[Music] thank you very much Roger thank you John for the introduction well good evening everyone a pleasure to be here as John mentions I I follow an illustrious company after Steven hawy and Carlo relli um I should also mention that uh I about 12 13 years ago I set up um an annual lecture series for my physics department at the University of s and of course Roger Penrose was the inaugural speaker at that uh that series I recall our um uh or seminar organizer rushing around to find an an overhead projector for Roger's famous transparencies with his drawings of black holes event Horizons and and and light cones um so it's a pleasure to be here pleasure to to to be giving this this lecture this evening uh on Quantum biology I've I I see there there's a mixed audience here in terms of expertise well I'm guessing there is uh I I I hope there's going to be something for everyone uh I think those of you who don't have a a back a strong background in science there should be enough for you to follow the story uh and why this is a fascinating new field but hopefully there'll some nuggets from from my my own Recent research which will satisfy those more uh physics physically or mathematically inclined um let me just move that cursor away from the screen I really that bugs me there we go okay um normally when you learn physics uh when you do science at school it tends to be in these Silo subjects of physics chemistry biology uh and of course once you go on to study science at University you may choose to do uh an area of science that's at the interface between this biochemistry uh um physical chemistry or so on um the subject of quantum biology which I will um Define in a moment I guess sits somewhere in the middle because it requires expertise in physics whether it's biophysics or theoretical uh physics quantum mechanics uh computational chemistry quantum chemistry but also of course molecular biology now why why Quantum biology what's so what's so interesting there well of course and many of you will know that this is a subject that goes back many years back to Schrodinger's famous book what is life in the 1940s but just simply looking at the you know the scale of of of uh um objects in our world starting from something like a tennis ball which we would call uh which we would be able to describe using Newtonian mechanics you know the the the forces acting on the ball how it spins its angular momentum the way it bounces the way gravity um gives it a parabolic Arc through the air uh newtonium mechanics is enough to describe it but as we go in in power orders of magnitude smaller and smaller and smaller we get down to scales where Newtonian or classical mechanics breaks down and we need a new mechanics to describe uh objects in that world namely quantum mechanics now of course it's rather uh vague where we have to give up on classical mechanics and and use quantum mechanics but certainly down at the nanometer scale a billionth of a meter one would expect Quantum effects to start to kick in um I've deliberately put in objects and molecules of life here right down to the the double helix of DNA um to show show that the building blocks of life fall in this uh sort of rather uh vague area between classical and quantum mechanics I've spent most of my career before I got involved in in in in this area as a nuclear physicist so uh uh trying to study nuclear reactions and and developing ideas in Quantum scattering Theory to to determine the structure of atomic nuclei now you remember an atomic nucleus is made of protons and neutrons a nuclear physicist doesn't dig inside the protons and neutrons in general so we're not that interested in the internal Quark structure of those particles but the way the protons and neutrons arrange themselves in a nucleus according to the rules of quantum mechanics so I was very familiar with the need to use quantum mechanics to describe Atomic nuclei if we could get away with not using quantum mechanics or or having some sort of hybrid what's called semi-classical mechanics then we saw that as a Triumph because that tended to to sort of you know make the calculations easier but scale back up to the nanometer uh and uh and we are at structures that involve atoms and molecules albeit bonded together in in quite complex structures that nevertheless one might think should obey the the rules of quantum mechanics well of course physicists and chemists are used to using quantum mechanics we're we're coming up in this decade to celebrate the centinary of the development of of the theory by the likes of Neils bour and verer Heisenberg and and Schrodinger and others um so we've had a long time to get used to it in fact uh uh in in physics uh by the second half of the 20th century we had pretty much figured out the building blocks so far of of uh of matter of our universe the quarks and and and leptons and and the the force carrying particles the photon and the glue on and so on uh we wouldn't be able to have determined the building blocks of of of matter this these fundamental particles without having an understanding of the quantum World likewise in chemistry this is a modern periodic table by modern I mean if you look so to shine my my pointer over here element 118 ogan that's the heaviest synthesized element uh it's created just for a fraction of a second in a nuclear accelerator so you're not making bulk material you're making individual atoms of this new element before they radioactively Decay away an interesting point by the way ogan is named after a nuclear physicist not a chemist a nuclear physicist by the name of Yuri oganesian and he's the only living human today who has an element named after him there are many other elements named after people who are no longer with us um when mendelev first created the the chemical the the the table of elements of course there were only roughly half the number that we have today uh but what's interesting is that this classification the structure the the order of this um periodic table uh