the fact that quantum entanglement Einstein's spooky action helps the European Robin navigate its way down to warmer climates every fall has a Certain Romance to it um so I I I would like this to be the correct theory of course liking something wanting it to be the correct Theory doesn't mean it's the correct Theory but but it it it it's a fun interesting application of one of the the the weirder features of the quantum World quantum entanglement playing an important role in a in a living living animal helping it find its way hello this is Robinson nhart here with pins podcast and the introduction to Robinson's podcast number 185 in this episode is with Jim alkal who is University of Sur distinguished chair in physics and University chair in the public engagement in science and Jim is a theoretical physicist lots of work in physics he's a an author with lots of books and a broadcaster with lots of documentaries and in this episode we talk all about the fundamentals of quantum biology is that's his current project and what his group is working on at the University of Siri we talk about just what Quantum biology is since if the world is quantum mechanical then biology must be too we talk about how some animals like the robin which is my namesake might take advantage of quantum mechanics how exotic phenomena some exotic phenomena like Quantum tunneling decoherence might fit into the biological world how quantum mechanics relates to the numerous arrows of time and then we also get into Jim's personal favorite interpretation of quantum mechanics because it's pretty hard to have a conversation about qm without talking about the interpretations and Theory as well Jim's latest book is the joy of Science and there's a link to that in the description I will also mention the patreon if you would like to support the show that is a great way to do it Beyond leaving reviews subscribing comments that sort of thing after four patreon episodes now or episodes since the patreon has been up I've decided to jettison for the time being transcript since people don't seem to be that interested in them and they take a lot of work just to do poorly so there is a link to adree episodes and then show notes now without any further Ado I hope you enjoyed this conversation as much as I enjoyed having it with [Music] Jim in 2014 you and and John Joe mcfaden published life on the edge which as I understand is the the first popular book on Quantum biology but when we were talking before recording you told me that Quantum biology is also your current project nine nine years later so what's going on at the University of zui right now well we're we're hoping it's becoming sort of a hot bed Cent for research in Quantum biology admittedly a subject that is uh uh still sort of quite Niche and probably speculative and even controversial maybe some would say actually the my collaboration and discussions on whether quantum mechanics plays a role in biology with John Joe mcfaden who's a molecular biologist I'm a theoretical physicist actually goes back to to the late 90s we um the story is that jonjo came to so he's he's based at s uh with me as well but he's in the the life sciences school he came and gave a seminar in the physics department on whether quantum mechanics might you know speculatively play an important functional role in biology and most of my colleagues dismissed it I decided that I'd want to chat to him a bit more about it it sound intriguing and so we've been dabbling with it since then 2014 we published The Popular Science book on it as you say life on the edge still I think the only Popular Science book on Quantum biology but by that point we had started to get a bit more serious so my my background in theoretical physics and nuclear physics was you know I was I was ready to shift my interests and JN Joe likewise uh and so you know we got funding we got grad students uh we' got research grants and and today it's something that I'm actually you know sort of some fraction of my research activity is is looking seriously at uh these these Quantum effects in biology yeah you you mentioned immediately that it's very Niche and I should add that relative to Fields like quantum mechanics which have had time to get into the Zeitgeist it's still quite nent so I think it would behoove us to start out with just some of the basics and sure if we live in a quantum mechanical world then isn't all biology Quantum so what what distinguishes the sorts of problems and approaches in this field for the more familiar dimensions of biology yeah I mean that's that's a good point and and it's something that people s that's the most people's initial reaction you know everything is made of atoms and so if atoms obey the rules of quantum mechanics then of course you know at some point if you dig deep enough life will also obey those rules that's not what's meant by Quantum biology in in in this sense and we have to be careful because this it Treads this um dangerous but you know uh rather controversial uh uh path because as soon as you start talking about quantum mechanics and life you know those who probably haven't studied quantum mechanics very quickly think oh okay so that you so quantum mechanics explaining Consciousness or quantum mechanics you know will explain all sorts of wacky woo woo stuff you know oh it explains telepathy in homeo telepathy is the favorite one because quantum entanglement oh that's why twins can so you sort of have to draw back from that physicists and chemists have been used to Quantum Mechanics we've had almost a century now and and you know we use quantums every day without it we wouldn't have developed much of our modern modern world um biologists have by a large not worried or bothered about quantum mechanics the point about Quantum biology is not that down at the level of the chemical bonds that hold Mo biomolecules together inside living cells must obey some sort of quantized rules yet of course but that's chemistry right and the chemist will say what's all the fuss about it's more that there are there seems to be evidence that there are certain um processes Quantum processes uh that take place inside living cells Quantum tunneling quantum entanglement long lived Quantum coherence that are unexpected right you know because the usual argument is hang on a minute quantum mechanics is you know Quantum effects are ephemeral they're very delicate we work hard