Alain Aspect


Nobel Prize Conversations

“I am fundamentally a professor. I love teaching and explaining difficult things”

Ever wondered how to boil an egg to perfection? In this podcast conversation, physicist Alain Aspect shares his best advice on how to cook the perfect egg. Together with the Nobel Prize’s Adam Smith, he also speaks about his love of teaching and explaining difficult things. He shares how his teachers as well as Jules Verne’s novel L’île Misterieuse sparked his interest in science and convinced him that with science and engineering you can build a new world. 

The host of this podcast is’s Adam Smith, joined by Clare Brilliant. This podcast was released on 8 June, 2023.

Below you find a transcript of the podcast interview. The transcript was created using speech recognition software. While it has been reviewed by human transcribers, it may contain errors. 

Physics laureate Alain Aspect showing his Nobel Prize medal
Physics laureate Alain Aspect showing his Nobel Prize medal after the award ceremony on 10 December 2022. © Nobel Prize Outreach. Photo: Nanaka Adachi


Alain Aspect: People say, “Why are you wasting your time in doing that?” And I say, ”Do you give me 10 minutes or 15 minutes?” Yes. And in 15 minutes, I could convince a normal physicist that it was an interesting problem.

Adam Smith: I can’t guarantee that listening to this conversation with Alan Aspect is going to bring you a total understanding of the strange quantum mechanical world that he’s been investigating. When you use normal language to describe it, it’s just so crazy. The idea that two particles so widely separated in space that they can’t possibly be communicating with each other but are somehow linked just sounds like some kind of magical force from elsewhere. The system that he’s talking about is one that is only understood within the mathematics, the formalism of quantum mechanics. There’s always a disconnect between those who do understand quantum mechanics and those who don’t in such a conversation. But I do think Alan Aspect is so good at explaining what he does and such a good teacher that listening to him does give you a very good flavour of what it’s like to do research at the cutting edge of quantum mechanics. 


Clare Brilliant: This is Nobel Prize Conversations, and our guest is Alain Aspect, recipient of the 2022 Nobel Prize in Physics. He was awarded for his experiments with entangled photons, establishing the violation of Bell inequalities and pioneering quantum information science. He shared the prize with John Clauser and Anton Zeilinger.

Your host is Adam Smith, Chief Scientific Officer at Nobel Prize Outreach. This podcast was produced in cooperation with Fundación Ramón Areces.

Alain Aspect is a professor at the Institut d’Optique Graduate School and the École Polytechnique at Université Paris-Saclay, as well as a research professor emeritus at CNRS, The French National Centre for Scientific Research.

In the conversation you’ll hear him talk about his love of teaching, the joy of pioneering a field which many physicists used to dismiss at ”crackpot science”, and how to cook the perfect egg.

But we start, with the end.

Smith: I wanted to start by exploring this amazing journey that for you began with an idea in 1974. There was a dramatically successful experiment in 1982. Then 40 years later, you were in Stockholm receiving a Nobel Prize. If we just jump right to the end and think about how it felt to be standing in the City Hall in Stockholm, giving your banquet speech to the assembled 1300 people.  

CLIP from the presentation of the speech

Smith: What did it feel like getting to the end of a very long journey?  

Aspect: I think the feeling was the same as when I had to stand up to receive the medal from the hands of the king, having a thought to the young Alain Aspect opening a file in which there was the paper by John Bell. Being absolutely amazed by that paper. My friend Nicolas Gisin uses ”love at first sight”, the expression love at first sight. I think it’s exactly what happened. After one hour, I knew I wanted to work on that subject.  

Smith: How lovely to find your true love. So young. So early. Let’s begin to explore this so that the file that was handed to you. This was while you were trying to sort out what you might be doing for your PhD.  

Aspect: My situation was quite nice because I had a teaching position. I could do my research in any lab. I went from one lab to the next one asking for an interesting subject. At Institut d’Optique, there had been an experiment on so called one photon and difference experiment. I knew that that the professor who became my advisor, had been involved in this experiment. I asked him, would you have something of that kind? He gave me that file in which the first paper was John Bell’s paper. There was the thesis of Stuart Friedman and the thesis of Dick Holt. I first read the paper of Bell, I found that it was absolutely the subject I wanted to work on. There was a debate between Bohr and Einstein in 1935. Einstein, with his colleagues Podolsky and Rosen, considered the situation with two particles and realising that the formalism, the mathematical formalism of quantum physics allows for this so-called entangled state. From this, he concluded that quantum mechanics should be completed. Bohr disagreed on that. There was a debate between them until their death.  