has pretty much remained the same based on the chemical and physical properties of all the elements that that we find but we can only understand why these elements are classified and ordered in this way with an understanding of the quantum world because it's the the rules of quantum mechanics that tell us how electrons arrange themselves in atoms and give these elements their properties so quantum mechanics is the bread and butter of much of physics and chemistry and we've got used to it what we haven't got used to yet I would argue is what it all means this is the Quantum skia see the tree looks fine there's no reason to think that he can't father children uh at some point and yet you see something like of course this is a cartoon but if you see something like this on YouTube you you you'd guess there's some trickery going on of course this sort of trickery is essentially what happens in the quantum realm all the time it's it's counterintuitive the mathematics of quantum mechanics works and it's fine it's powerful it's led us to this great understanding and and and and developing the whole of our modern world really so certainly modern Electronics but at its heart we are still struggling to figure out how it does or particles do what they do going in two directions at once or having sort of being behaving as though they're spread out over a larger volume Until You observe them and and force them to make up their minds what they want to be doing the famous schrodingers cat in the box but biologists by and large have avoided quantum mechanics I'm being deliberately cruel here um because biologist don't use balls and sticks models anymore they they have computers but but the idea here is that you know here you you have atoms bonded together the gray are the chemical bonds you know so you can see black is carbon white is hydrogen oxygen and nitrogen um the the the the elements uh so this is like a this is an organic molecule The Elements of Life of course I'm going to have to explain why I think life is special any different from in from inanimate matter of course these days I say we have computers and one can uh uh simulate uh the the the the vibrations of of uh of the various atoms in a large molecule this is a protein made of 100, atoms or more um what's interesting here is there isn't much quantum mechanics involved yes you might need certain basic Quantum rules to describe the chemical bonds that hold the atoms together but these are still classical balls bouncing around where's all that fuzziness where's all that probability where's all the the wav likee nature of matter that we hear about in the quantum world the problem is that biologists and molecular biologists haven't needed quantum mechanics molecular biology and genetics really evolved and developed going back to the 1930s when quantum mechanics were still very young and at the time a lot of quantum physics actually a lot of cons became molecular biologists uh but many of them sort of stro out of their labs and offices flush with the success of having been able to describe the physical world using their their equation their new equations of of quantum theory thought they'd give biologists a helping hand you know maybe maybe you need our help in explaining the building blocks of life and biologist said no thank you very much but we're doing fine by and large they have been doing fine but there has now emerged this new new area uh of quantum biology where it looks like we may need in certain features uh inside living systems uh to to describe what's going on using quantum mechanics if we think of quantum physics as the sort of the foundation uh of of of physical reality of our universe then clearly the rules of quantum physics would lead ultimately to organic chemistry they're made of atoms and quantum physics describes atoms quantum chemistry uh scaled up in complexity is molecular biology molecular biology gives us life so and naively one might say well of course life needs quantum mechanics but then so does everything else right everything's made of atoms why should life be treated any differently uh and and and talk about life needing quantum mechanics when any other system in animate matter is also made of the same building blocks that be that behave Quantum mechanically at that F fundamental level and so what is it that Quantum biology what distinguishes it from from uh uh you know what distinguishes life from non-life uh in terms of the need for quantum mechanics well we tend to talk about non-trivial Quantum effects um by which I mean things like Long Live Quantum coherence one of the arguments is that you know one of the the challenges for example facing Us in trying to build a quantum computer uh uh we distinguish it for itself from classical computers made of so Quantum made of cubits things can be uh doing two things at once not zero and one but zero and one at the same time um one of the challenges of course is that uh uh Quantum effects are delicate they're ephemeral they they they they dissipate very quickly in what's called decoherence so you want to hang on to them for as long as possible inside a living cell there are thousands of biochemical reactions taking place uh it's a busy hot messy noisy complex Place uh and a backof the envelope calculation will tell you that Quantum effects would disappear very very quickly far too quickly for for them to play any role in biology not necessarily so long live Quantum coherence is something you're looking for Quantum superposition so you know a a particle can exist in more than one States at the same time having more than one energy for example or being in in physically different locations at the same time going around trees like the quantum skia Quantum tunneling again something that physicist and chemists have been very familiar with going back a whole Century Quantum tunneling the idea that particles can sometimes behave like waves uh and a particle can actually pass through an energy barrier a force field a bit like