. 

Anyway, this month there was a bit of hype about "simulated" nonabelions being created in an ordinary quantum computer. Originally I dismissed it as a distraction, but probably I should give it a closer look. So this is the reminder to myself. 

Mathematical advances

Sati and Schreiber have released a paper on cohomology for topological quantum states, and promise another paper on quantum computing in this medium. 

Hyperbole

It would be great if hyperbolic band theory (twitter explications #1 #2) could be applied to the microtubule, whose cylindrical shell is, after all, a kind of crystal, with a repeating fundamental domain (one per tubulin subunit). Unfortunately, a cylinder is geometrically flat, not curved (in the sense of Riemannian geometry)... 

Adenovirus gene therapy versus tauopathy

Recent Australian headlines about reversing Alzheimer's memory loss, via gene therapy targeting tauopathy, encouraged me to dust off this blog and to try to understand the paper. I have only skimmed it so far, but my impression is: they have mice genetically engineered to experience memory loss, via deletion of the gene for the enzyme p38γ. Then they use "adeno-associated virus" to introduce a working copy of the gene into the relevant brain tissues, and the mice memories are improved again.

I suspect that p38γ is relevant only for a highly specific form of Alzheimer's. But it is impressive that neural function can be restored by using a harmless virus to reinsert the necessary gene. 

added 7 October 2020: The title of this blog post is imprecise... adenovirus and adeno-associated virus are different. Adenovirus is being used e.g. in Russia's controversial coronavirus vaccine "Sputnik V". Adeno-associated virus is a smaller virus particle that tags along with adenovirus and in fact relies on adenovirus for replication. 

Anyons II

I always thought that the most serious criticism of "anyons in the microtubule" was that it would require internal electromagnetic fields of a strength that isn't there. But it turns out that, in the past decade, we've moved beyond the quantum Hall effect as the sole paradigm of topological states; and now there are ideas for how to create them, without needing an ambient magnetic field. (Chiral spin liquids, in particular, may be the key.) So the new edition of Sumathi Rao's anyon primer is welcome.

Anyons from M-theory

For many years I espoused the idea of "anyons in the microtubule", formed from (hypothetical) delocalized electrons subjected to the magnetic field of the action potential. Privately I also had notions of these electrons somehow condensing into a "brane" wrapping around the cylinder... Now Cumrun Vafa shows how it's done.

Nuclear bioqubits

It's a-priori outlandish - and I still prefer electrons in the microtubule - but good enough to blog: phosphorus nuclei as the qubits of the quantum brain. Just like Australia's quantum computer!