to maintain Quantum effects in our physics Laboratories we're trying to build quantum computers that don't you know deah here very very quickly you're telling me inside a hot noisy complex living cell these Quantum effects can play a functional role well it seems like the evidence suggests that yes maybe they do and for me that may not be may turn out to be complete red herring but for me it's so fascinating and so interesting that it's it's a worthwhile thing to do to to to study it carefully to see what the truth is well I actually in a in a relatively just going back to the first thing you said in a relatively recent podcast I just learned that Quantum Bigfoot is a thing so there are there are no limits to which uh Quantum terminology can be applied but yeah it's a worry I mean I I blame a lot of the physicists in the late 60s early 70s who were all high on LSD and all you know they thought you know Quantum weirdness was was became almost like a cult mythical connection with Eastern mysticism uh and and was trying to shake shake that off quantum mechanics is a serious description of the subatomic World um and if life has evolved the ability to maintain Quantum coherence for long enough so that it plays a role such as the sort of work we're doing now looking at proton tunneling in DNA then you know we need to try and model that and study it and Carry Out experiments to test if it's true or not but these are very isolated specific examples where quantum mechanics plays a role it's it's not we're not saying life doesn't exist without quantum mechanics but life may have evolved the ability to use the trickery of the quantum world and why wouldn't it if that gave it an advantage right absolutely I'd like to hold off on the the tunneling the entanglement and coherence which latter phenomenon I understand is quite important to your current work on the Arrow of time just for the moment because first there were some interesting conceptual difficulties that I encountered when I was uh reading your work and preparing for this and I was wondering what some of the technical difficulties are that come with the territory of of blending quantum mechanics and life so I saw that there were mean specific difficulties involving studying Quantum processes in living tissue yes the it's all very well you know theorists like me uh working with computational chemists and and running computer simulations um deciding that we want to look at a simple process so you isolate it you know the spherical cow and a vacuum business um physicists are used to being able to isolate the mechanisms and phenomena they want to do you know we we we want to study you know in in a laboratory you know we will turn things off we will run our experiments near absolute zero in a vacuum we'll Shield it from its surroundings and then you know you tweak dials you you you you you look at one variable at a time you can't do that inside a living cell because there are thousands of biochemical reactions going on so the experimental tests that would verify some of these theoretical predictions and model predictions are subtle and sometimes indirect and I think I think that's why in Quantum biology theory is ahead of experiment um one can study biomolecules using various spectroscopic techniques you know you can look you can use you know sort of a um high pulse lasers uh to to excite these molecules and watch how they Decay and give the light off and there'll be certain signatures and terms of resonant behavior that could tell you something about the quantum nature of these molec ules but it's tough you know it's um it say it's difficult to turn off everything else inside a living cell to isolate the mechanism you're interested in that's that's where the challenge is yeah I mean talking about lasers I recently did an episode with the the Nobel laurate here at Stanford Carl Wyman on his isolation of the Bose Einstein condensate and reducing a cellular cells to temperatures just just above absolute zero they're not gonna function too well at that point yeah I mean the nice thing is of course that you know essentially what got a lot of people interest in the field is um uh Schrodinger's famous book what is life uh written back in 1944 uh small book almost a sort of almost like a popular science book um is certainly was was his ideas influenced Crick and Watson in their um development of the double helix model of DNA but he makes this you know simple statement that sits sticks with me anyway which is that life the the the the order the structure of Life uh of of inside a living cell is reminiscent of inanimate matter of equivalent complexity near absolute zero so you take inanimate matter certain materials you cool them down to you know a few degrees Kelvin or below and they will you are um calming down all the thermodynamic chaos slowing everything down and you start to see Quantum effects superc conductivity super fluid dis kicking in at certain temperatures well Shing was arguing that living systems behave you know in in terms of the low entropy high order the structure uh as though it's normal matter at at low temperature so it may be that we don't need to to cool down living systems down to near absolute zero they are exhibit the sort of structure and behavior anyway that you would see in inanimate matter that's very cold I don't want to jump too far ahead but is this line of reasoning was it influential to you in beginning this work on the era of time and life I mean life somehow uh I mean at least locally seems to counteract entropy to some extent yes I mean I think it's I think a lot of uh physicists and chemists and philosophers you know there is something about the mystery of life that is sort of intangible um but it's fascinating you know that there was a um a recent paper in nature uh um on on what's called assembly theory is is a new idea in chemistry that um sort of works out the likelihood that chemistry can become biology you know what what are what's the probability that you can get complexity emerging from simple uh Building Together simple atoms and molecules and I think the excitement there is that we have to admit we still don't know how chemistry becomes biology you know the the origin of Life despite some people arguing well it's it's a step step-by-step process and it's not you know Fred hil's famous a wind blowing through a junkyard and and creating a jumbo jet out you