Quantum Biology | Explained by Jim Al-Khalili

if I were to define quantum biology I'd say it's not what many people might think that at the very deepest level if you look into a living system a living cell down to that level of molecules and atoms then you hit the quantum world because that will be true for life as well as for inanimate matter where the quantum rules kick in now quantum biology as we define it today means exploring the mechanisms of phenomena that rely on non-trivial quantum effects within living cells by non-trivial I mean quantum tunneling long-lived quantum coherence and superposition quantum entanglement evening these are surprising effects that we're now seeing taking place within living organisms that is quantum biology we tend to think about quantum biology as being quite a new area of interdisciplinary science and in many ways it is but actually it has rather old origins going all the way back to the early 1930s in fact we can even trace it back to a particular lecture that Niels Bohr gave at a conference in 1929 he hinted at the idea as many of the quantum pioneers were doing back then that maybe quantum mechanics holds the key to so much of science and the fact that quantum mechanics in their opinion solve the problems of physics and chemistry they arrogantly then assumed that it could also be used to tackle the mystery of life itself and so Bohr was one of these early console pioneers who suggested maybe quantum mechanics could play a role and he inspired other physicists particularly people like max delbruck who then actually them changed field and became a biophysicist working molecular algae and also Pascal Jordan now Jordan is most famous because he was one of the authors on the classic papers on quantum mechanics on matrix mechanics with Max born and Verna Heisenberg in getting him Jordan I guess is lesser known than born and Heisenberg but he's certainly one of the the names of the the quantum pioneers of the 1920s Jordan really in a sense was the founder of of the field of quantum biology he was looking for rules from the quantum world such as in determinism complementarity ideas that he had developed by studying on the ball and whether they applied and played a vital role in life in fact Pascal Jordan probably published the very first paper on quantum biology back in 1932 advocating some of his ideas about how quantum mechanics and the act of observation and so on lead to the phenomena of life which were still in some sense mysterious the problem of course is Pascal Jordans political views were rather unpleasant he was a Nazi and he wasn't just one of those people in 1930s Germany who kept their head down who maybe didn't speak out against the government no he was a fully paid-up fascist and so after the war with his reputation of course in Rouen quantum biology also in some sense was tainted by the shadow of being championed by it by Pascal Jordan however there were others who still believed there was something in this idea that quantum mechanics could play a role in explaining life so in the early 1930s the the Cambridge theoretical biology Club was formed and it contained many of the some of the greatest thinkers in Cambridge of that day even people like the great evolutionary biologist JBS Haldane many philosophers many mathematicians as well as physicists and biologists the Cambridge theoretical biology club essentially I think they advocated a view which would call Organa sysm now the organicist s– were sort of halfway between two other rather extreme schools of thought which they believe were wrong when it came to describing life on the one hand you had the mechanistically reductionist view of life the living systems yes they were highly ordered yes they maintained low entropy but essentially we're steam engines you give us energy we use that useful low entropy energy to maintain the order within the systems of life so that was the mechanistically you on the other extreme was vitalism now the vitalist had been discredited by the 20th century really because they believed there was some magical spark they endowed life with whatever makes life special that differentiates between living and nonliving matter so the organicist said no there's something more to life than just sort of machines we are weird you can't get to understand it with what we currently know building on sort of Newtonian laws for example but on the other hand there is this they argued something special about life maybe presumably some as yet undiscovered or not particularly well understood laws of physics and chemistry that are required to explain biology if I were pushed I'd say in some sense that that is what most quantum biologists or certainly those physicists chemists biologists spectroscopy us who work in quantum biology there is really no such thing as a quantum biologist this is what they would argue today there are sir laws of physics or chemistry as yet to be understood that would have would need be needed to explain laying life of course that group in Cambridge in 1930s there were others certainly for example among the quantum pioneers Owen Schrodinger should really be mentioned because he published a very famous book called what is life in 1944 in which he proposed that maybe the the order of of living systems is akin to inanimate matter at very low temperature we know that when you drop down to near absolute zero quantum effects kick in like super conductivity or super fluidity when the thermodynamic random agitation of atoms and molecules can be calmed down and you allow for quantum effects to to persist we see that in inanimate matter at low temperature Schrodinger was advocating that maybe living matter with its low entropy highly ordered state is akin to inanimate matter at low temperature therefore it also is the way it is because