a a ghost or a phantom passing through a solid wall something that if we saw an everyday life we'd be amazed by but that happens all the time in the quantum world I always say it's a bit like um you're having to kick a ball up a hill you have to give it a hard enough kick to get it over the the the brow of the hill over to the other side and if you don't give kick it hard enough it'll roll back down again every time um in the quantum world you can kick it and need only go up halfway up the hill but there's a certain nonzero probability that it will then disappear and reappear on the other side and roll down the other side of the Hill it sounds like magic and you know you when when explained to a non-scientists they tend to think well that you know that sounds silly don't you right go back and and think a bit harder because that surely is impossible but it's what happens and we know that happens in the quantum World in fact Quantum tunneling is the reason we are here because it's the reason the sun shines the process of thermonuclear Fusion that gives the sun its energy its light and heat is because light Atomic nuclei are fusing together to form heavier ones the first step in that in that process Is two hydrogen atoms or rather two hydrogen nuclei protons fusing together but if you remember protons are positively electrically charged and so they will repel each other they can't stick together unless they get close enough together to feel the much stronger What's called unimaginatively the strong nuclear force um but they can't get close enough to to feel the strong nuclear force because of the the electrostatic repulsion between them but because they can Quantum tunnel through this repulsive barrier you can think of one tunneling through the barrier to get close enough to the other um they can get get close enough there's a probability they can get close enough to stick to fuse in this process of nuclear fusion so Quantum tunneling is something we know a lot about it was the earliest ideas of quantum tunneling came about in understanding radioactive decay how a radioactive nucleus can spit out an alpha particle the alpha particle also has to overcome an energy barrier so there's a certain probability that it can can escape okay uh and then quantum entanglement now quantum entanglement is one of these weird uh what it's been regarded as a weird mechanism famously you may have heard that even Einstein didn't like it he called it spooky action at a distance the notion that two separated particles were still still needed to somehow be described as one Quantum system one state which means that if You observe or measure one of the particles somehow that's going to change or affect the properties of the other one well quantum entanglement we're now becoming more familiar with and and and discovering that it's actually possibly one of the most fundamental Notions in quantum mechanics uh entanglement is is something that should be taught at undergraduate level I don't know how many other physicists in physics departments teach ideas about entanglement undergraduate level they're probably still teaching the the basic for the physicist in the audience the onedimensional shring time independent shring equation Square barriers and square Wells and transmission reflection curve boring boring stuff they they don't mention the measurement problem they don't mention quantum entanglement they don't mention decoherence and they blink and well should um right so so these are the non-trivial so so what what what is Trivial then well the trivial quantum mechanics is simply the the the the discreetness of of electron orbitals that that that to give rise to the properties of chemical bonds for example how electrons arrange themselves between atoms when they're bonded together this is somehow somewhat more interesting these effects okay so how did Quantum biology start well actually it it goes all the way back to to the early uh 20th century there were successes in quantum mechanics uh in the 1920s uh but there was also uh an interest in what is called organicism so basically there were two schools of thought in biology back in the turn of the 20th century you had reductionism the idea that something was simply the sum of it its parts you take it apart and you should be able to you know to this building blocks you able to to put it all back together again the other side you had vitalism which was sort of almost a non-scientific idea that somehow there was a spark of Life there was some magic pixie dust you could sprinkle over inanimate matter and endow it with with this this property we call life in the middle was organicism uh the organic organists said there's something mysterious about life that can impr principle be explained but it either requires a a different way of approaching what we currently understand as the laws of physics and chemistry or we may need new laws of physics and chemistry it's not magic right it's not it's not vitalism in any sense but there's something more to life that distinguishes it from inanimate matter and that led to when quantum mechanics uh was developed people started to wonder whether quantum mechanics was that new principle that could be applied and explain life Neil bore F founding father of quantum mechanics I guess uh inspired many people Max Del Brook started off as a nuclear physicist ended up being a molecular biologist um B gave a lecture in 1929 and he says the following before I conclude it will be natural at such a joint meeting of natural scientists to touch upon the question as to what light can be thrown upon the problem B was awful at explaining things very obscure light can be thrown upon the problems regarding living organisms by the latest developments of our knowledge of atomic phenomena by which it means quantum theory which I have here described basically he said saying can we learn something about what makes Life Special by using some of the ideas from quantum mechanics he was just throwing it out there