I'd like to introduce you to an emerging area of science.
One that is still speculative, but hugely exciting.
It's certainly one that's growing very rapidly.
Quantum biology asks a very simple question.
Does quantum mechanics, that weird and wonderful, and powerful theory
of the subatomic world of atoms and molecules
that underpins so much of modern physics and chemistry, also play
a role inside the living cell?
In other words, are there processes, mechanisms, phenomena in living organisms
that can only be explained with a helping hand from quantum mechanics.
Now, quantum biology isn't new. It's been around since the early 1930s.
But its only in the last decade or so, that careful experiments
in biochemistry labs, using spectroscopy that have shown clear, firm evidence
that there are certain specific mechanisms that require quantum mechanics
to explain them.
Quantum biology brings together quantum physicists, biochemists,
molecular biologists.
It's a very interdisciplinary field.
I come from quantum physics. So, I'm a nuclear physicist.
I've spent more than three decades trying to get my head around quantum mechanics.
One of the founders of quantum mechanics, Neil Bohr said,
If you're not astonished by it, then you haven't understood it.
So, I sort of feel happy that I'm still astonished by it and that's a good thing.
But it means I study the very smallest structures in the universe.
The building blocks of reality.
If we think about the scale of size, start with something, an everyday object
like the tennis ball, and just go down orders of magnitude and size.
From the eye of a needle, down to a cell, down to a bacterium, down to an enzyme.
You eventually reach the nano world.
Now, nanotechnology may be a term you've heard of.
A nanometer is a billionth of a meter.
My area is the atomic nucleus, which is the tiny dot inside an atom.
It's even smaller in scale.
This is the domain of quantum mechanics, and physicists and chemists have had
a long time to get used to it.
Biologists on the other hand have got off lightly, in my view.
They are very happy with their balls-and-sticks models of molecules.
(Laughter)
The balls are the atoms, the sticks are the bonds between the atoms
and when they can't build them physically in the lab,
nowadays they have very powerful computers that will simulate a huge model.
This is a protein made up of 100,000 atoms.
It doesn't really require much in the way of quantum mechanics to explain it.
Quantum mechanics was developed in the 1920s.
It is a set of beautiful and powerful mathematical rules and ideas
that explain the world of the very small.
And it's a world that very different from our everyday world
made up of trillions of atoms.
It's a world built on probability and chance.
It's a fuzzy world.
It's a world of phantoms, where particles can also behave like spread out waves.
If we imagine quantum mechanics or quantum physics, then as
the fundamental foundation of reality itself.
That's not really surprising that we say quantum physics
underpins organic chemistry.
After all, it gives us the rules that tells us the rules that tell us
how the atoms fit together to make organic molecules.
Organic chemistry, scaled up in complexity gives us molecular biology,
which of course leads to life itself.
So, in a way, it's sort of not surprising.
It's almost trivial.
Say, well of course life ultimately must depend of quantum mechanics
-- so does everything else.
So does all inanimate matter, made up of trillions of atoms.
Ultimately, there's a quantum level that we know where we have to delve
into this weridness.
But in everyday life, we can forget about it.
Because once you put together trillions of atoms, that quantum weirdness
just dissolves away.
Quantum biology isn't about this. Quantum biology isn't this obvious.
Of course quantum mechanics underpins life at some molecular level.
Quantum biology is about looking for the non-trivial, the counterintuitive
ideas in quantum mechanics and to see if they do indeed play an important role
in describing the processes of life.
Here is my perfect example of the counterintuitiveness
of the quantum world.
This is the quantum skiier.
He seems to be intact, he seems to be perfectly healthy.
And yet, he seems to have gone around both sides of that tree at the same time.
Well, if you saw some tracks like that you'd guess some sort of stunts of course.
But in the quantum world, this happens all the time.
Particles can multitask, they can be in two places at once.
They can do more than one thing at the same time.
Particles can behave like spread out waves.
It's almost like magic.
Physicists and chemists have had nearly a century of trying
to get used to this weirdness.