of quantum effects in quantum phenomena he talked about a periodic crystals which of course then with that's what DNA is essentially it's an aperiodic crystal so the the basic fundamental building blocks of life do somehow have a requirement to be explained by by laws of physics and in particular quantum physics the one thing that we have to remember is that quantum mechanics and then developing into quantum field theory and so on was developing in parallel with the new areas of biology genetics and molecular biology and the geneticists and molecular biologists by the 1930s 1940s and indeed 1950s when double helix structure was discovered really felt they had no need for quantum mechanics they were they were so successful they were learning so much about the molecular structure within living systems that they saw no requirement to bring in the strangeness of quantum mechanics so to a large extent quantum biology really went into abeyance it it sort of went into the background particularly after the discovery of a double helix of DNA spectroscopy molecular biologists really were learning so much more about the the building blocks of of of of the cell the the the instruction manual of life they had no room for quantum superpositions and the measurement problem and the uncertainty principle and all all that silly business they leave that to that to the at the same time physicists had their hands full you know we we've we've also been very successful in the 20th century from from quantum mechanics comes quantum field theory nuclear and particle physics develop we learn about the building blocks of matter on the theoretical side we started looking at how we unify the different ideas the different forces of nature quantum field theory itself then evolved into quantum electrodynamics quantum chromodynamics by the 1960s and 70s we're building bigger and bigger accelerators to look at smaller and smaller constituents of matter physicists didn't want to go and look at the messy world of biology biologists didn't have the quantum mechanical background to apply some of this hard math to to to to to the processes of life so until all the way through several decades probably until the 1990s very little was done quantum biology was seen as a as an outside a rather controversial somewhat wacky area of science particular particularly when you think about some of the ideas that grew up during the ninety sick little late 60s and early 70s or when people were using quantum mechanics to describe all sorts of strange phenomena such as telepathy or ideas in pseudoscience that you know quantum mechanics developed this mystical arm one of the most famous examples was the work of Roger Penrose and Stuart Hameroff they proposed a mechanism that they argued explained the nature of consciousness and and and the idea that there were these these proteins within the the neurons of the brain that could exist in a quantum superposition or two configurations and when enough of them became entangled together that's when consciousness switched on there were some brief excitement about this idea initially but I think very quickly most scientists said no hang on a minute just because quantum mechanics is mysterious and we don't understand it call an and consciousnesses misters to understand it does not mean that the two have to be connected and so that was another reason why people were rather nervous about approaching some of the ideas in quantum biology that changed in the 1990s suddenly there were experimental techniques using fast pulsed lasers 2d spectroscopy it was called where you could pump biomolecules excite them and see how they decay and suddenly some of these experiments was were beginning to show that there were quantum effects going on long lived coherence long lived interference effects that you couldn't explain otherwise think of the famous two slit experiments in quantum mechanics firing a beam of particles where the photons or electrons or whatever through the two slits and you see the interference pattern you can't express even when you fire them one at a time you can't explain that interference pattern using classical mechanics you need quantum mechanics what they were seeing the equivalent of that taking place in certain special mechanisms within living cells for example the way enzymes transfer particles from one part of a molecule to another electrons and later even protons 2,000 times more massive electron they were seeing these protons quantum tunnel from one place to it to another I became interested in this field of quantum biology in the late 90s but only as a hobby and I wasn't taking it seriously my background is is nuclear theoretical nuclear physics so I've spent my career modeling nuclear reactions quantum scattering theories where we can compare with experiments and and we can develop and advance our theories but John John McFadden who's a molecular biologist colleague of mine here at the University of Surrey this was in 1997 he came to the physics department and he gave a seminar on an idea that he had and he said quite he admitted that this was probably a wacky idea there's a certain type of mutation called adaptive mutations in which for example bacteria e.coli in in this case that he was looking at had the option of of mutating in one direction or another and without any help from the surrounding environment that should be random 50:50 but if their surrounding environment contained in this case glucose sort of energy the one of those mutated states could take advantage of but the other couldn't suddenly you saw more mutations going towards the the side that could utilize that the the the the food in its environment and this was a puzzle you know how how it had to can it know in advance before it mutates it doesn't know that there's glucose in the