for people to think about and some physicists took that up uh one in particular was Pascal Jordan um not one of the people that you know we tend to remember as the founding fathers of quantum mechanics you know think think of if you've seen the film Oppenheimer and and the list of of of of great physicists who are working uh uh working on the Manhattan Project you know there's you know and even those who aren't there you know we we know of Schrodinger and Heisenberg and poy and dur and fery Pascal Jordan well he published a paper uh in 1925 with Max Bourne in Germany in gingham uh and then they were joined by the young genius Vera Heisenberg so these two papers on quantum mechanics or what became known as Matrix mechanics essentially laid the mathematical foundations for quantum mechanics in the 1920s I I show these to to emphasize Jordan's quality as as a as a physicist playing with the big boys well it was Jordan who arguably published the first paper on Quantum biology he he um B had come had developed this idea of indeterminism and complimentarity ideas almost relating to Easter mysticism Jordan wanted to apply some of B's ideas inside living systems to try and explain what's special about life um you'd think that uh therefore uh he would be uh renowned uh and goes down in history as as the founding father of quantum biology going back to the early 1930s there was however a rather serious problem Jordan was a Nazi and I don't mean that I'm keeping my head down not saying anything sort of Nazi in Germany in 1930s know he was a fully paid up fascist uh and and he tried to to incorporate some of the ideas from from quantum mechanics into his political ideology as well and vice versa and so of course after the war he was completely discredited and with him to some extent went Quantum biology because he some he was the sort of the the flag waver for Quantum biology Quantum biology as a field had nothing to to be ashamed of it's not like Eugenics right you it's it it was a serious attemp attt to try and look at whether Quantum effects play a role in biology but of course it lay dormant for a while well almost because another uh one of the founding fathers of quantum mechanics was irn Schrodinger and he wrote this famous book what is life in 1944 and in it he says this the living organism seems to be a macroscopic system so you know not Quantum but large in terms of its complexity size um which in part of Its Behavior approaches purely mechanical as contrasted to thermodynamical behavior to which all systems tend as the temperature approaches the absolute zero and the molecular disorder is removed basically what he's saying is that there are certain materials that if you cool them down to near absolute zero right um Z 0 degrees Kelvin minus 273° C uh just a few degrees above absolute zero certain Quantum effects can kick in super conductivity super fluidity what's happening is that we because it's getting so cold we're calming down the thermodynamic chaos and and movements and vibrations of the molecules and atoms that that make up uh that material structure so when you calm them down these delicate Quantum effects can then kick in they don't get washed out by thermodynamics and Shia was saying the the order the structure inside living systems is reminiscent of inanimate matter near absolute zero where Quantum effects play a role so do Quantum effects play a role in the the structure and Order of uh uh life so the point is can like you know we are in some sense like steam engines you know we we we need energy what we call useful low entropy energy uh as food like you you shovel coal into a steam Eng and that coal is turned into useful work steam engine can move well we also need food and metabolize it and that gives us energy to live and to maintain our living State we don't have the fuel we die but we're more than that and so you know Shing us point was can light life somehow sort of reach down Beyond ther the thermodynamic chaos down to the the the discreetness the order the structure of the quantum World well nothing much happened after in us but I mean admittedly what his life was incredibly influential Crick and Watson both um stated that they found it very inspirational in their research um but nothing much happened uh really for the several decades um well this it happened slightly before this came out but this is a the front cover of the the journal Nature uh it uh depicts what became the the uh poster child of quantum biology this the bird the European Robin it's an article by the science writer Phil ball in 2011 the the the idea of the Robin is that it's it's one of the creatures that we know uh H has something called Magneto reception it can sense the Earth's magnetic field we know that there are lots of animals that can do that including insects and and you know the monarch butterfly and so on but it's a European Robin that got picked up a and uh and studied carefully and linked with quantum mechanics uh it was studied by an Ornithology uh husband and wife team they published their their their their work in the journal science in the 1970s what they would do would be they knew the European Robin so unlike the British Robin which is sedentary which stays on thees all year round the European Robin that spends its spring and summer up in northern Europe in Scandinavia migrates every Autumn down to the Mediterranean and as we we know with migratory birds and marine mammals they have lots of tricks that allow them to find their way whether it's having a map of the the stars or or or following a sense of smell or whatever well the European Robin also uses this Magneto reception it can sense the Earth's magnetic field a very weak magnetic field how can how can that influence a living organism well they they confirm that it does they would capture these birds in mid- migration stick them in these funnel like Chambers with um a sponge with ink at the bottom so when the bird is is down on the base of the funnel it gets his feet covered