Guarding the Wall: tunnels, bridges and tendrils

[alice wellintown]

I doubt it. It is so poorly written that unless a reader is very familiar
with the topic he will have a great deal of difficulty making out what the
authors are trying to explain. Minor interference is now quite common in
science publications, but when it is compounded with grammar and usage and
punctuation errors or typos or copy errors, it often makes an article
unreadable, even for those who are expert in the subject matter and adept
at reading English with interference.

On Thursday, April 25, 2013, Prashant Kumar wrote:

> It's not very well written. I looked at their
> crash-course-in-quantum-mechanics section and it is very confused. I'm not
> sure it's worth the effort.
>
> P.
>
> On Thursday, 25 April 2013, wrote:
>
> Thank you for the Review Article (not attached here)- very approachable
> and interesting. Next I'm going to try this:
>
> http://arxiv.org/ftp/arxiv/papers/1304/1304.0683.pdf
>
> Which was referenced in the Wikipedia article on Quantum Biology. Wish me
> luck.
>
>
>  -----Original Message-----
> From: Prashant Kumar <siva.prashant.kumar at gmail.com>
> To: bandwraith <bandwraith at aol.com>; pynchon -l <pynchon-l at waste.org>
> Sent: Tue, Apr 23, 2013 1:28 am
> Subject: Re: Guarding the Wall: tunnels, bridges and tendrils
>
>  Good questions. Measurement erases the information stored in the system (entropy
> relates thermodynamics and information theory<http://en.wikipedia.org/wiki/Maxwell%27s_demon#Criticism_and_development>).
> And so yes, we know nothing about the system after measurement because the
> *act *of* *measurement causes decoherence from quantum to classical. This
> why quantum computing is so difficult to realise in practice.
>
>  The system will have certain degrees of freedom; basically places where
> it can store energy and information. The formalism differentiates between
> classical (environment) and quantum (system) degrees of freedom. In an
> actual experiment the system under study will usually be thermally isolated
> from the apparatus. The equipment is separated into thermal stages, with
> the quantum system at the lowest temperature stage. See here<http://en.wikipedia.org/wiki/Dilution_refrigerator>:
> the sample measured is in the section labelled "vacuum".
>
>  As for photosynthesis, this is one of the things covered in the quantum
> bio nature review. I've attached it. The first few sections are
> surprisingly readable. The reason why quantum coherence is maintained is
> rather complex. From the article:
>
>  Evidence, both theoretical and experimental, does hint that the
> non-perturbative and non-Markovian environment can enhance
> both the coherence time[19] and the efficiency of the excitation
> transport[39]. Similarly, a recent analysis argued that coherent vi-
> bronic excitations may play an important role in the coherent oscil-
> lations seen in experiments[40, 42]. However, the role of correlations
> between the baths of different BChl molecules is still not fully un-
> derstood. Recent work[39] showed that the correlations can in princi-
> ple improve the efficiency in some cases, but can also decrease it, and
> that there is an optimal overall noise level. In comparison, molec-
> ular dynamics simulations[43, 44] indicated that the uncorrelated-bath
> approximations may hold, and thus independent-bath models may
> be sufficient to explain any enhancement in efficiency. Ultimately,
> the real role of correlated-bath effects and vibronic excitations in
> photosynthetic units, FMO and otherwise, is still not clear, and
> requires further experimental studies.
>
>  Basically it looks like the protein complex that is responsible for this
> quantum coherent behaviour is a special kind of system ("non perturbative
> and non-Markovian environment") which has a kind of coupling that may be
> beneficial to coherence. I went to a conference last year where people were
> doing this stuff and it looked then like the precise reason for coherence
> was a tricky problem.
>
>  It should be noted that in other systems, notably graphene, we do
> observe quantum coherent energy transport (electrons grooving along as
> quantum wavefunctions, instead of particles, ballistically) at room
> temperature. So it isn't entirely without precedent. The important
> difference is that inorganic systems don't have irreducible environmental
> couplings (read: they aren't all squishy and alive). Which means that you
> need to do some really difficult *in vivo* experimentation to understand
> the problem. Last I checked (December 2012) this hadn't been done.
>
>  P.
>
>
> On 23 April 2013 02:49, <bandwraith at aol.com> wrote:
>
> R
>
>
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