know just instantaneously it's a it's a slow process but there is still something mysterious about it and I I guess that is part of the attraction you know you do Wonder did quantum mechanics play a role say in Prebiotic chemistry in the origin of life I have no idea if it did or not but that was may have been I I guess in answer to your question one of the factors that maybe got me excited in the first place even if we've Now sort of pulled back a bit and just and trying to look at it more soberly and carefully mhm yeah that that's interesting I never thought of it that way like I'm sure many people I first encountered I mean the the problem of how life emerges from raw materials in Dawkins uh selfish Gene and as I recall his description of Life emerging from the p primordial ooze or soup it's really maybe it's kind of like a mechanical thing and I'm using mechanical and distinct from quantum mechanical so it's interesting to think that quantum mechanical phenomena might have played a role there I think we know now that it's it's more than just stick all the ingredients in in a in In Darwin's warm Pond or in a the famous Miller URI 1950s experiment you know uh organic materials um water sunlight the spark of life will you know would emerge uh the likelihood of that happening is still hugely hugely tiny uh and so there's still something missing getting us to a complex enough system that is able to replicate itself once it does Darwin and evolution kicks in and you're you know you're well on your way but it's how do you get there in the first place well now that we've set some context but before we get to the era of time I think that Quantum biology as we already mentioned is going to be very unfamiliar to our listeners it wasn't something that i' thought much about at all before this so I thought it would be a good idea to talk about a few examples and the first that comes to my mind is uh it's actually what you bring what you begin life on the edge with is is my namesake the Robin and from the outside these birds I mean certainly seem to inhabit the the classical world that we do but where do Quantum processes come into shape their observable Behavior this has become sort of the poster child of quantum biology it's so fascinating yeah um so the European Robin uh which essentially lives it's you know spring and summer up in northern Europe Scandinavia Sweden uh Russia and every fall it will migrate down to the Mediterranean Ian looking for warmer weather um as many animals marine mammals birds insects do uh in a similar way that for example monarch butterflies will migrate every year from Northeast Canada Eastern Canada down down to Mexico um in the 1970s it was established that the European Robin that was I think the first uh uh creature that that uh was confirmed to have this ability that it was able to utilize among the many tricks that migrating animals used to to navigate it was able to sense the Earth's magnetic field the the the uh angle of inclination of the magnetic field so if you think about the Earth as a giant dipole magnet uh the the magnetic fields emerge vertically from the North and South magnetic poles and then round the equator they're parallel to the ground and so the the the the the bird in flying is able to sense the orientation inclination of the magnetic field uh there's a famous Ornithology ornithologist couple in Germany uh the vchos who would capture these Robins in mid- migration H and uh put put them inside these little sort of containers sort of U uh um cone shaped that have blotting paper ink uh uh ink at the bottom and blotting paper up The Sid so when the bird is at the bottom it gets ink on its feet and as it tries to fly to escape from from these containers it tends to want to fly out in the direction that to continue its migratory Journey So This Is How They established that it was actually wanting to fly in that direction how do they know it's a magnetic effect well they would put they put Helm Holts coils giant sort of magnetic coils on either side of the the Trap containing these birds and then could have these coils um in in the reverse polarity to the Earth's magnetic field uh with the same field strength so when you turn them on they cancel out any magnetic field and when they do that these birds fly randomly in all directions soon as they turn off the magnetic fields the the birds asense again the Earth's magnetic field and they want to fly in a particular direction so there was a famous paper in the 1970s in the journal science that established that these birds and then and later other marine mammals and insects have a built-in Compass some chemical Compass somewhere in the body that gives them directional information of course the mystery was where is this Compass how does it work now here we are 2023 and the only theory in town the only theory that H that has survived that is still in play is the idea that Quantum and Tang lement is playing a crucial role so quantum entanglement the idea that um two separated particles uh are part of a single system however far apart they are you have to describe them as a single Quantum state which means that affecting affecting one of them will will influence the other um it was also established that this chemical Compass however it worked resided in the bird's retina because it was light activated uh and so you know there's a there's a there's a a researcher in Germany in M who designs these experiments where he he he covers these birds with you know bit like the executioners mask that sort of covers the eyes and and once these Birds can't see they also can't sense the Earth's magnetic field so it's triggered by photons entering the bird's eye none of that is controversial that is all sort of pretty well established science of course what's controversial is how does it work the theory is in Quantum biology that photons enter the eye uh a photon will knock one of a pair of coupled electrons in an atom within a a protein molecule called cryptochrome that sits in the back of the retina the photon knocks one of these electrons off so it gets knocked off and it sits on a on an adjacent atom still within this large protein made of you know thousands and thousands of atoms but these two electrons remain Quant L which means that the way they spin whether they're both spinning up or one spinning up one spinning down the way they spin is very sensitive that the the