in ink and then blotting paper around the sides so as it tries to escape from this this trap it automatically tries to continue its migratory journey in the right direction and so you'll see uh uh you many more Footprints in One Direction on one side of this funnel aimed down towards the direction of it that it wants to fly down to the Mediterranean they can then put magnetic fields around this these these traps something called Helm Holtz coils that can have the same uh magnetic field strength but opposite polarity to the Earth's so they cancel out the Earth's magnetic field so the birds don't sense any magnetic field and they fly around in all directions and you see sort of footprints all all around evenly so anyway that was beyond sort of doubt but what was uh the the mystery was where is this chemical compass and by the uh sort of by the time that Phil ball wrote his article in nature the leading theory and to this date it's the only uh Theory we have doesn't mean it's it's correct but it's the only Theory we have uh is that well first we know that this Magneto reception is activated by the bird's Eyes by their retina photons coming into the eyes uh the theory suggest there is a uh a photosensitive uh protein a molecule inside the retina called cryptochrome and the photon that comes in knocks one of a pair of electrons in one of the atoms in this protein remember protein molecules are large many many atoms the photon knocks one electron these electrons are quantum entangled right so one spinning up one spinning down let's say it knocks one off the atom so that it then flies off and sits on an adjacent atom some by atomic distances quite far away but these two electrons for a certain period of time remain Quantum entangled so what one does the other one also senses and the way they spin whe they spinning clockwise or anticlockwise in which are terms that we shouldn't really use in quantum mechanics but that's that's sort of the plain plain language trying to describe this nature or what Quantum spin is but let's say spinning clockwise and anticlockwise um the way they spin the way they dance is very delicately uh uh uh influenced by the Earth's weak magnetic field acting on on the bird as a whole and so the direction of the bird changes the way these electrons are spinning spin up or spin down and that will send signals to the bird's brain telling it what direction to go so it's it's it's fascinating because quantum entanglement Einstein's spooky action at a distance many would argue the weirdest feature of all the caner intuitive features in the quantum world is responsible for helping the European Robin find its way uh down to the Mediterranean for you it's it's it's it's nice it's it's a it's a lovely story doesn't make it correct right so Quantum biology is still to this day rather speculative well I got involved interested in it back in the late ' 90s back in 1997 a colleague of mine John Joe mcfaden who's a molecular biologist came gave a seminar in the physics he's also based at sorry he gave a seminar in the physics department where he was suggesting that a particular biological process something called adaptive mutations which was puzzling biologists at the time might have a Quantum explanation I won't go into the details but he basically gave the talk and most of my physicist colleagues just found it silly it was this biologist coming and telling us about quantum mechanics I I was intrigued and and you know went for beer with John Joe Afters and we talked about it and and since that time for many years he and I would just dabble you know we would would follow the literature such that it was uh but people suggesting Quantum effects in life we would talk to other physicists who also had an interest in this in this field people like um Paul Davies who's now based in Arizona in the US I think back then he was still in Australia uh another theoretical physicist um but anyway by by 2015 Jon Joe there he is he and I published what I'm I'm proud to say is still the only Popular Science book on Quantum biology um in it we started off with more established mechanisms in biology and gradually got more speculative by the time we get to the end of the book we you know there there's you know huge warning signs as to you know please let's not uh say that quantum mechanics is going to cure cancer because the daily male would love uh you know or the quantum mechanics is you the origin of Life of D quantum mechanics but there were certain um more specific example even more established than the the the European Robins Magneto reception we we certainly got a we got a grant and we set up a um a a doctoral Training Center at s that's the 20 20 plus PhD student ships that's the first cohort um I'm pleased to say that my my three PhD students have all graduated gone on to greater things um so we started to take it seriously is what I wanted to to get across and um examining particular areas of quantum biology where we could make some progress walk before you can run you see the problem is that Quantum biology is still speculative still controversial physicists don't like studying the the physical processes inside living systems because living systems are complicated a physicist likes if they're doing an experiment they want to do it in a lab where they can do it in the absolute zero in a vacuum shielded from its surroundings you know spherical cows in a vacuum is the famous example where you can tweak dials and you can control things you can't do that in a living cell you can't turn off certain chemical reactions and only look at a particular process so no thank you biologists didn't like it because they didn't tend to study quantum mechanics quantum mechanics what a load of nonsense not in my lab thank you and then the chemists who sit in the middle say well you know all biology is chemistry in the end and all chemistry is atoms and molecules of course it's quantum mechanics don't go inventing names for new Fields just to get more funding you know