Brilliant: Adam, I’d like to ask you about this debate, but first, is there a simple way to describe quantum mechanics?

Smith: The American physicist Richard Feynman famously said in 1965, “I think I can safely say that nobody understands quantum mechanics”. That’s a worrying start, but yes, quantum mechanics is the branch of physics that describes the interaction and behaviour of particles on the atomic and subatomic scale. So classical physics, classical mechanics as developed by Newton, for instance, describes very well the behaviour of things on the scale in which we live. Motions of planets and the way things behave when you drop them in gravity. It breaks down when you try and use it to describe the way that really small things interact like electrons and protons. For that, you need this new branch of physics, new at the beginning of the 20th century and still being developed – quantum mechanics.

Brilliant: The Nobel Prize was related to quantum entanglement. What is quantum entanglement, Adam?

Smith: The sad truth is probably that you can’t really talk about quantum entanglement unless you properly understand quantum mechanics. In the terms that I understand, at least, quantum entanglement is a phenomenon derived from quantum mechanics in which two particles can be separated by any amount of space, vast distances, and yet their properties are still linked so that any change in the properties of one will produce an instantaneous change in the property of the other. That is contrary to all we know about the universe because we understand that nothing can travel faster than the speed of light. Yet such apparent communication between two particles instantaneously would necessitate the transfer of information in a way that must travel faster than the speed of light. It seems paradoxical that this can happen, but from a quantum mechanical point of view, it’s perfectly fine. People like to say that quantum mechanics doesn’t care about space and time. This is a prime example of that.

Brilliant: But Einstein wasn’t happy with that. He felt that there must be something missing from quantum mechanics. Is that right?

Smith: Yes. For Einstein, this was a step too far. He, together with colleagues Podolsky and Rosen wrote a paper in 1935 in which he thought that what he’s termed this “spooky action at a distance” was not sufficiently explained by quantum mechanics and that quantum mechanics was somehow incomplete because it didn’t explain the phenomenon of entanglement. Others disagreed with him. Bohr, for instance, thought that quantum mechanics was perfectly sufficient to explain quantum entanglement.

Brilliant: Bohr and Einstein disagreed on this quite fundamental point related to quantum mechanics. Then a scientist called Bell came along a few years later and wrote a very important paper. What was Bell’s paper about?

Smith: That’s right. The debate happened in the mid 30s and then sort of just lay there in the record. In 1965, Bell published the first of his inequalities, which were mathematical proofs designed to test the thought experiment that Einstein had laid out in his 1935 paper.

Brilliant: A few years later, the young Alain Aspect came along and read Bell’s paper. What did he do as a consequence of that?

Smith: He and others, such as notably John Clauser, one of his co-laureates, saw Bell’s inequalities and realised that they laid a path towards experiments which could actually test whether quantum entanglement was a real phenomenon. They were tremendously excited by this. They could see that an experiment was possible. They set out on a path of experimentation, which after much development intellectually and technically, led, eventually, to Alain Aspect’s definitive experiment proving the existence of quantum entanglement.

Brilliant: This helped to settle the debate?

Smith: Yes, these experiments basically put the debate to rest. It’s very interesting to listen to Alain Aspect talk about the significance of the debate. Let’s listen to him.

Aspect: Mostly nobody cared for several good reasons, I think. The most important reason is that it was only about interpretation. If you are a young physicist, active, you use quantum mechanics, it works. It allows you to explain experiments or to discover new theoretical features. Why would you care about an epistemological debate between these two old glories. The real role of Bell is to have discovered that it is not only a matter of interpretation, not only a matter of epistemology, but that you can settle it. This is absolutely fantastic. I don’t know any other instance in the evolution of ideas, where a debate looking like a philosophical debate can be settled by an experiment.  