um the way they dance together is very sensitive to their orientation in the Earth's magnetic field so even though it's very very weak it it's has the ability you know to to influence this delicate entangled state of these two electrons uh and then then when they collapse when entanglement disappears that sends certain messages to the bird's brain telling it the orientation in in the field what's fun about this is that quantum entanglement famously was a phenomenon a mechanism in quantum mechanics that Albert Einstein hated right he called it spooky action at a distance we are beginning to appreciate that quantum entanglement and is part of my my research at the moment is a fundamental feature of reality fundamental that we I feel we should be teaching undergraduate physics students about quantum entanglement it's not really something they encounter in standard undergraduate textbooks yet but the fact that quantum entanglement Einstein's spooky action helps the European Robin navigate its way down to warmer climates every fall has a c Certain Romance to it um so I I I would like this to be the correct theory of course liking something wanting it to be the correct Theory doesn't mean it's the correct Theory but but it it it it it's a fun interesting application of one of the the the weirder features of the quantum World quantum entanglement playing an important role in a in a living living animal helping it find its way just a completely tangential comment we can imagine what sight or smell are like for Birds but I I wonder what it must be like uh to sense magnetic fields and there sorry there's a paper that suggests that that that what the bird sees is like some sort of dark patch imposed augmented reality on its field of vision and and it tries to centralize that like a pilot trying to get you know the crosshairs in there when when they when they're flying in a plane I guess since you described this Pro this theory is or this process visually I mean it's taking place in the retina it would make sense that maybe they would experience it phenomenologically visual phenomenon but would this also just came came to my mind but would you anticipate that and maybe this experiment has been done that if you moved these birds to the southern hemisphere they would just instinctively start migrating in the exact opposite direction or is it sensitive to the polarity in it no I I think that's right I mean I'm not sure if anyone's done the experiment or but there may be other animals that have this Magneto reception this this sensing the Earth magnetic field but that would certainly be the be the implication you know wherever they are if they're near the North Pole or the South Pole their directional information would be towards the equator towards the direction where the magnetic field is more parallel to the ground so it they don't care which which hemisphere they're in it should be the same thing moving towards the equator and you you also said that I think this is just the only Theory that's in town at this point and it it seems like it's very well formulated but I might have take it that it it hasn't been experimentally confirmed and then would that be because of the reasons we sort of discussed earlier it's very difficult to do these experiments in Vivo yeah absolutely I mean all all you can do is is is experiment in vitro on individual protein molecules the cryptochrome molecules yeah and so you'd have to you know hit them you know with a a laser pulse or something like that and and and see if you can get some sensitivity to magnetic fields uh for the molecule sitting by itself whether that's enough of a Smoking Gun you know if that result confirms that there is a sensitivity uh I it may convince some but others may be harder to be persuaded well just to round things out you also mentioned Quantum tunneling earlier and Quantum tunneling in close to 200 episodes has never come up on the show and there have been a lot of episodes on on quantum mechanics so just what is Quantum tunneling and then where does it fit into certain enzymatic reactions yes so Quantum tunneling is is is a a feature of the quantum world that we've known since almost the beginning of the birth of quantum mechanics it was uh it's it's the way we explain radioactive decay um a particle say radium or something that's a nucleus that is radioactive that spits out an alpha particle that alpha particle shouldn't be able to escape the nucleus what it has to do is punch through an energy barrier uh what's called the kolon barrier um we now know that Quantum tunneling you know is is is everywhere it's the reason why the sun shines because uh two hydrogen atoms or two nuclei of hydrogen atoms two protons can't get shouldn't in in just describe in classical mechanics without any quantum should not be able to get close enough together to stick in the in the first step towards nuclear thermonuclear Fusion which is what gives the sun it it's light and and heat um because two protons are positively charged electrically so they repel so there's a barrier that stops them from getting too close but because in the quantum World these things aren't really discrete particles they they are spread out waves they can leak through these energy barriers I always talk about it like a it's like a ghost or Phantom passing through a solid wall there's a certain probability that these two protons can or think of one staying where it is and the other getting through the energy barrier once they get close enough then the strong nuclear force which is an attractive Force at very close distances kicks in and they bind and then you get the you know the process of hydrogen the first step of hydrogen becoming helium uh in in in infusion um but it's it's it's a it's a strange effect it's it's a bit like kicking a a soccer ball up a hill you got to give it big enough kick to get it over the the the the hump of the hill in the quantum world you could kick it halfway up and it still has a non-zero chance of disappearing on one side and just reappearing on the other it has Quantum tunneled through a region where were it a classical particle it would not be allowed to to to pass through so we see this all the time in physics and chemistry it's not a surprise what was a surprise was to find it taking place inside living cells uh the first people to to to see Quantum tunneling was quantum tunneling of electrons uh uh