what's what's what's the big deal and so you could see there were arguments from from all lots of which for me is great because it means the field remains small and Niche and and you know one can make a name for oneself without having to you know imagine you know in in in fields and saying high energy physics for example where you know lots of people are working in it you know you you are just a small Cog you a very big machine here you can you know you can publish the papers that become you know the the key papers in this field um so candidates for Quantum effects what were we looking at well uh I'll I'll give you a list so first of all uh enzyme action was something that was confirmed so enzymes are the workhorses of of the cell uh they catalyze chemical reactions they speed them up dramatically and one of the tricks in their Armory that was discovered back in the 1980s very sort of key research at Berkeley was that the way enzymes make and break the molecules of Life they build proteins they dismantle uh uh molecules one of their tricks is to use quantum tunneling to move particles from A to B because it's a more efficient way of getting them from A to B if they don't have enough energy they can Quantum tunnel through so Quantum effects were discovered inside um enzymes and that's not really controversial photosynthesis well I say well established uh probably not so well established yet so photosynthesis one of the most important uh uh processes in life plants and bacteria capturing sunlight and and and delivering it to the reaction Center in the cell converting it into chemical energy to build biomass right that we then eat so sustaining life the first stage in photosynthesis is delivering that lump of energy that lump of sunlight the photon to the reaction Center and if you only apply classical mechanics it would appear as though that Photon would bounce around like a pinball a ball in a pinball machine randomly and more than likely then just lost as waste heat and yet with almost 100% efficiency for this stage of photosynthesis that Photon arrives at the right place and the theory that suggests it might the way it does that is through this idea of um superposition and interference the the the ski are going both sides around around the tree in this sense in this case the the photon excites electrons in the in the chlorophyll molecules what are called exons and those can have a a spread out effect over the whole cell and only with quantum mechanics are we able to explain its efficiency but there are still those who argue that it can all be explained using just vibrations just classical uh uh me mechanisms that don't need any quantumness Magneto reception Birds I talked about how we smell the the the the again something that relies on on Quantum tunneling um again still speculative and I don't really have time to go into it because I want to talk about point five DNA mutations which is our work at Sor there are other more speculative ideas of course where quantum mechanics plays a role in life I mentioned connection with cancer connection with the origin of life and then of course something that that Roger Penrose of course has been uh associated with for a number of years the connection with the nature of Consciousness six seven and eight are are are regarded as we are not ready to to say something definitive about them until we can establish Quantum biology uh in in the the earlier points so I want to talk about DNA tunneling it goes back to uh uh work by Swedish uh physicist per ol of line uh who said that uh the the DNA uh double helix so think of the DNA as a as a twisted ladder the the rungs of the ladder are hydrogen bonds they're chemical bonds which essentially are hydrogen atoms or for me as a nuclear physicist they're protons I don't care about electrons I'll leave those to the chemists the hydrogen bond is a proton right and that proton can jump from one strand of DNA to the other he suggested uh he he talks about this new field of quantum biology suggesting that maybe proton tunneling might be a a way that these protons get from one strand to the other not just by being knocked off by a a passing water molecule as you might think will be more sensible so anyway so we start to look at this look at this in more detail using computer simulations so here you have your double helix strand DNA if you zoom in remember the the the alphabet of life you have four what are called nucleotides adenine thyine guanine and cytosine guanine and cytosine always bond together Adine and thyine bond together and you can see ad and thyine here that these dotted lines these Dash lines are the hydrogen bonds the protons and those protons tend to like to sit closer to one strand than the other you can almost think of them like a spring that can bounce between the the two so uh those the protons are the little white balls and they can jump so the blue is nitrogen and then the red is oxygen so they can jump across to the other side uh was something was established experimentally and this is I'm showing here what essentially the the what I was poo pooing as the balls and sticks models of biology I mean that my PhD student Adam godb assured me was was generated using a huge uh uh uh computer code using something called density functional Theory uh and just because it looks simplistic actually to get that that the jumping and the probability they jump was was a a major uh calculation what is it that's happening how does it get across well of course we could imagine that there's the Proto so this is remember the ball kicking the ball up the hill this what's called a double well potential think of it like an energy like potential energy uh uh you know how much you know the higher up you are the more energy you have so the ball needs to have high enough energy to get over that bump in the middle to get to the other side to the other strand of DNA and it can jump over the top uh if it's kicked hard enough but you can go halfway up and then just Quantum