Smith: I begin to understand why you fell in love with this possibility.  

Aspect: I was absolutely struck. Now you have to realise that I was mostly impressed by Einstein. In my in my head, I am an Einsteinian. On the other hand, I understood the quantum mechanical formalism. For me, it was a totally open question, because I knew of the success of quantum mechanics. I could not imagine how Einstein could be wrong.  

Smith: When you say you understood quantum mechanical formalism, that understanding, I remember you mentioning when we spoke on the day that you’d been it was announced you received the prize, that understanding actually came in a strange way that you worked on it while you were a teacher in Cameroon.  

Aspect: Exactly. The point is that I am old enough that during my studies, I have an excellent classical physics education. But I must say that my education in quantum mechanics was extremely poor. It was not clear at all to me, what was the relationship between what they were teaching me and physics. I was frustrated of that. I knew that it was important. I was frustrated not to know it well. When the book of Claude Cohen-Tannoudji, Bernard Diu and Franck Laloë was published, I was indeed in Cameroon teaching, I got the book immediately. I really studied the book from page one to page 1300 or something like that. There is a big advantage of doing that. The book is totally neutral regarding interpretation. I’m sure that if you have a professor saying, well, this is not possible. Shut up and calculate. Shut up and learn. Then we will discuss later. But there was nothing like Shut up and accepted. It was just this formalism, and use it, and nothing else. I think it was very important. I have nobody to wash my brain, telling me that it was not interesting to think about this stuff.  

Smith: It obviously gave you great clarity of thought.  

Aspect: The book is fantastic. It’s known in the world, and it deserves it. I had a good mathematical education. It means that no mathematical formalism in the book was difficult for me.  

Smith: It’s quite rare to take time on your own to study in that way. It’s obviously incredibly beneficial in your case. But it’s hard to achieve that such space to think through something like that. You have to be quite disciplined under normal circumstances to do it. Certainly then when you were teaching in Cameroon, you had enough to be doing I’m sure. 

Aspect: Yes, but on the other hand, when you were teaching overseas, as I was, you are cut off almost everywhere. There was no TV, nothing else to do than reading. No family to go with during vacation. In fact, there was plenty of time of free time. Moreover between 12 and 4pm it was quite hot. It was better to stay home to wait for the heat to decrease. It was a moment when I was studying.  

Smith: Yes, some people might have just taken a little nap, a siesta. 

Aspect: Yes, but I was young at that time. I did not need any nap. 

Smith: Anyway, marvelous preparation for encountering Bell’s paper in 1974. Of course, it was a risky thing to undertake. It was a risky project. You told the story beautifully at the Nobel banquet of your first encounter with Bell at CERN.  

CLIP from the banquet speech

Aspect: I said, why are you asking this question? Then he tells me, oh, you know, doing this kind of subject, people are going to think that you are a crackpot. I did not know the word. I asked him to explain the word to me. He said, you know, most people think that the subject is not interesting. That one has to be crazy to embark into that. I said, but I have a permanent position, they cannot fire me. I have a job, I am teaching. I can spend my time of research as I want. He said, Okay, let us do science. Then he encouraged me. A few months later, I published the idea. It was with the recommendation of John Bell. When I visited John Bell, I asked him about publishing the idea. He told me that I should absolutely publish it. It was a very good advice, because nobody has any doubt that it was my idea. I am the only author of the idea.  

Smith: That’s very clever. You weren’t at all worried about anybody else going off and trying to do the experiment?  

Aspect: No, no, I was not worried, I was quite young. I was eager to receive advice. When I asked John Bell, should I publish it? He was very clear. He told me, yes, in fundamental science, you have to publish everything. Don’t count upon me to keep it secret. You tell me your idea, I will speak. It’s a good idea. I will speak about it. You better publish it. 

Smith: John Bell must have been thrilled to encounter a young enthusiastic, talented person who wanted to take this on.  

Aspect: John Bell was a cool person, not showing much feelings or it’s not to say that he was not a nice person, but he was not warm. He was very serious. Was he thrilled? No idea. What I can say is that we met quite often until the result of the experiment. He was part of the committee of my PhD thesis when I defended my PhD thesis. He always showed that he had a high respect for experimentalists. He clearly stated that he was unhappy of the result, but he did not discuss, the result is what it is. He would have preferred another result, but he had absolutely no nit-picking about details of the experiment. He was totally trusting experimentalists.  