uh in in spectroscopy in the 1960s then in the 1980s a group at Berkeley and California saw Quantum tunneling of protons 2,000 times the mass of an electron so clearly much more difficult you know a heavier particle but nevertheless Quantum tunneling from one part of a a molecule to another and they showed that enzymes make use of this trick in moving particles around enzymes essentially are the workhorses of the cell they they break and build other particles proteins inside the cell and one of their tricks is to to Shuffle and move particles around and they use quantum tunneling to do this part of the time so that was established in the 1980s so it's not like you know a very recent thing uh what we're interested in is is quantum tunneling in a different uh mechanism namely in the hydrogen bonds that hold the strands of DNA together that that's that's what the new area is that we're looking at H and so then in in both of these cases with with the Robin and the DNA the idea is that entanglement and tunneling are are fundamental features of the world happening all over the place and then as you said earlier it's only natural that through natural selection Evolution would take advantage of these features for Reproductive success yeah but it by taking advantage of it e it life would have had to evolve the ability for this Behavior to take place in cells in a way that it wouldn't normally take place in inanimate matter with that temperature with that complexity I mean the DNA example is that you've got these um the double helix the strands of DNA is like a twisted ladder the rungs of the lder are hydrogen bonds those are as far as I'm concerned those are protons I you know I don't I don't talk about hydrogen atoms because my background is nuclear physics so I don't care about the electrons I leave them for the clists I you know I deal with the the nucleus of hydrogen the proton so this proton can Quantum tunnel across from one side to the other um we've we've published several papers over the last few years uh very sophisticated sort of computational chemistry simulations to show that this is very likely to happen um and if the proton Quantum tunnels from one strand of DNA to the other then when the DNA strands unzip in the process of replication you know you unzip them and then each one has a a copy made of the other one that it attaches to and you get two double heles um if the proton's in the wrong place in any one of these sites between the two strands that could lead to a mutation in that base uh and so it's important you know that life has has life evolved the ability to see these Quantum effects the point is that Quantum tunneling quantum entanglement Long Live Quantum coherence as another example in in photosynthesis where Quantum biology uh biologists are interested should all disappear very very quickly decoherence should kill off any quantumness far more quickly than the processes of life can make use of uh and what seems to be happening this this is what what really interests me is is the structure of the environment surrounding this Quantum system such that it can Stave off decoherent uh maintain Quantum coherence for long enough for it to play a biological functional role so you know the structured environment is is what's interesting and if that is true when you know then hey why not life has had billions of years you know so it will any tricks that might have been available to it it would have finessed over generation after generation after generation and so those cells where that they've been able to maintain Quantum effects to give life an advantage will have been the ones that were selected for so but it must be something special about life and evolution that allowed it to choose uh the these processes where quantum mechanics can play a role so decoherence has come up a couple of times mainly in the context of the everettian theory of of quantum mechanics and this being the mechanism of the branching of the many worlds but I don't think that we've ever gone into much depth into what it really is and I I had been holding off on it because I knew it would come up when we talked about the arrow of time but maybe now is a good idea to just lay out theoretically what Quantum decoherence is since we've talked about it so much yes um I it's a bit like entanglement it's one of it's one of those uh uh features of the quantum world that is not t thought at a basic level and I think it's so vitally important that it needs to be when we teach quantum mechanics to undergraduates in physics or chemistry classes um we tend to deal with very simple isolated systems and we solve the shring equation of quantum mechanics and so you know a particle at some time uh is behaving in this way or Quantum state is behaving in this way and you evolve it in time by solving the shrouding equation and you see what is h what is doing at a later time and then the standard way we teach quantum mechanics to say and then we measure it and the the probability of finding a particle say in a certain place or with a certain energy or with a certain spin is is the numbers the math gives us that that probability but there's nowhere in that the way we teach quantum mechanics how that measurement takes place what is happening when you look when you open roding his box with the cat inside dead and alive at the same time what is actually happening so the everettian view uh is one that says you know right we've we've solved the problem that what is happening is that the quantum State never collapses but you know there are all these different options and when you make a measurement you are just in the universe where that option is realized and there's another you so but decoherence theory is is more General than that decoherence is the the means by which the Sur the environment surrounding a Quantum system interacts with it uh in a sense you can say measures it but interferes with it or gains information about the system and it's inevitable that decoherence will take place because the fact is there is no isolated Quantum system in in the universe apart from the whole universe itself so one could imagine some God's eye view outside the universe and say well the universe never decohered you know because there's there's no environment outside it for its information to leak out into but within the universe any system we want to know something about inevitably cannot be maintained