I don't blame the biologists for not having or wanting to learn
quantum mechanics.
You see, this weirdness is very delicate and we physicists work very hard
to maintain it on our labs.
We sort of cool our system down to near absolute zero,
We carry out our experiments in vacuums, we try and isolate it
from any external disturbance.
That's very different from the warm, messy, noisy environment of a living cell.
Biology itself, if you think of molecular biology, seems to have done very well
in describing all the processes of life, in terms of chemistry.
Chemical reactions!
And these are reductionist, deterministic chemical reactions showing that
essentially life, is made of the same stuff as everything else,
and if we can forget about quantum mechanics in the macro world,
then we should be able to forget about it in biology, as well.
Well, one man begged to differ with this idea.
Erwin Schrödinger, he of Schrödinger's Cat fame, an Austrian physicist.
He was one of the founders of quantum mechanics in the 1920s.
In 1944, he wrote a book called "What is Life?"
It was tremendously influential.
It influenced Francis Crick and James Watson,
the discoverer's of the double helix structure of DNA.
To paraphrase a description in the book, he says, at the molecular level,
living organism have a certain order, a structure to them that's very
different from the random thermodynamic jostling of atoms and molecules
in inanimate matter of the same complexity.
In fact, living matter seems to behave in its order, in its structure
just like inanimate matter cooled down to near absolute zero,
where quantum effects play a very important role.
There's something special about the structure, the order
inside of living cell.
So, Schrödinger speculated that maybe quantum mechanics plays a role in life.
It's a very speculative, sort of far-reaching idea and it didn't
really go very far.
But, as I mentioned at the start, in the last 10 years
there have been experiment emerging, showing where some of these certain
phenomena in biology, do seem to require quantum mechanics.
Now, I want to share with you just a few of the exciting ones.
This is one of the best known phenomena in the quantum world.
Quantum tunneling.
The box on the left, shows the wavelike spread out distribution of quantum entity.
A particle, like an electron.
Which is not a little ball bouncing off a wall.
It's a wave that has a certain probability of being able to permeate through
a solid wall, like a phantom leaping through to the other side.
You can see a faint smudge of light in the right hand box.
Quantum tunneling suggests that a particle can hit an impenetrable barrier and yet,
somehow, as if by magic, disappear from one side and reappear on the other.
The nicest way of explaining it, is if you want to throw a ball
over a wall, you have to give it enough energy to get over the top of the wall.
In the quantum world, you don't have to throw it over the wall.
You can throw it at the wall and three's a certain non-zero probability that it'll
disappear on one side, and reappear on the other.
This isn't speculation, by the way, we're happy
-- i'm sorry, happy is not the right word.
(Laughter)
We are familiar with this.
(Laughter)
Quantum tunneling takes place all the time, in fact
it's the reason our sun shines.
The particles fuse together and the sun is turning hydrogen into helium
through quantum tunneling.
Back in the 70s and 80s, it was discovered that quantum tunneling also takes place
inside living cells.
Enzymes, those workhorses of life, the catalysts of chemical reaction.
Enzymes are biomolecules that speed up chemical reactions in living cells.
By many, many orders of magnitude.
And it's always been a mystery how they do this.
Well, it was discovered that one of the tricks that enzymes have evolved
to make use of, is by transferring subatomic particles, like electrons
and indeed protons, from one part of a molecule to another via
quantum tunneling.
It's efficient, it's fast, it can disappear
-- a proton can disappear from one place and a reappear on the other.
Enzymes help this take place.
This is research that's been carried out back in the 80s, particularly by a group
Berkeley, Judith Klinman.
Other groups in the UK have now also confirmed that enzymes really do this.
Research carried out by my group -- so I mentioned I'm a nuclear physicist,
but I realize I've got these tools of using quantum mechanics
in atomic nuclei and so can apply those tools in other areas, as well.
One question we asked was, whether quantum tunneling plays a role
in mutations in DNA.
Again, this is not a new idea. It goes all the way back to the early 60s.