tunnel through to the other side so what we wanted to address first of all is uh How likely is it to happen and secondly How likely is it to happen through Quantum tunneling and not just over the barrier hopping um so okay so I'm now getting a bit technical so that's why I can speed up because for many of you might might might not mean too much uh there are two steps in in our calculation one is to to plot what's called that energy surface that that double hump that the hump with the the the two wells in it to get the right shape is absolutely vital uh and we use various techniques in quantum chemistry uh uh this was based on work back in 2021 and you can see that right so this is a remember at are held together by two hydrogen bonds G and C are held together by three but only two of them jump across um Kick imagine kicking the ball up don't worry about the these points are not meant to S traces of the ball they're just the the points where the calculation has given us a number and then we've joined the dots to give us the shape of the energy surface and so when the the proton is over here you know that this proton's on this side this on this side you give it enough of a kick it goes up to the top but that Plateau doesn't look like it's a very stable place for the proton it could easily just roll back down again so at wasn't seen as a good candidate for for for this transfer proton transfer but G and C look if it if it gets up to the top of the hill and goes down to the other side it could stay there for longer or it could Quantum tunnel through through the barrier and what we found was that this was a very likely thing to happen how do we work out how it happen so we've got the energy we got the shape step two is is that's my bit the quantum mechanics calculation the point that when we learn about quantum mechanics at University at undergraduate level we tend to apply it to what are called isolated systems the shringer equations the famous equation that describes how atoms electrons protons move around and interact only works when that system is separated from the outside world we learn that how when it interacts with the outside world that's called a measurement you're looking at it or the outside world is causing it to what's called decohere but inside a living cell you can't treat anything as isolated so you have to use what's called an open Quantum system approach you surround your system by an environment and essentially the environment is looking at the system it's constantly measuring it constantly interacting with it another way of saying it is that the quantum system is leaking its quantumness out into its environment for for the the technically minded uh what we solve is is a master equation is a famous one called the Ciera Le uh model it's it's it's there are more sophisticated approaches but that that fitted our purposes for now uh so what we were doing was essentially cranking the handle for this equation to see how that proton travels through the barrier or over the barrier so we found there's a there's a very large probability the toric occupation means the chance the proton on the other side for G and C one in 10,000 times if you were to look at just a pair of these bases and you could take a photo of them 10,000 times 10,000 snapshots one of those snapshots the proton will be on the wrong side that's a lot um and also the fact that uh so this is a plot against temperature right so so this this vertical line is the the temperature of of living systems around about 300 Kelvin and you can see the if you only allow the protons to go over the barrier then you've got like one in a ion chance uh that that it'll get to the other side but if you allow Quantum tunneling then most of this 1 in 10 to the four is down to Quantum tunneling and so it's very likely to happen now I what I didn't mention is why is this at all interesting well this goes back to L Dean's paper in the 60s because he said DNA the pro the hydrogen bonds the protons can jump from one side to the other so what and they might jump back again you know when if they don't like what you know life on the other side um but DNA gets unzipped in the process of replication it enters a particular enzyme system called a helicase and that helicase it's like a zip Fastener being unzipped and the two strands are separated if they're separated and that proton or the both the protons because one moves the other moves if they're in the wrong position then in the process of replication a will not bond to T and T will not bond to a they will bond to a different base what this means is a mutation okay so if the proton's in the wrong place that can lead to a mutation so it's very interesting to and even Crick and Watson um thought about this idea maybe you know if a proton can transfer from one suround a to the other in a hydrogen bond that could lead to a mutation now clearly we know how often uh mutations take place we know that mutations are very important because without them life wouldn't be able to evolve we also know they can be very dangerous because we don't want the Corona virus us to to mutate away from something that you know our our drugs can attack um but we and we know mutation can take place in all sorts of ways ionizing radiation copying errors you know there's lots of mechanisms this is another one proton tunneling and it seems to be far more than we see so what's happening one thing to say is that we have an open system and so the the uh the the the surrounding environment inside the cell is causing decoherence the water uh molecules that the the this the DNA is floating in they're constantly observing the system causing it to decohere but it doesn't completely decohere you can plot how to what extent your quantumness has disappeared has dissipated to what extent has it decohered and the information has moved out there's a measure uh in quantum mechanics called the volman entropy which is a which is a a number that we can calculate that tells us how much quantumness