indefinitely isolated from its environment decoherence simply means the leaking out of quantum coherence something that can be in two places at once I have more than one energy at the same time we'll be spinning up and down at the same time you know all the stuff that happens in the quantum World um that information leaks out very quickly in the into the environment so the environment causes this quantumness to to DEC ah here in the same way as a you know a hot cup of coffee in in the fridge will leak out its heat so it's a bit like thermodynamics in the sense that in in thermodynamics heat leaks out from from a hot system to a cold in the quantum world we talk about Quantum coherence leaking out into into to its environment um we may come to this in a moment but another way of saying this is that it becomes entangled with its surroundings and Tangled with its environment so decoherence is a is a is a universal process it happens all the time you prepare a Quantum state that is starts off isolated from its environment and inevitably it becomes entangled and and and uh decoheres its information into the environment in a oneway oneway process do we need everettian quantum mechanics well the measurement problem uh I don't want to I won't get technical but I justv say the measurement problem is actually comes in three parts uh the first two parts called the the the preferred basis and and and then the uh the collapse of the off diagonal elements of What's called the density Matrix technical mathematical terms they're solved by decoherence you're still left with a final stage of the measurement problem which is why physicists still worry about the measurement problem that you can only explain if you plant your flag on a particular interpretation of quantum mechanics you either say there are many worlds this is everettian view or you say there are hidden variables or you say the quantum State undergo some sort of physical collapse spontaneous collapse or you say I don't care that's the Copenhagen view you say I don't I just want to calculate I just want to work out the numbers and follow the recipe so decoherence is as a physical process it's not controversial anymore it's been around for 50 years it's been Quantified and and and and formulated developed mathematically but it doesn't solve all the mysteries of quantum mechanics there is still then your still a requirement to to choose an interpretation to explain to us how we observe the quantum world how we see it how we bring it into reality this is orthogonal to the direction in which we've been going but since you mentioned hidden variables in Copenhagen I'm wondering if there is a specific interpretation that uh you put your uh chips on I for many years since I was a grad student I was never happy with the Copenhagen view so that's the stand it's called Copenhagen interpretation because um the founding fathers of quantum mechanics worked at Neils B's Institute in Copenhagen so Heisenberg and poy and and enrio fery and others all spent time there um and it's not really an interpretation it's a it's a recipe right it says quantum mechanics works the math all developed and and and uh detailed and it helps us learn about the quantum world without the the the mathematics of quantum mechanics we wouldn't have understood the structure of atoms and molecules we wouldn't have nuclear and particle physics we wouldn't have developed modern Electronics we wouldn't have developed computers I wouldn't be talking to you um ac across you know the internet and so on so the Copenhagen view is very often some people talk about it as the shut up and calculate interpretation the other the interpretations that I prefer are what are called realist interpretations what they say is that there has to be a theory that tells us how the quantum world does what it does it's no good saying it does it I don't care all I'm interested in is the results of measurements the results of experiments I want to know how the atom gets from a Tob it must do it somehow if I can't decide that's my problem nature doesn't care whether I'm you know I'm shutting up and calculating or whether I'm racking my brains trying to figure out how it does it in some way so there are multiple ways of in fact I think I tweeted about this today there was uh there's a there's a Twitter account I follow called physics in history or something like that and had a very nice summary of about a dozen or so different interpretations it started with Copenhagen then it went on to everettian many worlds ban hidden variables I'm agnostic about which of the realist interpretations uh uh works and the three Front Runners will be everetti in many worlds Boman or de Bry bone pilot wave theory or hidden variables and spontaneous collapse theories in order of choice were I allowed to to to choose which one I want to be the correct one my preference is Boman mechanics hidden variables okay interesting so yeah so I mean everettian quantum mechanics I'm I'm I can see the the attraction I'm I'm persuaded by the attraction but I have that metaphysical mental block about infinite universes that still bugs me yeah I've done a couple of episodes on many worlds I Tim mlin whose a friend is is very big on on Boman mechanics I've done a couple of those but I haven't done any on spontaneous collapse or Gerard Rini Weber but that's right that's uh that's coming up in the pipeline but okay I've mentioned times Arrow uh a number of times already so let's let's get there uh and so macroscopically I mean we see time as flowing in One Direction namely from from past to future but do you find it useful at all to distinguish between different arrows of time when you talk about this there are certainly lots of different erors at time that at face value don't seem to be connected with each other you know there's there's the arrow of time pointing in the direction of the expansion of the universe there's the aror of time that's pointing in the direction of increasing thermodynamic entropy increasing disorder uh you know or or the boltzman error of time in statistical mechanics it says it's just um statistically inevitable that you know when you you you shuffle a pack of cards they're going to become more disordered not more ordered but yeah there are other Arrow of time there's you know there's the arrow of time that that tells you that um effect follow follows cause or that um uh