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). 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: 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 measured and everything else?
I have seen reports suggesting that biological molecules, specifically those involved in photosynthesis, are capable of maintaining electrons in a state of super-position long enough, and of course many degrees kelvin hotter than your example, to allow the plant cell to perform the conversion with near 100% efficiency. Here's a reference:
http://www.sciencedaily.com/releases/2013/04/130419120954.htm
"Quantum effects are generally negligible in large, hot, disordered systems. Nevertheless, the recent ultrafast spectroscopy experiments in UChicago chemistry Prof. Greg Engel's laboratory have shown that quantum superpositions may play a role in the near perfect quantum efficiency of photosynthetic light harvesting, even at physiological temperatures."
What's your take?
-----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: Mon, Apr 22, 2013 8:05 am
Subject: Re: Guarding the Wall: tunnels, bridges and tendrils
Not quite. As decoherence is occurring we need to make measurements to ascertain the state of the system. We don't know anything before measurement.
As for his audience, the need you describe is universal. And different people do different things to satisfy it; your concerns are sociological. I've known a few "quantum healing" new agers. Let's just say their motivations weren't intellectual.
P.
On 22 April 2013 21:51, <bandwraith at aol.com> wrote:
Do you mean- How can you tell if there is a relationship before your measurement?
-----Original Message-----
From: Prashant Kumar <siva.prashant.kumar at gmail.com>
To: Keith Davis <kbob42 at gmail.com>; pynchon -l <pynchon-l at waste.org>
Sent: Mon, Apr 22, 2013 6:00 am
Subject: Re: Guarding the Wall: tunnels, bridges and tendrils
If y'all'll allow me the dubious honour of a triple post, let me preemptively clarify what I meant about "the relationship between the arrows". You might and therefore should ask: "How can I tell the `relationship' at the start from that at the end? Or, stated differently, is there a way to make precise the notion of `random' w.r.t. the bunch of arrows?". Good question, whomever. Think of a game of chess. If I give you a chessboard with an arrangement of pieces, with a little wikipedia you should be able to tell me whether the configuration is legal. In QM, there are similar rules defining how a quantum system (the bunch of arrows) can change in magnitude and direction while still retaining coherence, their "relationship". So when I get the chessboard I check for legality: based on successive measurements, I can probe the "evolution" of the arrows, and find out whether they've stayed kosher. It is usually possible to work this out given details of the environment system, however.
P.
On 22 April 2013 19:44, Prashant Kumar <siva.prashant.kumar at gmail.com> wrote:
And in the spirit of intuitive presentation I want to try to explain quantum coherence: Keith asked and I totally glossed over it. Imagine that you're sitting in a room with a pendulum hanging from the ceiling. This pendulum is oscillating at some frequency, in one dimension (back and forth only, none of this crazy elliptical shit). There is no air in the room, so we have to be quick. What happens if my neighbour upstairs starts playing music? The vibrations will kick my pendulum off course. Does it matter if it's speed metal or classic rock? Well, the bass will have some vibration frequency, and when this is close to that of the pendulum you get the strongest "coupling" between the two systems. This is a thermodynamic thing; there is energy transfer as per the 2nd going on. In practice music has a fairly wide band of frequencies, so you'll get coupling with either genre, but if instead of music we considered, say, a truck then the frequency of the engine noise matters.
Now, what does this have to do with quantum anything? Any time you want to get information out of a quantum system you have to measure it. This entails getting a whole load of fat classical apparatus and coupling it to the QM system. I want you to think of this QM system as a bunch of arrows in 3D space. Each starts at the origin, and has a defined direction and total length (or magnitude). The dimensions aren't spatial, however. You can think of each dimension as a number which indicates "the extent to which the system is state-{1,2,3}"; these are components which sum with direction to give the total state -- think back to adding vectors, or finding the hypotenuse given the two sides: this is a similar thing. Each number is the probability of finding the system in a given state upon measurement. This probabilistic construct is called a superposition state, and is uniquely quantum thing. Quantum coherence is the relationship that exists between all your arrows, before you couple it to some other system -- I'll call this latter "the environment". What happens upon coupling is that your 3D space becomes a lot larger -- the extra "dimensions" correspond to states in the environment. Let's for concreteness say we have 2, so (3+2)D.
