The Life Scientific: Peter Knight

0:00This BBC podcast is supported by ads outside the UK.

0:30Peter Knight:at Whole Foods Market. Apple Vacations, where your story starts. The July Savings Event from Apple Vacations is here. Book by July 23rd and save up to$400 off your flight and hotel package to Mexico, the Caribbean, Central America, Hawaii, or Europe. From all-inclusive escapes to bucket list adventures, Apple Vacations makes it easy to create memories with the people who matter most. Start today at applevacations.com or contact your trusted travel advisor.

1:03Hello. There are some computing tasks and mathematical problems so hard and complicated that it would take today's most powerful supercomputers literally millions of years to crack them. But in the next decade or so, we're on course to creating a new kind of computer that could solve such problems extremely quickly. Welcome to the new world of quantum computers, whose tremendous power comes from exploiting the laws of nature that govern the weird behaviour of atoms and subatomic particles, the laws of quantum mechanics. Sir Peter Knight, Emeritus Professor at Imperial College London, is one of the UK's leading quantum physicists, a pioneer of the fields of quantum optics and quantum information.

1:46For more than five decades, Peter's research, along with his many leadership roles in UK science, have helped to take these remarkable fields from the realms of the esoteric to the frontiers of a new technological age. He's been the driving force behind the UK's National Quantum Technologies Programme, a£1 billion government-funded endeavour to put Britain at the forefront of the commercialisation of quantum computing, along with a host of other incredible and revolutionary inventions. I'm very pleased to say he's my guest today. Peter Knight, welcome to The Life Scientific. Well, thank you so much for inviting me here.

2:20Peter, many listeners won't know this probably, but the United Nations has designated 2025 as the International Year of Quantum Science and Technology. And you're one of its lead organisers. So what's its purpose and why 2025? Well, it's 100 years since the discovery of the fundamental laws of how the universe behaves at the microscopic quantum level. So we're celebrating 100 years of achievement, things that are quantum-enabled, lasers, semiconductors, all the things we take for granted in our technology world, but also the new things that are emerging in quantum now. So it's the right time, really, to celebrate how this has transformed the world, how it's affected people in their everyday lives, and how ordinary people will play a role in this as well.

3:08And some of those inventions that you mentioned that built on 100 years of understanding the quantum world, you know, as you say, semiconductors, computers, and pretty much the whole of modern electronics, really, we often refer to them as quantum 1.0. Of course, that's because, you know, we've got something else coming up the road, quantum 2.0. But quantum mechanics, as I think a lot of people know, is notoriously hard to understand. So what is it about the quantum realm that makes it so strange and yet so remarkable? Quantum leads to ideas that are very counterintuitive. So, for example, in quantum mechanics, you can put things into a thing called a superposition.

3:51Quantum things can be here and there at the same time. And the here and there at the same time is not something you ever experience in the ordinary world, but it's something we can exploit. In fact, we exploit it every day. That's how atomic clocks work. and atomic clocks power GPS and the way we navigate, we do our timing and so on. So already this counterintuitive here and there at the same time, superposition, gives us something which is of great economic benefit. Of course, there's lots still to uncover and to understand. You know, there are deep mysteries that we still need to understand, so the journey towards understanding is still continuing.

4:28But we've already uncovered a great deal that we know that we can use in the everyday world, in imaging, in communication, and as you mentioned, in computing. And yet the whole idea of the weirdness of quantum mechanics has made it into popular culture. A lot of listeners probably will have heard of Schrodinger's famous cat in the box that's both dead and alive at the same time, exemplifying just how counterintuitive these ideas are. Exactly. And what a quantum computer will be doing is putting quite large arrays of atoms or semiconductor material into a kind of giant Schrodinger cat, by the way.