waves spherical waves are outgoing rather than incoming and and and and so on whether these are all connected or not I I mean at some fundamental one have would have to assume that they are but the other option is that there is an arrow of time baked into the universe and these processes are following you know the arrow of time comes first it's not that the processes come first giving you an arrow and then you worry about how to unify the arrows there's a single Arrow of time and these processes all point in the direction of this arrow and that's that's the sort of idea that I'm I'm thinking about um I'm I'm currently writing a paper with philosopher of physics Eddie Chen in San Diego yeah yeah yeah you know Eddie I haven't talked to him yet but I know that he's part he's been recommended to be on the podcast a number of times he's yeah he's part of the John Bell Institute which is right how I I found yes well he's he's a collaborator with me on our research uh program funded by John Templeton Foundation uh so so we uh we talk a lot I was when I was in uh in the US last week before I was in the Bay Area I was down in La we had a two- day workshop at UCLA uh organized as part of our research program and and I had a nice long chat with Eddie there developing some of ideas along these lines the AR of time I was just I think I was hanging out well I was hanging out with who I think is his graduate advisor at at ruers um very lower this weekend so right okay yeah that's funny the the only other arrow that I was thinking of is the psychological arrow that we we remembered the past and yeah and not the future but the significant point is that these are all macroscopic arrows pointing in One Direction and presumably have some underlying connection yes yeah what does it mean then to say that at the quantum level so at the macroscopic level time appears asymmetric for this reason that's another way of putting it what does it mean to say that at Quant on Quantum scales time is symmetric do you have like the evolution of the Schrodinger equation in mind uh yeah so well in fact I mean it's symmetric In classical mechanics in just Newtonian equations of motion similarly they're called time reversal and variant you switch time to minus time you know you run the movie backwards down at the microscopic scale albeit described by classical mechanics and again there's no difference time you know can run forwards or backwards down at the quantum scale you switch time time reversal invariance in the quantum world is a little bit more technical because you don't just switch T to minus t you have to take the What's called the complex conjugate of the wave function and so on um but yeah the fundamental equations of Dynamics and indeed in relativity Theory are time reversal invariant which means they're symmetric in time and so the usual argument is which goes all the way back to the 19th century something called lmi's Paradox which says if our fundamental laws of physics are symmetric in time how do we see an arrow of Time how does the arrow this Arrow of time that you know is so manifest even whether it's you know our memories of the past but predicting the future entropy increasing and so on and so forth how does that emerge from symmetric fundamental laws my view there are there are others who who who who who have thought and written this way Roger Penrose is one Lee smolen is another my view is that the arrow of time is more fundamental than these time symmetric equations the AR of time is baked in to reality the equations that are time reversal and variant time symmetric are approximations because they only describe isolated systems so this is what leads to entanglement and decoherence ideas there is no such thing as a truly isolated system yes if you put a pendulum in a box and in a vacuum and set it swinging you know in principle it'll swing forever if there's no damping um but nothing is completely isolated from from its surroundings at some point there'll be interaction even the cosmic microwave background you know will will have an effect at some point so nothing is isolated everything is is is an open system and therefore there is no such thing as absolutely 100% time reversal invariance anywhere in our universe other than the univer entire universe itself I'm not interested in the entire universe itself I'm interested in being able to say something about some part of the Universe I can't step outside of the universe to talk about it so for me that's not interesting I'm not a cosmologist anyway but the fact that everything is open means there is always down at the quantum level entanglement decoherent and that immediately gives us an arrow of time an arrow pointing in the direction of increasing entanglement in um increasing decoherence so the shring equation which is time reversal invariant is only an approximation because it only describes isolated systems which don't exist in the real world does that sound convincing it it sounds convincing until I start thinking about the the different interpretation so the like many worlds the the Schrodinger equation is all there is really to describe everything and there is only one well it's all there is for the entire universe it's it's not all there is when you describe a system um you know the in in everettian quantum mechanics you know you you open Schrodinger's Box uh and uh you make a measurement you see the alive cat or the dead cat before you open the box it was it was both it was alive and dead of course before it's decohered before decoherence has taken place it's could be alive Dead Alive dead at the same time decoherence kills off the alive dead at the same time but you still have the two observable um States the alive and the dead it's not that before you open the box is just your ignorance both States exist as far as you're concerned they're both opening the box you see an Al live cat there's another you in a parallel universe Hees a dead cat but that measurement process has given you the hour of time um the shring equation worked before because it was assuming that the the box is isolated from the surroundings at some point a measurement has to take place which is another way of saying all systems are really open systems and how though connecting back to biology how how does this all connect to the era of time well in a in a paper that we are hoping I mean it's it's it's been to the Publishers