Now things happen just like with the pendulum and the truck. Energy flows from the environment into our QM system, and the effect it has is to rotate our bunch of arrows, each independently of the other. To extend the classical analogy, what we have is a collection of pendulums each with a different oscillation frequency. So the music will cause them each to move differently. Then, when we go to measure our system -- to try to find out the values of the numbers belonging to the three state dimensions -- we have a problem. Our arrows now have 2 extra dimensions in which to play about in, but the same magnitude. This, as well as energy flowing into the QM system from the environment will have changed the values of the state-numbers. So if we measure, we don't see the same state we started out with: our initial quantum superposition has become a different one. The effect of this process over time is to destroy in its entirety the relationship between the arrows, to make the arrows point in random directions. This, my friends, is entropy at the quantum level.
So, what I was saying re quantum mechanics in the brain is that, at brain temperatures, this quantum decoherence (is the name for the loss of coherence via entropic action) will take almost no time to destroy any quantum superposition: the arrows will fly away from each other in some infinitesimal time. To retain quantum coherence in most systems you need to be at milliKelvin temperatures.
P.
On 22 April 2013 05:40, Keith Davis <kbob42 at gmail.com> wrote:
Prashant,
I really wish I could understand what you're saying here. Can you point me to something that helps to explain "quantum coherence"? I'm not even sure I understand this whole thread, but I'm interested.
kd
On Sun, Apr 21, 2013 at 7:55 AM, Prashant Kumar <siva.prashant.kumar at gmail.com> wrote:
My take on it is this: what DC and others does is manipulative (in that it does prey on people who must necessarily "trust the experts") and shits all over a nascent field; applications of quantum mechanics in the life sciences is only slowly being studied for all the damage new agers have done (academic jobs being the way they are, no newly minted PhD wants to risk his or her reputation on something so fringe. It's unreasonable to expect people to live as tortured maybe-geniuses). It's a technique of the right: teach the controversy. DC et al. in this article are attempting to blur the line (and there is one) between his horseshit and actual speculative science which exists outside the norm.
Quantum consciousness is a prime example: there is no way to maintain quantum coherence at the energy scale at which the brain operates. Now, this doesn't mean that quantum physics has no role in biology. Here is a wonderful review article detailing various applications. Turns out, magnetoception in pigeons may be quantum mechanical in nature! This is the kind of research which we don't hear about, thanks to these arseholes. I'm willing to bet reality is more interesting than anything Chopra could come up with.
P.
On 21 April 2013 21:28, <bandwraith at aol.com> wrote:
You mean... It's just another rope trick? : )
Thinking about it in general terms, I guess there're lots of "cracked pots"- scientific, religious, artistic, etc. Some are endearing, some more consciously manipulative and willing to prey on people's niavete. But I maintain that - if I can be excused the royal "we" here- we are all a little cracked in our own way, and its probably okay to embrace our inner crack-pot, just not too vehemently, lest we seal the cracks and it becomes a pressure cooker- just enough to foster a little empathy.
I was going to say something about the Liberty Bell, but I'm uncertain now. It's Sunday here. I'll go meditate on it for awhile.
-----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: Sun, Apr 21, 2013 5:31 am
Subject: Re: Guarding the Wall: tunnels, bridges and tendrils
This guy and his quantum mechanical snake oil...in the language of my people: "madarchod".
P.
On Saturday, April 20, 2013, wrote:
"...On the other side of the wall are lethal enemies and malefic magic. For centuries, no one has seen the zombie-like White Walkers who live on the other side of the wall, nor the dragons that once ravaged Westeros
.
Even so, after magic and zombies fell into disbelief, a hereditary band of guardians swore an oath to keep watch at the wall, generation after generation. TED has put itself in rather the same position. What the militant atheists and self-described skeptics hate is a certain brand of magical thinking that endangers science. In particular, there is the bugaboo of "non-local consciousness," which causes the hair on the back of their necks to stand on end. A layman would be forgiven for not grasping why such an innocent-sounding phrase could spell danger to "good science."
http://www.huffingtonpost.com/deepak-chopra/dear-ted-is-it-bad-scienc_b_3104049.html
--
www.innergroovemusic.com
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