environment so and so all I found mutate this way I can I can feed and multiply and and and make many copies of myself but if I go the other direction I can't utilize the glucose and I'll die the idea that John J McFadden had was that somehow the the some biomolecule within the the the e.coli bacteria could exist in a superposition of two states or the genetic mutation could exist in superposition of two states and it maintained that superposition until the time when it could again be measured by its environment when it decays it'll happen in two different ways it was a very hand wavy idea and essentially most of the physics department here a sorry who listened to his talk dismissed his ideas out of hand partly because it was crazy and partly because he was a biologist trying to tell us physicists about quantum mechanics I was intrigued enough that I spoke to John Joe about this afterwards and thereafter began a collaboration that has now lasted over two decades between us in which we've looked at ideas of quantum mechanics in in biology and as we our interest has grown so has the field of quantum biology other example have been discovered still controversial still you know open to be dismissed as wrong but nevertheless examples and published in top papers like science and nature which suggests that something quantum mechanical is going on inside living cells whether it's in photosynthesis whether it's in enzyme catalysis whether it's in mutations of DNA even more controversially I the way we smell that the theories of olfaction or magnetoreception the way certain animals can sense the Earth's magnetic field that their chemical compass that allows them to detect orientation of the field relies on quantum effects quantum entanglement of 2 to 2 electrons so these are controversial ideas they're speculative but they're they're hugely exciting and we have yet to to know for sure whether whether or not this is going to lead to something for me as a theoretical physicist what's exciting is that it's allowed me to move into this new field open quantum systems the idea that you when you're solving a problem quantum mechanics you no longer just solve the Schrodinger equation because your quantum system of if interest is surrounded by an environment that plays a very important role and that's why people are skeptical about quantum biology so how can these delicate ephemeral short-lived quantum effects have any functional role at all in biology given that they are existing within an environment that is warm complex messy surely decoherence kicks in with in femtoseconds but to play a biologically significant role they have to last for pekoe or nanoseconds or even even longer and yet it's sir it seems there are hints there in that life has evolved the ability to maintain these quantum effects for long biologically significant periods of time the noise of the environment that measures the system that causes it to dica here or today we talk about a quantum system becoming increasingly entangled with its surrounding environment rather than killing off quantum effects it seems to be resonating with it seems to be maintaining it there seems with different kinds of noise that we have to now consider so on a theoretical from a theoretical point of view this is a hugely exciting area its borders on questions like the what is the measurement problem the questions about in the foundations of quantum mechanics studying some of these phenomena and quantum biology of course is more than just intellectual curiosity if we think about some of the big areas that are funded in research today particularly here in the UK I can think of two one is quantum technologies the idea of utilizing some of the non-trivial quantum mechanics to develop new instruments and new and new techniques and and and so on new sensors a lot of money's going to quantum technologies has nothing to do with biology on the other hand you have synthetic biology developing machines that rely on the machinery of life quantum biology somehow is the bridge I argue between synthetic biology and quantum technologies if some of these mechanisms that we're now seeing in in living systems like a quant long live coherence and photosynthesis like quantum tunneling in DNA if they turn out to be true and this it's not magic you know life has had nearly four billion years to perfect all his trickery if utilizing the rules of the quantum world gave life and advantage over classical rules it would have used them so therefore can we learn if life has figured out some of these tricks can we learn from life and develop our own ideas that will this have a bearing on the work in in developing quantum computers will it have a bearing on work developing new quantum magnetic sensors so there are all sorts of technologies that might be advanced maybe developing new types of photovoltaic cells and certainly to develop solar power if if plants and bacteria in their photosynthesis have used a very clever trick from the quantum world maybe we can copy that to help our advances in our technologies now here at sari we finally John Joe and I have finally become very serious about quantum biology and we now have a center a doctoral training center funded by the Leverhulme trust which is a charity to take on PhD students and we now have an interdisciplinary group containing theoretical physicists computational chemists molecular biologists and geneticists all working together bringing together people from across the university in different fields looking at different aspects of quantum biology it may end up really not being anything but I thought for me it's such an important question and the nature of life is still mysterious enough that I think it's too important not to look at seriously [Music]

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