reviewers have got back we've made some changes we've you know as in the process we've submitted back I'm hoping it'll it'll get published sometime soon this is another paper on the um proton tunneling in DNA uh and a surprising result we found is that in the process of unzipping the two strands of DNA there's a particular molecule an amino acid that seems to do the measuring it's like opening the box Shing is cat's box um until then the surrounding environment the water essentially surrounding the DNA causes decoherence but only partial decoherence so it's not fully decohered it's not it's Quantum What's called the vman entropy is at maximum so it's there is still quantumness going on there and the proton can still Quantum tunnel from one side to the other but once it starts unzipping that proton has to make up its mind right you you can't be in both States at once once the two strands are really separated the barrier between them is too big uh and this inside this um enzyme called the helicase which does the unzipping it also plays the role of measuring so it's if in an everettian view for example it is building in the hour of time by making making a measurement saying that you know the proton on this side and then atium would say in another universe that enzyme found the proton on the other strand of DNA so both exist in different universes so so this Quantum measurement uh is taking place inside living cells all the time uh and my argument is that the arrow of time is already there it's already baked in uh an entanglement increasing entanglement is the direction in which the arrow is pointing I see so it it's kind of like this other arrow that we didn't mention the the direction of wave function collapse exactly the direction of measurement so this process sort of imposes the direction of time on the quantum phomen and every interpretation will will talk about this Quantum AR of time different the Copenhagen view will just say uh an OBS a measurement is made right and and and your what what was called unitary Dynamics you know time reversal invar Shing equation you can't use that anymore because you've made a choice um and everum will say it's the branching of the many worlds that gives a direction in time the uh the uh spontaneous collapse grw approach says that you know every now and again the the the wave function of the system collapses uh to a particular state that you can't go back you can't uncollapse right so so that gives it so the all different interpretation ations have to have in them built in somewhere this directionality to the era of time well one other dimension of the work being done at Sur right now involves or that I want to ask about involves something called Green florescent protein and I'm wondering how it's useful with regard to well one what it first I'm wondering what it is and then how it's useful with regard to coherence and Quantum biology and what we've just been discussing these fluorescent proteins are a good example of trying to study long- lived Quantum coherence you know a system that can be in multiple energy states at the same time um the motivation for it is because it's a good um model of a more complex system namely the process of photosynthesis we know that plants and bacteria photosynthesize they capture sunlight they deliver it to the to reaction Center in the cell and one of the earliest um uh suggestions in Quantum biology is that photosynthesis requires a Quantum explanation namely that Photon that lump of of energy follows multiple Roots simultaneously a bit like the particle going through the famous two slit experiment in quantum mechanics it's an interference process that allows that Photon to reach its destination with such high efficiency without quantum mechanics it would just be like a pinball randomly bouncing around inside the cell and more than likely be lost as waste heat but it doesn't it coherently reaches its destination and so Quantum coherence in photosynthesis is another thing that is being studied and the g green fluorescent proteins which you can take put them inside in a in a laboratory in your experiment zap them with these rapid laser pulses and see how they excite and de excite is a means of studying whether Quantum CER can last in biological systems for for long enough to to have a functional role well I'd like to finish with just one last question a more speculative question but so if you think that understanding the connection between time Symmetry and quantum mechanics and biology might point the way to some sort of insight that could better help us understand what distinguishes life from the inanimate I'm wondering if if you think this could have huge implications for how we distinguish or might distinguish upon arriving at or otherwise exploring strange new worlds alien chemistry from alien life for instance possibly I mean it's it's sort of you know we you can go to to sort of workshops uh or or or talk to you know other physicists chemists biologists where some of these ideas are you know talked about uh you know what is it that that that indicates life what is the difference between biology and chemistry um does quantum mechanics play a role and so yeah there is a there is a a mix between the two so the people for example Arizona you know Paul Davis is beyond Center you know they they're keen on origin of Life foundations of quantum mechanics Quantum biology and inevitably these areas all get sort of mixed up and shuffled together but it's sort of still a bit fluffy you know and you can talk to hard-nosed you know chemists and physicists um who will say no look you know you're you're trying to find this is you know it's like bordering on vitalism you're trying to find some magical you know quantum mechanics has replaced you know the magic pixie dust that sprinkles on inanimate mat and end Dows it with life so one has to be careful uh and I think certainly with Quantum biology taking small steps even though it's cool to say Quant mechanics explains the origin of life or quantum mechanics explains Consciousness or whatever I think there's a danger that it it can spill over into more speculative areas than we're prepared to be able to stand up and justify just yet maybe in years to come well Jim this has been super fun and a lot of Terra incognita for me in the show so thanks so much for taking the time to have this conversation with me my pleasure been good fun a