Afternoon. Carol has left to meet with
retired teacher friends at the Cooper Hawk in Kenwood. Yesterday you skimmed
the article below and dropped it on your Facebook page; today you read it more
carefully and like to hypothesize that human brains might also take advantage
of quantum properties and thus influence the development or the arrest of a
particular unique thought. You have underlined below what strikes you to
consider such an hypothesis. Add and post. - Amorella
** **
BBC Earth
“Organisms
might be quantum machines”
Few of us
really understand the weird world of quantum physics – but our bodies might
take advantage of quantum properties
•
By Martha Henriques
•
18
July 2016
If
there’s any subject that perfectly encapsulates the idea that science is hard
to understand, it’s quantum physics. Scientists tell us that the miniature
denizens of the quantum realm behave in seemingly impossible ways: they can
exist in two places at once, or disappear and reappear somewhere else
instantly.
The
one saving grace is that these truly bizarre quantum behaviours don’t seem to
have much of an impact on the macroscopic world as we know it, where “classical”
physics rules the roost.
Or,
at least, that’s what scientists thought until a few years ago.
Now
that reassuring wisdom is starting to fall apart. Quantum processes may occur
not quite so far from our ordinary world as we once thought. Quite the
opposite: they might be at work behind some very familiar processes, from the
photosynthesis that powers plants – and ultimately feeds us all – to the
familiar sight of birds on their seasonal migrations. Quantum physics might
even play a role in our sense of smell.
In fact, quantum effects could be
something that nature has recruited into its battery of tools to make life work
better, and to make our bodies into smoother machines. It’s even possible that
we can do more with help from the strange quantum world than we could without
it.
At
one level, photosynthesis looks very simple. Plants, green algae and some
bacteria take in sunlight and carbon dioxide, and turn them into energy. What
niggles in the back of biologists’ minds, though, is that photosynthetic
organisms make the process look just a little bit too easy.
It’s
one part of photosynthesis in particular that puzzles scientists. A photon – a
particle of light – after a journey of billions of kilometres hurtling through
space, collides with an electron in a leaf outside your window. The electron,
given a serious kick by this energy boost, starts to bounce around, a little
like a pinball. It makes its way through a tiny part of the leaf’s cell, and
passes on its extra energy to a molecule that can act as an energy currency to
fuel the plant.
The
trouble is, this tiny pinball machine works suspiciously well. Classical
physics suggests the excited electron should take a certain amount of time to
career around inside the photosynthetic machinery in the cell before emerging
on the other side. In reality, the electron makes the journey far more quickly.
What’s more, the excited electron
barely loses any energy at all in the process. Classical physics would predict
some wastage of energy in the noisy business of being batted around the
molecular pinball machine. The process is too fast, too smooth and too
efficient. It just seems too good to be true.
Then,
in 2007, photosynthesis researchers began to see the light.
Scientists spotted signs of quantum effects in the molecular centres for
photosynthesis. Tell-tale signs in the way the electrons were behaving opened
the door to the idea that quantum effects could even be playing an important
biological role.
This
could be part of the answer to how the excited electrons pass through the
photosynthetic pinball machine so quickly and efficiently. One quantum effect
is the ability to exist in many places at the same time – a property known as
quantum superposition. Using this property, the electron could potentially
explore many routes around the biological pinball machine at once. In this way
it could almost instantly select the shortest, most efficient route, involving
the least amount of bouncing about.
Quantum
physics had the potential to explain why photosynthesis was suspiciously
efficient – a shocking revelation for biologists.
“I
think this was when people started to think that something really exciting was
going on,” says Susana Huelga,
a quantum physicist at Ulm University in Germany.
Quantum
phenomena such as superposition had previously been observed mostly under
highly controlled conditions. Typical experiments to observe quantum phenomena
involve cooling down materials to bitingly cold temperatures in order to dampen
down other atomic activity that might drown out quantum behaviour. Even at
those temperatures, materials must be isolated in a vacuum – and the quantum
behaviours are so subtle that scientists need exquisitely sensitive instruments
to see what’s going on.
The
wet, warm, bustling environment of living cells is the last place you might
expect to see quantum events. “[But] even here, quantum features are still
alive,” Huelga says.
Of
course, just because these quantum features make an unexpected appearance in living
cells, it doesn’t necessarily mean that they’re playing a useful role. There
are theories as to how quantum superposition may be speeding up the process of
photosynthesis, but a hard link between this behaviour and a biological
function is still missing, Huelga says.
“The next step will be having
some quantitative results saying that the efficiency of this biological machine
is this due to quantum phenomena.”
Quantum
effects in biology aren’t just a quirk of plants and other organisms that do
the peculiar job of turning sunlight into fuel. They may also provide an answer
to a scientific puzzle that’s been around since the 19th Century: how migratory
birds know which way to fly.