is left in the system uh and what we find is that actually although if you ramp up the temperature for uh the temperature this is the temperature of the water surrounding the the the molecule right the environment's temperature the bath if you ramp out the temperature then the VOR entropy goes up the disorder goes up and and and and quantumness disappears and decoherence sets in but at the at uh living temperatures 300 Kelvin there is still quantumness there is still Quantum tunneling taking place what's interesting then is what happens when you unzip the DNA uh and uh what we found was that so clearly here uh when the when the DNA is at thermal equilibrium and not being unzipped and it's just quite happily mining its own business uh this is what the potential energy surface looks like there's a one in 10,000 chance the proton will be on the wrong side fine but what happens when they unzip because of course as they separate that it becomes increasingly harder for the proton to jump across that the the two strands are further and further apart the energy needed is is higher the barrier gets higher do you trap the proton in the in in that place uh that you want or um you know does it roll back again what we found in fact that something very clever seems to be taking place inside this the helay system there's a particular uh enzyme called asparagine which sits it does the unzipping it sits right at the entrance right at the the point where the two strands start to separate and what it does is change the shape of the the the potential energy that the the proton is feeling so this dip here disappears what happens then is that most of the protons that were in the wrong place the one in 10,000 which is still you a large fraction roll back down to the original position and so the question became we were Wonder wondering whether life has the ability to uh uh use quantum mechanics to its Advantage can it you know in enzymes it uses proton tunneling uh enzymes use proton tunneling to their advantage and one can argue that life has had four billion years nearly and it's evolved the ability just just through random selection processes to make use of quantum me why wouldn't it you know if if if it finds a way of making some process more efficient whether it's classical mechanics or quantum mechanics life will use it what we're finding here is that it seems that life knows that quantum mechanics would cause a lot of mutations uh and so those the those the organisms where where lots of mutations were taking place du of quantum tunneling oh clearly they didn't survive they didn't do very well but those that had this enzyme here that changes the rate of mutation CH rate of toriz those are the ones that survive so life knows about quantum mechanics and it mitigates against its worst uh um excesses um I'm I'm going to do really something really awful here because I know I don't want to go over I want give you time for questions I'm going to skip over uh the measurement problem quum mechanics essentially the measurement you know Thro us cat in the box and there are there are um different aspects of the measurement problem the first two are solved by decoherence the third one the problem out outcome requires an interpretation of quantum mechanics so for example just two two of the you know the more popular interpretation of quantum mechanics spontaneous collapse models uh would say that the cat is it's not that when decoherence takes place the the cat is is either dead or alive and it's just our ignorance no both the dead and alive sis um situations are there it's the cat dead and alive at the same time that's got decohered away uh but you need an interpretation to choose one outcome uh and spontaneous collapse models would say uh one of them disappears and the other remains uh uh an everettian many worlds interpretation will say that neither disappear you just find yourself in one universe or the other without a dead cat or Alive cat but the point is that uh uh the the what's happening inside the the helay seems to be a bit like shringer cat in the Box you've got uh your your water molecules which is the environment which causes partial decoherence so you can think of the proton being in both situ both positions at the same time were more likely as of some spread out wave function smeared out across the whole uh Bond but then as the strands separate the helicase is the Observer the helay is is is Shing opening the box or more correctly actually the cat because the cat knows if it's dead or alive right it's not you don't need someone to open the box to tell it it's the cat's perfectly capable of causing decoherence very macroscopically distinguishable States okay so here is the hel that not only uh makes the measurement but it also adjusts things it makes sure that the proton isn't in the wrong place most most of them are are in in the right place and then it does the measuring okay so the conclusion is that when it comes to Quantum tunneling DNA it's not that life uses quantum mechanics to its Advantage but it knows about quantum mechanics and has evolved mechanisms to prevent things happening uh uh would damage damage life so does life use quantum mechanics I would argue yes we are starting to see evidence for it and we also starting to see evidence that life if it doesn't do something about you know things the quantum mechanics can be can be damaging as well either way life seems to evolve the ability to to to use some of these trickery of the quantum world and I will end there by thanking my my collaborate maros saki is a computational chemist that I work with at Sor Max swen's my PhD student he's just submitted his thesis Lis slom's a x PhD student who's now a postto working with us we we get our claws into the the the smart guys and we don't let them escape and I think I should end there because I've now talked for to three minutes past six and I was hoping we'd have time for just a few questions so thank you very much for your [Applause] attention