Smith: Your PhD defense was in 1983. The 82 experiment, which is the experiment cited in the by the Nobel Prize committee – it was a part of your PhD and it’s quite unusual to do work during your PhD, which results in a Nobel Prize in such a ground-breaking discovery. It must have been quite a thesis defense, because of course, it was pretty apparent just how groundbreakingly important this work was. 

Aspect: Yes, the point is that the wind had been changing direction. Until 1978, 79, there was still this feeling that, oh, this guy is a crackpot. This is a guy who is checking quantum mechanics. Everybody knows that quantum mechanics works. Everybody knows that Bohr replies satisfactorily to Einstein, etc. But I must say, and I think that I need to have some credit for that. I found a way to explain what the goal is of Bell’s inequality. Explain that not to experts in hidden variables, but to physicists totally naive with respect to this question. People say, “Why are you wasting your time in doing that?” And I say, “But do you know what is the question?” They say, “No”. ”Do you give me 10 minutes or 15 minutes?” Yes. In 15 minutes, I could convince a ”normal”  physicist that it was an interesting problem. You know what happens? You are invited for a seminar. There is a one-dozen-of-person. But if your seminar is good and clear, there are people in the room that will invite. It’s just an exponential growth. In 1980, there were many people who would realise that it was an interesting subject and were inviting me. When I defended my PhD thesis, yes, the big auditorium of Institut d’Optique could not accommodate all the people who wanted to enter. There was no video at that time. The people were out.  

Smith: That was quite something to miss. It’s very interesting because it speaks to the value of being able to convey ideas.  

Aspect: Absolutely. In a sense, I think that part of my Nobel Prize is due to my ability to convey and to explain things. I am a professor. I am fundamentally a professor. I love teaching and explaining difficult things.  

Smith: That’s lovely to hear because so often people see teaching as being in conflict with their research. It gets in the way. It means they haven’t got time, but obviously not here.  

Aspect: No, another Nobel Prize laureate close to my building, Albert Fert, said exactly the same thing. ”It is by when preparing my courses that sometime I got to think deeply to the subject”. It’s the same for me. When I prepare a course, I think about the most difficult question that the most clever student could ask me. What should I reply? This allows you to go in depth in the subjects.  

Smith: What a lovely approach. It must be nice sometimes to get surprised by people who ask questions that are even cleverer than that.  

Aspect: Yes. 


Smith: Bell took the question out of the philosophical realm into the practical realm, if you like, if you take, go back into the philosophical realm, what you showed is going on does seem like magic. It’s that two things that are separated by vast amounts of space can be influenced apparently at the same time in the same way. It is hard to accept if you just think about the universe as we know it.  

Aspect: We have to distinguish the scientific or logical conclusion that we can draw and the kind of interpretation and image that we give of the conclusion. The conclusion is that the local realist description does not work. There are two important notions, locality, the fact that everything you can measure on one object in a given region of space time, everything is determined by properties, parameters, which are in that volume. This is local realism. There is a fact that nothing can go faster than light. I think that what the experiments show is that we have to reject both realism and locality. Then deciding that you could reject one or the other one is a matter of personal decision, I would say. I accept the idea that something goes faster than light. But I know that this is nothing more than an image to support my intuition. What I found is that this image is extremely fruitful.  

Brilliant: I think I might need some more help here, Adam. What does he mean when he says “rejecting one or the other is a matter of personal decision”?

