Thursday, January 28, 2016


A year ago I promised myself that I would continue chipping away at decoherence. During the last couple of days I reviewed "Demystifying decoherence and the master equation of quantum Brownian motion" by John King Gamble and John F. Lindner .. and I finally get the drift. My February resolution is to take up pen and paper and work through the details seriously rather than just superficially reading around it.

This is how Gamble and Lindner introduce their paper:
"The details of decoherence theory are sufficiently complicated to discourage students and physicists from other fields to pursue a basic understanding of decoherence. The available literature is aimed at an advanced audience and contains significant gaps for most physicists.

"In this paper we attempt to rectify this situation by making the underlying concepts associated with decoherence accessible to a more general audience. We begin in Sec. II by introducing the concept of a state operator, an object of central importance to quantum decoherence theory, through a simple example first developed by Bernstein. We consider a rudimentary universe consisting of quantum particles and an “environment” randomized by a roulette wheel, and show that this randomization leads to diagonalization of the state operator and the emergence of classical behavior."
Now that I have immersed myself in outer products, projection operators, density matrices and expected values, the wood is finally emerging from the trees.


My other resolution for February is to revisit "The Vital Question: Why is life the way it is?" by Nick Lane. Universally acclaimed as groundbreaking and brilliant (which it is), this book is not an easy read and has defied concise summarization.

Nick Lane explains how the first cell might have got going from inorganic precursors. This involves a detailed review of the most elementary mechanisms of cellular operation: membrane metabolism, protein synthesis, bioenergetics and cell-replication. In computer terms, it's like microprocessor analysis at the sub-gate level.

I am determined to internalise it sufficiently to write a proper review.


Clare and myself walked to Wookey Hole this morning under bright sunshine and a pure blue sky, accompanied by a chilly wind. On arrival at an empty Wookey Hole Inn we asked for hot chocolate. In my case this is always more in hope than expectation: the drink almost invariably arrives lukewarm.

And so it was to be. The young woman who made the drinks was interesting: Barbie looks - very slim; tight trousers with tucked-in top; an over-made-up, rather pinched face. She made an art form of failing to meet my eye, studiously talking in a peremptory fashion to points adjacent to my head. I said to Clare afterwards, "I doubt she'll last."


The Amazon elves have done their work and a big parcel arrived this morning. After the Xylitol chewing gum, perhaps the smallest entity in the box was this.

Julian Barnes' new novel recounts how Shostakovich survived Stalin (review). The book is for Clare, who studied the composer during her OU arts unit.

By far the heaviest constituent was the package of six large jars of sauerkraut you see above. I had watched one of those cute medical programmes featuring that doctor who is a twin and who has that beard and who tries stuff out .. and sauerkraut is apparently a superfood for your gut biome. Well, we here just love our gut biomes and so I decided they needed a treat.

I am waiting for Clare's smile of delight once she gets in from the garden and has had a chance to absorb (sic) this addition to our already rather over-stuffed pantry. A side-dish of sauerkraut, anybody?


This Zika virus never used to be so bad; it might have mutated. I was all doom and gloom over Ebola and yet, thankfully, the epidemic burned itself out before it hit Europe. Let's hope we get lucky again.

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