5:04And so all those philosophical questions that we used to amuse ourselves with as students have become part of technology. We're going to come unpack some of these ideas later on. But Peter Knight, let's talk about you and about your early life. You were born in 1947, two years after the end of the Second World War. Tell me a little bit about your parents and your home life as a child. Right. Well, working class background, semi-rural. It's not rural anymore. The town has eaten up the area that I was born in. But it was pretty much rural then, two up, two down, outside lavatory. Nobody in my family at that point had ever been to university.

5:44My parents were really, really supportive in trying to make the most of opportunity space. and in particular very keen that I had all the opportunities through what was then called the 11 plus and I ended up with a scholarship to what's now a minor independent public school and that really gave me a tremendous opportunity to have fantastic teaching. And once you got into this school, was that where your interest in science flourished? It did and we had really great teachers. Curiously, my interest was actually in chemistry. And, you know, we had a barn and I built a laboratory in the barn. And like all young teenagers, you know, I was really interested in things that either smelt disgustingly or exploded.

6:31Or made a loud noise. Yeah. And but chemistry was. And in fact, I went to university initially to do chemistry. Right. But with a physics minor. but it was chemistry at school that really got me really fascinated by the role of science and what you could do in that world. Well, in 1965, as you say, you started at the University of Sussex to do a degree in chemistry but then you switched to major in physics. What was it about the University of Sussex that attracted you apart from being by the sea in Brighton? It was a new experiment at that point. It was one of the very first of the new universities it was led by some really charismatic people who were trying to break down the barriers between disciplines, redrawing the map of learning.

7:18The idea that these artificial barriers, the silos between disciplines could be broken down so the ability to do a degree course where you could pull in things from different areas was really attractive to me. Plus the fact that they've attracted unbelievably charismatic, at that point, young people. It didn't seem young at the time to me, but they really were. who were inspirational. Some of whom went on to win Nobel Prizes. I was taught spectroscopy by Harry Croteau, who got a Nobel Prize. Oh, this is for Buckyballs, carbon C60. I was taught solid state physics by Tony Leggett, who got a Nobel Prize for superfluidity.

7:56So, you know, it was a transformative experience. I understand it wasn't just science, though, that occupied you as a student, because you also were really good at getting some big rock bands to the university to play. The 1960s was a wonderful time to be part of student life. And student life in those days meant bands, bands that later became unbelievably famous, but at the time made a living from the university circuit. I think we gave Pink Floyd their first gig outside London, for example. It was a fascinating world. I've still got contracts from some of the people that we brought into university.

8:3650 quid contracts for Eric Clapton, for example. But it was a distraction, really. And, of course, it didn't take very long, and I was back into my PhD. Right. And you stayed on at Sussex, actually, to do your PhD. This is 1968. And not long into your PhD, you came to realise that you were much more suited to theoretical physics and working with equations than doing experimental work in the lab. What happened? Well, all undergraduates at Sussex, and I think it's pretty much uniform around the country now, do a final year project, which is basically in a research group. And I worked on what was basically a quantum optics experiment.

9:16But it was a very simple one that generated really quite interesting fundamental understanding. And I got deluded into thinking that that's what experimental physics could be. So I started a PhD with the idea of doing quite a complicated experimental project, which also required theoretical understanding at the same time. And it didn't take me very long to realise I was totally incompetent at very high level experiments. And to my colleagues' huge relief, I said, I think I ought to be a theorist, not in the lab. And they all cheered at that point. Yeah, that's probably the sign. But of course, in science, I think in physics in particular, I'm certainly strongly of the view that theorists shouldn't work in isolation from the real world.

10:03They need experimentalists to check their theories and predictions, but vice versa, of course, as well. Experimental results need the theories to interpret and explain them. I strongly agree with you, Jim, on this one. And I think one of the unfortunate features of British science in the past was that there were silos of theoreticians who worked often in mathematics departments and experimentalists and are quite divorced. And a very much a feature of my career is to be embedded in a group that could do theory and experiment and talk to each other where theory could influence the experiments. New experimental insights could tell us what next we could we could try to predict.