Smith: I think what he means is that it’s very hard to give up on beliefs that you’ve held all your life. In order to accept quantum entanglement, you have to drop the idea of locality which is the phenomenon that things happen because of local influences. If I push you, you’ll fall over. That’s how the world works – we know that. Everything is dictated by what’s happening in the local environment and by realism I think he means the relativistic universe. In other words, a place where nothing can travel faster than the speed of light. In quantum entanglement two particles are apparently acting on each other – or interacting – over distances which mean that you’re totally outside the local environment. Those influences are happening in a very non-local way and they’re also happening at speeds which indicate that something is transferring between them at much faster than the speed of light. If that’s happening you then have to drop the idea of local influences and you have to drop the idea of a universe governed by relativity. Obviously as far as we know nothing can travel as fast than the speed of light and local influences still go on. It’s not that these things are really totally incompatible it’s just that in order to imagine quantum entanglement and to accept quantum entanglement you have to have a mental framework which rejects locality and, as he says, realism. Whether you can do that is up to you. In his case he can. He can inhabit these different worlds but I suppose that’s because he understands quantum mechanics and so it all makes sense to him. It’s a bit of a leap of faith I suppose on his part to say, “Yes, I accept quantum mechanics and I drop these other two principles for the moment”.

Brilliant: Clearly he’s not the only one who’s made that leap of faith because there are now many people trying to work out real-world applications that are a consequence of being able to accept quantum entanglement and therefore quantum mechanics.

Smith: Absolutely and I think people would probably be very cross with me for using the word leap of faith because it’s not a leap of faith, it’s a leap of fact I suppose.

Brilliant: Or acceptance.

Smith: It’s acceptance, yes. It’s a crossover between the science and the sort of the philosophy of the science. All of that comes down to absolute real-world applications like quantum cryptography which is only possible because you do have quantum entanglement because you can have information existing in two places at once instantaneously linked so that in theory you could have a particle code something at one location and decode it at another. There is no need for you, the operator, to be sending anything between the two and that is the basis of this new science of quantum cryptography.

Brilliant: Is this something that people are working on right now?

Smith: Working on very actively just like quantum computing. I don’t think it’s the case that people know exactly how it’s going to turn out, or how it’s going to happen, but they are certain it will be able to work. In that way, it’s a bit like Alain Aspect’s own reaction to seeing Bell’s inequalities that he was I think certain that you could do an experiment that would put quantum entanglement to the test. Didn’t really know how that was going to happen yet but was sure that if you set off on the path towards it you’d get there and that’s very much how the world is reacting to quantum computing that there will definitely be quantum computers but I don’t think anybody can tell you definitively yet how they’re going to work. It’s interesting to listen to Alain Aspect himself talk about one of the applications of quantum entanglement.

Aspect: I have an example, which is of a big interest in the famous quantum teleportation, which is a big issue, for instance, for linking one quantum computer with another one and transferring quantum information at a distance. When I think of the non-locality of entanglement, I immediately conclude that we absolutely need a good quantum memory if we want the scheme to work. Until the moment when we have a good quantum memory, the teleportation will just be true for principle, but not more than that. Once again, I can see that immediately by looking at the experiment and accepting the idea of a non-locality, then I am not a philosopher. I don’t know if the world is non-local or not. At least this image is useful for me.  

Smith: It’s very pragmatic, if you like.  

Aspect: Yes. I have no choice.

Smith: Yes. The way you think of it, and the way that physicists think of it, is not in conflict with  relativity. Nobody’s saying that you can transfer information, transfer anything faster than the speed of light.  

Aspect: There is something quite subtle about that. When you try to use the scheme to transmit information faster than light, you discover that the impossibility is strongly linked to the fundamental randomness of quantum mechanics. In a sense, it comforts Bohr position, which was quantum mechanics as its self-consistency. If you add anything, then it loses its self-consistency. I would say it comforts the self-consistency of the formalism, which I am sad in a sense, because I love so much Einstein, but I have to accept the result.  

Smith: You could live with a foot in both camps, obviously, it’s possible.  

Aspect: The same year, I got the Einstein medal and the Niels Bohr medal.  

Smith: Okay, that’s a very clear demonstration of being of both parties.  

Aspect: Exactly.  


