Guarding the Wall: tunnels, bridges and tendrils

[Prashant Kumar]

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 <javascript:_e({},
> 'cvml', 'siva.prashant.kumar at gmail.com');>>
> To: bandwraith <bandwraith at aol.com <javascript:_e({}, 'cvml',
> 'bandwraith at aol.com');>>; pynchon -l <pynchon-l at waste.org<javascript:_e({}, 'cvml', '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:
>
> Replying from work, so...
>
> If you meet any "new agers" who are capable of healing "old age," contact
> me immediately. Telepathy is OK.  : )
>
> I'm fine with "the sociological," although I make no claims of expertise
> in that field, let alone quantum theory, or any other field, for that
> matter. I'm just a regular person operating on common sense. Given that, a
> few queries:
>
> Does the entropy of the system under investigation increase after making a
> measurement? If we know nothing about the state of the system prior to
> making a measurement, and entropy increases after interrogation, does that
> mean that we know less than nothing after measurement?
>
> Where do we draw the line between the system being measur
>
>
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