10:42And that symbiosis of theory and experiment, I think, is a characteristic of what we tried to change in the way that we approach this in the UK. Back to the late 60s and early 70s, Peter, you were working in this nascent field called quantum optics. Can you explain very briefly what this is? Yeah, it's a funny fusion of two areas. Quantum, looking at the way that the atoms are structured and behaved, and optics, the science of light. And of course, the fusion together means that, you know, how does light behave at that fundamental level? How does it change atoms and so on? And it was a very early field, basically.

11:19And one of the things that I think I really benefited from was being in at the start of an emergent field where there were many, many things to uncover and discover and explore that hadn't been worked over by many others. So the beginnings of quantum optics already begun to demonstrate that there's a new landscape out there that we could explore of enormous importance. And I guess helped by the then sort of newly invented laser. The laser was the transformative part of it all, of course. It meant that suddenly we had a source of light that's pure, intense, it can change atoms, and equally atoms can change the laser light as well.

12:00So all of these were part of what we were trying to understand, But it was initially a very small field. I went to the United States as a postdoc. And when I came back, the community was maybe six, maybe seven individuals. In the whole of the UK. All universities. And so it was the Wild West. There were so many things to do. And because the opportunity was clearly identified by very bright young people, I had some fantastically good students who then joined me. And they became the engine of the subject later. And of course, today, you know, almost every university physics department in the country has quantum optics theorists and experimentalists.

12:40Awful lot of them were my students as well. Do you know what? I was going to ask you this later on, but I'll ask you this now because I will bump into top physicists who will say Peter Knight was my PhD supervisor or he was my first boss in my research position. What does it feel like to be a mentor to so many of these leading physicists that we have today? It's a feature of my career that I'm most proud of. You know, if I had to work out what have I done in the several decades of this, a researcher, a teacher and then later on a policy advisor, it's the teacher side of it that I think is the most valuable because the cadre of people, the quality of what they're able to do, their imagination.

13:21I've learned so much from them. Well, let's dig in a little bit to the science, to quantum physics. I know this is what listeners are wanting to hear about. But your research, Peter, has covered many aspects of the quantum nature and behaviour, of course, of atoms and of light, or more specifically photons, the quantum particles of light and how they interact. One of your main thrusts has been to understand this strange phenomenon called entanglement. But before we get into that, we need to know a little bit about a related concept, superposition. You mentioned that earlier about something being in two places or two states at the same time.

13:57Let's see if we can unpack it a little without scaring off too many listeners. So superposition first. Right. So what you've got in quantum mechanics is the ability to understand the way that the energies of that system can be partitioned up in a discrete way. Okay. The energy levels of an atom. A lumpy energy rather than continuous. Exactly. Right, exactly. And that discreteness, the transition between one discrete level and the next, is where you get light from. That quantum jump from one state to another generates a photon. Because it's like an atom that has a certain amount of energy. It can spit out a precise amount of energy and drop down to the next level.

14:40Exactly. And it could be doing it spontaneously, or you could trigger it by another photon. That's called stimulated emission, and that's how a laser works. OK, so you can be this state and it'll jump to that state. But what you can also do if you're really smart is to say, I'm going to put it in this state and that state at the same time by manipulation. Of course, it won't last very long. It interacts with the world and it's fragile and it falls to bits. And it's only in this state or that state rather than this state and that state. The cat is either dead or alive, not both at the same time.

15:11It's either dead or alive. And that superposition is the really counterintuitive thing. And so if it hasn't, it's so fragile, if it hasn't just dissipated away because of its surroundings, when you look at it, you force it to make up its mind. Exactly. So the observation gives you a precision. It's really there with some knowledge. So we've just explained quantum superposition. So what is quantum entanglement? Quantum entanglement actually comes from superposition when applied to more than one atom or more than one quantum of light photons, for example. When you've got more than one of them, they can be, in a quantum sense, entangled, which means that they're correlated.