Aspect: I think the real basis for my trust and love in science, and when I say science at that time, when I was a kid, for me, it was science and technology. For me, it was the same thing. I did not have any distinction between a fundamental science and technology. I think that this belief in the value of science and technology goes back to the elementary school teacher. Remember that it was sometime after World War II, I was born in ’47, and it was a time of progress, more comfort in houses, more vaccination and this teacher conveyed the feeling that thanks to medical doctors, engineers, our situation was improving all the time. Second point, this elementary school teacher would do some small experiments in the classroom, and I was always fascinated. When I think about it, I think that the profound reason why I was fascinated was the following: When you see this, it seems mysterious or strange or amazing, but then the teacher tells you an explanation, a rational explanation, and I think this is my way of liking science. I like to have an effect, which is surprising, and then I want to find an explanation for that effect. I think that the first people who influenced me were these elementary school teachers, and I must say that it was at the same moment that I was reading the book of Jules Verne, L’île Misterieuse and these of course were reinforcing me in the idea that with science and engineering, you can win everything, you can build a new world.  

CLIP with reading from L’Île Mystérieuse:

Smith instructed his companions in everything, and especially explained to them the practical applications of science. The colonists had no library at their disposal, but the engineer was a book, always ready, always open at the wished-for page. A book which answered their every question, and one which they often read. Thus the time passed, and these brave man had no fear for the future.

Smith: This is a story of a group of engineers and scientists who plummet from a balloon down onto an uninhabited island, and through the use of science, they survive.  

Aspect: There are some things which fascinated me. For instance, one of the find a grain of wheat. He says, “Oh, we are going to have a bread with that,” and the other one says, “Hey, you are crazy,” and then he explains the exponential growth. He says, “If this one gives us, then after two or three generations, we have enough wheat to produce our own bread.” There are plenty of notations like that based on the understanding, then you will be able to do something.  

Smith: Absolutely. A recent example of that sort of application of science is this book and the film The Martian, which people have liked very much, where this astronaut finds himself marooned on Mars and survives through the application of science.  

Aspect: Yes.

CLIP from The Martian

Aspect: I think that the result of that was that when I arrived in high school, I was eager to learn physics. Unfortunately, at that time, we had the first course on physics only at the age of 15. In the first year of the high school, we had only math and biology, geology, but not physics and chemistry. I was eager, I was waiting for it. I think it is as a result of the small experiment at the elementary school. I was lucky enough to have this fantastic professor that I named several times, Maurice Hirsch, who was absolutely exceptional. He gave me the basis of my culture in physics that I have kept all my life, which is when you want to describe things, you have to use enough mathematics to do it well, but not more. You must understand at which point you must make an approximation. It’s no longer necessary to be rigorous. This I learned at high school.  

Smith: Your own experimentation is infinitely intricate and requires endless tweaking and a lot of playing around in the lab. How does that translate into quantum computers that we hope to see around us?  

Aspect: There are several aspects to that question. The first thing I want to emphasise is that for me, I defended my PhD. I had settled a debate between Bohr and Einstein, which is not bad, and it was time to go to elsewhere, to another subject. Exactly at that moment, Claude Cohen-Tannoudji, the author of the book, who accepted to be in my PhD thesis committee.  

Smith: It was a grand committee you had.  

Aspect: Yes. He told me, “Look, I want to start a program on laser cooling of atoms. Would you join me? I have a position for you.” I accepted. I turned the page. This was ’85. In about ’90, a young student came during a conference, sat in front of me, and very politely told me, “Professor Aspect, with your entangled photons, we can do quantum cryptography.” I said, “What? Explain me that.” The young guy was Artur Ekert. Until this point, I had absolutely no idea that there could be any application to that. But from that time on, then I kept an eye on the progress in the so-called quantum technologies. Now, there is another way of considering your question. How could such a complicated experiment be translated into useful schemes? I think we have so many examples of that. My belief is that when there is a market, engineers are absolutely fantastic to making reliable experiments. I’m deeply convinced that when there is enough interest, the engineers are good at transforming a lab experiment into an easy to operate experiment. It is exactly the idea of several start-ups, which are developing quantum technologies. Just take one example in my institute. The start-up Pascal is trying to make an easy to operate experiment from the laboratory experiment of Antoine Browaeys, which is one of the most advanced quantum simulator in the world, but it demands a three PhD and two postdoc to operate. Pascal is trying to duplicate it in a way which is just push button and that you can put in a computing center. I’m very confident that engineers can do it if there is a market, For me, if there is no fundamental law telling you that it is impossible, it will happen. An example, gravitational wave detection. At the end of the 80s, I belonged to a committee which had to decide if France with Italy would invest or not in such detection scheme. At that time, it was clear that we have no idea of how long it would take, but personally, I voted for it under the same statement. There is no fundamental law saying that it is impossible. One day or another, it should happen. It did happen.  