In
a journey thousands of kilometres long, a migratory bird such as the European
robin will often fly to southern Europe or North Africa to escape particularly
cold winters. This journey over an unfamiliar landscape would be dangerous, if
not impossible, without a compass. Start the journey in the wrong direction and
a robin setting off from Poland might end up in Siberia rather than Morocco.
A
biological compass isn’t an easy thing to picture. If there was some form of
tiny magnetic iron needle-like structure spinning deep inside a robin’s brain
or eyes, biologists would almost certainly know about it by now. But no such
luck: a biological structure that could do the job has never been found.
Another theory, first proposed in
the late 1970s, suggested an alternative way birds might know which way to fly:
perhaps they carry a chemical compass that relies on quantum phenomena to tell
which way is north.
Peter Hore, a chemist at the
University of Oxford in the UK, says that such a chemical compass would work
with the help of molecules with excitable lone electrons, known as radicals,
and a quantum property known as spin.
Electrons
in molecules usually come in pairs, spinning in opposite directions and
effectively cancelling out each other’s spin. A “lone” electron spinning on its
own, though, isn’t cancelled out. This means it is free to interact with its
environment – including magnetic fields.
As
it turns out, Hore says, robins can become temporarily disorientated when
exposed to radio waves – a type of electromagnetic wave – of a particular range
of frequencies. If a radio wave has a frequency of just the same rate that an
electron spins, it could cause the electron to resonate. This is the same kind
of resonance you might experience when you sing in the shower – certain notes
sound a lot louder and fuller than others. Hitting the right radio wave
frequency will make the electron vibrate more vigorously in the same way.
But
what does this have to do with the idea that birds use a chemical compass? The
theory is that ordinarily, radicals at the back of the bird’s eye respond to
the Earth’s magnetic field. The magnetic field will cause the electron to leave
its spot in the chemical compass and start a chain of reactions to produce a
particular chemical. As long as the bird keeps pointing in the same direction,
more of the chemical will build up.
So the amount of this chemical
present is a source of information, generating signals in the bird’s nerve
cells. As part of many different environmental cues, this information will
inform the bird about whether it is pointing towards Siberia or Morocco.
The
radio wave observation is an important one because we would expect anything
that interferes with electron spin to be able, at least in principle, to
disrupt the chemical compass. It can be as useful to study why something
sometimes doesn’t work, as it is to study why it generally does work.
Even
so, the quantum compass remains an idea. It hasn’t yet been found in nature.
Hore has been focusing on finding out how the quantum compass can work in
principle, using molecules that theoretically ought to be able to do the job.
“We’ve
done experiments on model compounds to establish the principle that one can
make a chemical compass,” Hore says. These have helped to pin down some
molecules that do seem to be fit for the purpose of detecting magnetic fields,
he says. “What we don’t know is whether they behave in exactly the same way
inside a cell in the bird’s body.”
The magnetic compass is just part
of a complex and poorly understood system of navigation in birds, Hore says.
The quantum theory for how such a compass works may be the best out there so
far, but there’s still a lot of ground to cover to link up the behavioural
patterns of birds with the theoretical chemistry.
There
is one field that seems tantalisingly close to demonstrating the reality of
quantum biology, though: the science of smell.
Exactly
how our noses are capable of distinguishing and identifying a myriad of
differently shaped molecules is a big challenge for conventional theories of
olfaction. When a smelly molecule wafts into one of our nostrils, no one is yet
entirely sure what happens next. Somehow the molecule interacts with a sensor –
a molecular receptor – embedded in the delicate inner skin of our nose.
A
well-trained human nose can distinguish between thousands of different smells.
But how this information is carried in the shape of the smelly molecule is a
puzzle. Many molecules that are almost identical in shape, but for swapping
around an atom or two, have very different smells. Vanillin smells of vanilla,
but eugenol, which is very similar in shape, smells of cloves. Some molecules
that are a mirror image of each other – just like your right and left hand –
also have different smells. But equally, some very differently shaped molecules
can smell almost exactly the same.
Luca Turin, a chemist
at the BSRC Alexander Fleming institute in Greece, has been working to crack
the way that the properties of a molecule encode its scent. “There is something
very, very peculiar at the core of olfaction, which is that our ability to
somehow analyse molecules and atoms is inconsistent with what we think we know
about molecular recognition,” Turin says.
He
argues that the molecule’s shape alone isn’t enough to determine its smell. He
says that it’s the quantum properties of the chemical bonds in the molecule
that provides the crucial information.
According
to Turin’s quantum theory of olfaction, when a smelly molecule enters the nose
and binds to a receptor, it allows a process called quantum tunnelling to
happen in the receptor.