15:52And by correlation, it means that if you measure one, you can infer immediately the properties of the other. However far apart they are. However far apart they are. Now, that's not to say that you get instantaneous communication. There are no faster-than-light communication here. but the ability to infer what's going on in one system because you've measured the other system because they're coupled together in this entanglement sense is the heart of what we're able to exploit so can you give me an example then of a technology or a device that's been developed which exploits this phenomenon of entanglement right so light beams can be entangled different colors of light beams can become entangled okay and it's something i've put a lot of work in on over the years on the theory of it remarkably a group of experimentalists have started to work out ways in which you could exploit that if the light beam is entangled different colors are highly correlated so ability to do something with one you can infer from the other the properties of the other what's going on now the wonderful application of this is an imaging system called an entanglement camera this was all done by by colleagues within our uk program in glasgow and imperial college working together the entanglement camera can correlate red light and blue light red light is great for medical imaging cameras are terrible in the red blue light terrible for medical imaging cheap cameras in your phone so what you do is make your correlated red and blue they're highly correlated the red goes through your sample the blue goes to the camera because they're correlated you get an image in the camera from blue light that never saw the object but has an image of it it's called ghost imaging that entanglement camera is being used already to improve the ability of an oncologist to have more confidence in breast cancer imaging isn't that a great that's an amazing story it's amazing that you you're using light to image some part of the human body but you can't use that light in your camera so you entangle it with a different color light that is better used in the camera right and because they're entangled because they're correlated connected with each other it's one of my most favorite examples great potential well this entanglement camera is one of the earliest commercial devices made possible by the uk national quantum technologies program now you were the driving force to get this program established back in 2013 and as of last year funded by the UK government to the tune of more than a billion pounds.

18:35Can you outline what the program does and how it works? You've seen already from some of the things I've been talking about that we had a really strong research base in quantum physics. Equally we got quite a strong industrial presence in the area called photonics, basically the industry that uses light. bringing those two together in a journey was part of the purpose of what we're trying to do so how do we get researchers in the UK to work out how their collective strengths can do so by building the collaborative enterprise a bit more working out what the vehicles are for encouraging commercialization working with government laboratories and so on so the first thing we did is to have enough resource that funded people on that translational journey with within research hubs so initially we had four research hubs concentrating in in in the four key areas of quantum technology uh now we've got five and an extra one in terms of of health care that involved about 30 universities altogether so it was a collective enterprise and it's really interesting to see how with the right resource people are much more comfortable about working together in an enterprise than competing separately by the way i think that was part of the clue The next part of it was to work out how we actually then encouraged the commercialization of this.

19:56And that was through the adoption by existing companies, but also the fostering of new companies that emerged. So existing companies like British Telecom already heavily committed to the field. But equally, lots of people started to think about startups. How do you support startups? How do we get collaborative R &D projects going? And so one of the things that I was responsible for was, I think, called the Industrial Strategy Challenge Fund for quantum, which was pre-competitive stage, how we could generate higher technology readiness levels. In other words, the ability to actually produce a product out of the lab.

20:36So initially, I guess we spent about$150 million on the Industrial Strategy Challenge Fund side of things. companies invested on on those same projects more than three times that so what we were able to do is in other words to build a catalyst for that kind of investment so we've got about 40 quantum companies now some of them doing really well startup money from venture capital is second only to the us so i think we've got a flourishing ecosystem of moving things out the challenge that we have now is how to do stuff at scale where do we get the resource so these companies can grow and survive in the UK and that's part of what we're trying to do now initially I guess you had to persuade these companies that these are technologies that are ripe for commercialization rather than just simply some sort of concepts in the lab that are years away absolutely right so companies like british telecom have the ability already to say okay we can see in the lab it's working already and we can move on with this we can partner with toshiba research in cambridge that's fine companies like bae systems who are really really interested in the sensor program will want to see a prototype and so we've enabled our hubs to build some of the prototypes on this one so i think that's been part of the the seamless journey i know that this initiative began for you as a passion project after you retired from Imperial College in 2010.