Smith: Indeed, it did. As you say, it took an awful lot of engineers and an awful lot of thinkers to make it possible.  

Aspect: And ingenuity.  

Smith: Ingenuity. Let’s finish with ingenuity on a totally different level. I hear that you are, maybe obsessed is too strong a word, but you are interested in the ability to cook the perfect egg. 

Aspect: Who told you that?  

Smith: I was told that you like to make a perfect egg.  

Aspect: The perfect egg is a name invented by a cook. The point, because I experimented on it, is that if you cook an egg for one hour at 63 Celsius, then the consistency is absolutely unique. I like to do that. I bought a small equipment, which is like a lab equipment, but it’s done for cooking, it circulates the water and it keeps it at 63. I have checked that 62 is not the same texture and 64 is not the same texture.  

Smith: What is the texture of a 63 degree for an hour egg?  

Aspect: It is a texture in which the white is half solid but not solid and not liquid. It is in between. The yellow is soft. Then you need to accommodate it with interesting things. For instance, you can add some truffles, fois gras, and then the ensemble is delightful.  

Smith: Finally, we spoke about magic or rather I spoke a little bit about magic in terms of quantum entanglement. I understand that you also like the practice of magic tricks.  

Aspect: Yes. When I was 65, CNRS put me on mandatory retirement. I was unhappy with that. A good friend of mine, Thierry Giamarchi, who was professor in Geneva and a fantastic magician, told me, look Alain, you seem to be worried. As a birthday present, I can propose to start you in magic cards. I thought that maybe I would miss occupation, which is not the case. When I started, I was fascinated. I am not bad. But my specificity is the following. These magic tricks are very well documented when you belong to the community. The way it is described is standard. You do this, you do that. In order to be able to do the trick, you have to practice for weeks, hundreds of times because you need to have the finger just like a piano, you must have the fingers doing everything correctly. You have plenty of time to think about it. I think about the text relating to quantum mechanics. For instance, when there are cards jumping from the carpet to my hands, I pretend that it is a quantum tunnelling effect. When some cards are infected by other one, I say these bosonic simulation. I have also quantum teleportation in having a card going from the left to the right and of course, everybody understands that it is a joke. I think that it is pleasant that I do the same trick as a normal magician, but my text is different. I remember a conference on quantum cryptography, the big world conference on quantum cryptography in Paris a few years ago, with all the big shots from Peter Shor to Artur Ekert, Brassard etc. I was asked to do the after-dinner speech. Rather than doing a speech, I asked for a camera and I did the quantum tricks.  

Smith: Were you nervous that it wouldn’t work in such in front of such an audience?  

Aspect: No, I can tell you when I was most nervous in my life, it was in the Nobel banquet, when I asked to go up and speak to people who had been drinking and eating for three hours and a half. There I was really nervous, but it worked.  

Smith: It worked beautifully. I remember the applause. It was lovely. Thank you so much.  

Aspect: Thank you.  


Brilliant: You just heard Nobel Prize Conversations. If you’d like to learn more about Alain Aspect, you can go to nobel prize dot org, where you’ll find a wealth of information about the prizes and the people behind the discoveries.

Nobel Prize Conversations is a podcast series with Adam Smith, a co-production of Filt and Nobel Prize Outreach. The producer for this episode was Karin Svensson. The editorial team also includes Andrew Hart, Olivia Lundqvist, and me, Clare Brilliant. Music by Epidemic Sound.

You can find previous seasons and conversations on Acast, or wherever you listen to podcasts. 

Thanks for listening. 

Nobel Prize Conversations is produced in cooperation with Fundación Ramón Areces.

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Nobel Prizes and laureates

Eleven laureates were awarded a Nobel Prize in 2023, for achievements that have conferred the greatest benefit to humankind. Their work and discoveries range from effective mRNA vaccines and attosecond physics to fighting against the oppression of women.

See them all presented here.

Explore prizes and laureates

Look for popular awards and laureates in different fields, and discover the history of the Nobel Prize.