In
quantum tunnelling, an electron can pass through a material to jump from point
A to point B in a way that seems to bypass the intervening space. As with the
bird’s quantum compass, the crucial factor is resonance. A particular bond in the smelly molecule, Turin says, can resonate with
the right energy to help an electron on one side of the receptor molecule leap
to the other side. The electron can only make this leap through the
so-called quantum tunnel if the bond is vibrating with just the right energy.
When
the electron leaps to the other site on the receptor, it could trigger a chain
reaction that ends up sending signals to the brain that the receptor has come into
contact with that particular molecule. This, Turin says, is an essential part
of what gives a molecule its smell, and the process is fundamentally quantum.
“Olfaction
requires a mechanism that somehow involves the actual chemical composition of
the molecule,” he says. “It was that factor that found a very natural
explanation in quantum tunneling.”
The
strongest evidence for the theory is Turin’s discovery that two molecules with
extremely different shapes can smell the same if they contain bonds with similar
energies.
Turin predicted that boranes –
relatively rare compounds that are hard to come by – smelled very like sulphur,
or rotten eggs. He’d never smelt a borane before, so the prediction was quite a
gamble.
He
was right. Turin says that, for him, that was the clincher. “Borane chemistry
is vastly different – in fact there’s zero relation – to sulphur chemistry. So
the only thing those two have in common is a vibrational frequency. They are
the only two things out there in nature that smell of sulphur.”
While
that prediction was a great success for the theory, it’s not ultimate proof.
Ideally Turin wants to catch these receptors in the act of exploiting quantum
phenomena. He says they are getting “pretty close” to nailing those
experiments. “I don’t want to jinx it, but we’re working on it,” he says. “We
think we have a way to do it, so we’re definitely going to have a go in the
next few months. I think that nothing short of that will really move things
forward.”
Whether
or not nature has evolved to make use of quantum phenomena to help organisms
make fuel from light, tell north from south, or distinguish vanilla from clove,
the strange properties of the atomic world can still tell us a lot about the
finer workings of living cells.
“There
is a second way of seeing how quantum mechanics interacts with biology, and
that is by sensing and probing,” Huelga says. “Quantum probes would be able to
shed light on many interesting things in the dynamics of biological systems.”
And
whether or not nature got there first, it’s no excuse for us not to mix biology
with quantum phenomena to develop new technologies, she says. Making use of
quantum effects in biologically inspired photovoltaic cells, for instance,
could give solar panels a huge boost in efficiency. “At this very moment there
is quite a lot of activity in organic photovoltaics, to see whether with
natural or artificial structures one can have an enhanced efficiency that
exploit quantum effects.”
So even if alternative, as yet
entirely unknown mechanisms emerge for these stubborn biological puzzles,
biologists and quantum physicists certainly won’t have seen the last of each
other. “This will definitely be a story with a happy end,” she says.
Selected and edited from -- http://www.bbcDOTcom/earth/story/20160715-organisms-might-be-quantum-machines?
Late afternoon. You just completed reading
the essay, “The Origins of Speech” by Thomas Wolf in the August 2016 edition of
Harper’s. From the concluding page (40):
“Chomsky and the trio go over aspect after aspect of
language . . . but . . . there is something wrong with every hypothesis . . .
they try to be all encompassing . . . but . . . in the end any attentive soul
reading it realizes that all 5,000 words were summed up in the very first
eleven words of the piece, which read: ‘The evolution of the faculty of
language largely remains an enigma.’” - Amorella
1811
hours. So, here we are, the faculty of language is mostly unknown. We have to
have thought of language first, otherwise, why invent it? Necessity for
survival comes first. Animals communicate one way or another. Cells have to
communicate first. Obviously ‘speech’ is not needed. (1817) – Carol arrives home.
You took time to watch a new “Rizzoli and
Isles” and a bit of MSNBC before calling it a TV night. Later, dude. - Amorella
Evening.
You spent some time putting December 2009 in the correct day order and deleting
much of the material not need for this Dewdrop. – Amorella
2141
hours. Quick thoughts. There is not much for Dewdrop in December about half the
month is focusing on the beginning of book four, which has since been scrapped.
This was a nice break though, that is, a different subject. It appears I was
feeling like book four was going to come and go quickly like the first three
books did – one a year. Obviously, I had no idea of how this was going to be. I
remember I had a thought somewhere about this time that it would be cool if my
description of HeavenOrHellBothOrNeither would be a facsimile of the real thing.
Somewhere deep in my mind I was hoping that Amorella really was somewhat akin
to an angelic like figure, something really beyond my imagination. At the very
least I thought Amorella would help me pull it off even if she really was
nothing but imagination personified, so to speak.
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