22:09So where would you say the UK ranks in the broad area of quantum technology on the global stage? If you look at measures of industry engagement, we're probably second to the US in terms of venture capital, product that's beginning to emerge, customers and so on, probably second to the US. If we look at the scale of investment, we are third in the world probably because China has resource, which is probably, and we have to rough and ready estimates, China's investment is probably equal to the rest of the world's added together and led by incredibly distinguished people. So, you know, they are also doing wonderful work in this space.

22:56So they have an absolutely massive budget. The US, probably second, and then us. Well, let's start on quantum computing. As you say, one of the major goals of this national program. Now, if we try to explain in any depth how quantum computers work, we're going to be here all day. So in essence, what is it that they can do that today's most powerful computers can't? A quantum computer, when run in an error-corrected manner, without any faults, has the capability of doing things that classical machines are unable to do. In particular, they change what's sometimes called the complexity class. Things that are thought to be exponentially expensive become, perhaps polynomially, less demanding.

23:48We may have to unpack what exponentially and polynomially mean. So things that could take the age of a universe to calculate, even on the biggest supercomputer, could actually be performed probably in seconds. It's not easy because fixing those errors is really the challenge. But the journey has really accelerated, and I'm pretty confident now. So the UK quantum mission, quantum computing mission, says by 2035, we will have a quantum machine capable of doing a trillion operations before it falls over. That's pretty bold, but there's no harm in being ambitious. Is it realistic? I think with the progress we've made in the community over the past 18 months in fixing error correction, it's now become realistic.

24:41think. What uses will quantum computers be put to once we have them? How are they going to impact our daily lives? There are many things that we want to be able to change in our ability to understand things that affect us. The way that we design new drugs, the way that we build new chemical processes, the way we could actually improve on some of those processes. So a quantum computer for example will be able to understand and to model things that the natural world already do now an example of that is the disproportionate amount of energy we use at the moment to fix nitrogen for fertilizers plants do it very easily at room temperature whereas we have this horrible thing called the harbour process so if we could understand a lot more about the synthetic fixing of nitrogen, which is one of the goals of a quantum computer, for example, in quantum chemistry, that would transform our ability to think about the agricultural productivity of the world.

25:48A national grid are investing in the area because they want to understand how to deal with load balancing. When you've got lots of generators and demand is rising and falling, how do you optimise it? That's another application of quantum computers. Which classical computers find difficult to solve. Well, if you've got 10 generators, it's easy. You can do it manually. Turn that one up, turn that one down. If you go into a world of renewable resources, you will have thousands of generators. Then it becomes a mathematically complex problem that you can't handle. I guess I might know what your answer will be to this question Peter but looking back over your your long career what would you say has given you more satisfaction or the most satisfaction your your research work in quantum optics your your role in setting up and guiding the country's national quantum technology program your mentoring what is it that you look back on feel most proud of I think what I'm most proud of is mentoring the fact that we work with some of the brightest young people from around the world actually and allowed them to flourish to work out opportunities for them you know often as a broker to see how that could work for them i think that's what i'm most proud of because we built a cadre of people don't always agree with me which is exactly right but the ability to be able to learn from them and from them to learn from me and build a new subject that's what's most satisfying.

27:16Well Peter you retired from academia back in 2010, 15 years ago you've been working just as hard on your university pension long may it continue Peter Knight thank you very much for sharing a life scientific. It's been a pleasure, thank you for having me. How did a boycott Jimmy become a billionaire from posting videos? On Good Bad Billionaire we're going to find out how the world's most popular YouTuber Mr Beast made his fortune. He's buried himself in a coffin for days. Counted to 100 ,000 on camera. And even recreated Squid Games, all in an attempt to go viral on the internet. But it all started when he gave a homeless man$10 ,000.

27:56So is he a philanthropist reshaping capitalism? Or is he just the king of the attention economy? Find out on Good Bad Billionaire. Listen on BBC.com or wherever you get your podcasts.