The two strands of DNA, the double helix structure are held together by rungs,
it's like a twisted ladder.
And those rungs of the ladder are hydrogen bonds.
Protons that act as the glue between the two strands.
So, if you zoom in, what they're doing is holding these large molecules,
nucleotides, together.
Zoom in a bit more.
So, this a computer simulation.
The two white balls in the middle are protons and you can see that
it's a double hydrogen bond.
One prefers to sit one side, the other on the other side of the stands.
The two strands of the vertical lines going down, which you can't see.
It can happen that these two protons can hop over.
Watch the two white balls. They can jump over to the other side.
If the two strands then separate, leading to the process of replication,
and the two protons are in the wrong positions, this can lead to a mutation.
This has been known for half a century.
The question is how likely can they do that, and if they do, how do they do it?
Do they jump across, like the ball going over the wall?
Or can they quantum tunnel across, even if they don't have enough energy?
Early indications suggest that quantum tunneling can play a role here.
We still don't know yet how important it is, it's still an open question.
It's speculative, but it's one of those questions that it is so important,
that if quantum mechanics plays a role in mutations, surely this must
have big implications, to understand certain types of mutations, possibly even
those that lead to turning a cell cancerous.
Another example of quantum mechanics in biology is quantum coherence
and one of the most important process in biology, photosynthesis.
Plants and bacteria taking sunlight, using that energy to create biomass.
Quantum coherence is the idea of quantum entities multitasking.
It's the quantum skier.
It's an object that behaves like a wave, so that it doesn't just move
in one direction or the other, but can follow multiple pathways at the same time.
Some years ago, the world of science was shocked when a paper was published
showing experimental evidence, that quantum coherence takes place
inside bacteria, carrying out photosynthesis.
The idea is that the photon, the particle of light, the sunlight,
the quantum of light, captured by a chlorophyl molecule, is then delivered
to what's called the reaction center where it can be turned into chemical energy.
And in getting there, it doesn't just follow one root, it follows multiple
pathways at once, to optimize the most efficient way of reaching the reaction
center, without dissipating as waste heat.
Quantum coherence taking place inside a living cell.
A remarkable idea, and yet evidence is growing almost weekly with new papers
coming out, confirming that this does indeed take place.
My third and final example is the most beautiful, wonderful idea.
It's also still a very speculative, but I have to share it with you.
The European Robin migrates from Scandinavia, down to the Mediterranean
every autumn and like a lot of other marine animals and even insects,
they navigate by sensing the Earth's magnetic field.
Now the Earth's magnetic field is very, very weak.
It's 100 times weaker than a fridge magnet and yet
it affects the chemistry, somehow, within a living organism.
That's not in doubt, a German couple of ontologists
Wolfgang and Roswitha Wiltschko, in the 1970s confirmed that indeed
the robin does find it's way by somehow sensing the Earth's magnetic field,
to give it directional information, a built-in compass.
The puzzle, the mystery was how does it do it?
Well, the only theory in town, we don't know if it's the correct theory,
but the only theory in town, is that it does it via something called
quantum entanglement.
Inside the robin's retina -- I kid you not.
Inside the robin's retina, is a protein called cryptochrome,
which is light sensitive.
Within cryptochrome, a pair of electrons are quantum entangled.
Now quantum entanglement is when two particles are far apart and yet somehow
remain in contact with each other.
Even Einstein hated that idea, he called it spooky action at a distance.
If Einstein doesn't like it, then we can all be uncomfortable with it.
Two quantum entangled electrons within a single molecule, dance a delicate dance
that is very sensitive to the direction the bird flies
in the Earth's magnetic field.
We don't know if it's the correct explanation, but wow wouldn't it be
exciting if quantum mechanics helps birds navigate.
Qunatum biology is still in it infancy. It's still speculative.
But I believe it's built on solid science.
I also think that in the coming decade, or so, we're going to start to see
that actually it pervades life, that life has evolved tricks that utilize
the quantum world.
Watch this space.
Thank you.
(Applause)