Telephone interview with Alain Aspect following the announcement of the 2022 Nobel Prize in Physics on 4 October 2022. The interviewer is Adam Smith, Chief Scientific Officer of Nobel Prize Outreach. Adam Smith: May I…may I speak with Alain Aspect, please? Alain Aspect: It’s me, hello. Adam Smith: Oh, hello. Hello. My name is Adam Smith, I’m calling from Nobelprize.org, the official website of the Nobel Prize in Stockholm. Alain Aspect: Yes. Adam Smith: Many congratulations. Alain Aspect: Thank you, it’s lovely news. Adam Smith: Quite lovely news. How did you receive it? Alain Aspect: Well, it’s of course a surprise because we know that there are so many outstanding physicists who deserve it and… Adam Smith: Well, it comes at the end of…I mean, not at the end, sorry… it comes as part of a great lineage of prizes in quantum mechanics… Alain Aspect: Yes. Adam Smith: …starting, goodness, ninety years ago with the prize in 1932. Alain Aspect: Sure. Adam Smith: That’s an extraordinary thought, isn’t it? Alain Aspect: Absolutely, and you know I think even to earlier times…Well, you know, ’22, yes you are right. ’22 is Einstein and Bohr, right? The same year. Adam Smith: Well, yes, and then… or ’21, I can’t remember. Alain Aspect: Yes. Adam Smith: And then…But then Heisenberg in 1932 for the birth of quantum mechanics. Alain Aspect: Yes, and then Heisenberg, and of course all these great names. Of course, I am very impressed because I’m certainly not at the same level as these people who have really totally changed the…the physics. But then I am proud to be of the same league, of course. Adam Smith: Indeed. And it really speaks to the robustness of quantum mechanics. Alain Aspect: Yes. You know, when I did these experiments testing Bell’s inequalities, at the end the conclusion is yes, quantum mechanics resists all possible attacks! In a sense, my experiment was trying to…to find a…a…a limit of quantum mechanics, and we didn’t find it. Adam Smith: Isn’t that…isn’t that extraordinary, what a creation by collective humanity. Alain Aspect: Yes, yes. Adam Smith: And also, the international nature of this prize to Vienna, and to you in France, and John Clauser in the US, speaks to the international effort that goes into all of this.
Alain Aspect: Okay, and it’s important that scientists keep their international community at a time when the world is not so…so nice, and where nationalism is taking over in many countries. So we have to do all efforts to keep scientists making international communities – there is no doubt. Adam Smith: It’s a…it’s a very important point. The…the…the…the phenomenon you studied, this quantum entanglement, is so weird. Alain Aspect: Yes. Absolutely, absolutely. And it’s so weird that as I presented in the Nobel symposium a few weeks ago, the fact that I am accepting in my mental images something which is totally crazy, which is nonlocality. Of course, I know that nonlocality does not allow you to send a useful message faster than light, but in my mental images, I have accepted nonlocality because otherwise I cannot even think of entanglement, except in the equations of course. But if I want to have an image, I put nonlocality in my image. Nonlocality is the fact that there is a kind of instantaneous relation between two objects, of course, something that Einstein could not accept. But he had realised that entanglement meant that. Adam Smith: Yes, this connection over unimaginably vast distances that is possible. Extraordinary. Alain Aspect: Yes. Adam Smith: And, of course, your work settled the debates between Einstein and Bohr. Alain Aspect: Yes. Adam Smith: So, again, the historical significance of your work is…is amazing. Alain Aspect: Okay, I am glad you say that, but there is one point I want to make clear. When people say “okay, the debate between Einstein and Bohr was settled in favour of Bohr”, I like to say that Einstein owes a great, great merit in raising the equation. And if nowadays we know so many things about entanglement and we want to use it for quantum technology etc., we must give the credit to Einstein to have raised the equation. So, for instance, I got the same year Niels Bohr Medal and an Albert Einstein Medal, and I think that it’s fair. There is not one who wins and the other one who loses. Bohr wins from a certain point of view, but Einstein wins because he spotted something extraordinary. Adam Smith: And it’s always important to challenge. Alain Aspect: Yes, exactly. Adam Smith: Well, thank you very much indeed. I notice something from your CV, which is that just before you did your PhD, you spent three years doing Voluntary Service Overseas in Cameroon. Alain Aspect: Absolutely, absolutely. And you should know that it was essential because it is a place where I studied quantum mechanics in its modern formalism, in the book of Claude Cohen-Tannoudji, who got the Nobel Prize in 1997, and I studied by myself during this Cameroon period the book of Claude Cohen-Tannoudji, Franck Laloë and Bernard Diu, and when I came back to France, I was ready to understand the various papers, Bell’s paper. Of course, John Bell, it’s a pity that he’s no longer there, but John Bell is a very important figure in that equation. Adam Smith: Indeed. Isn’t that interesting, that life propels you onwards, and sometimes you have to just stop and take time for reflection? Alain Aspect: Yes, it was exactly…when I was in Cameroon I was teaching, but I had plenty of free time, and I used that time to…I knew that my education in quantum mechanics was not good at all. You know, it was the old quantum mechanics solving partial differential equations. And the book of Cohen-Tannoudji, Laloë and Diu taught me where is the physics in quantum mechanics, and I was then ready to understand the discussion by John Bell, etc. Adam Smith: It’s a very important lesson for people listening, I think. Alain Aspect: Absolutely. Adam Smith: Yeah. Goodness, how do you feel about the prospect of all this attention that is focussed on you now? Alain Aspect: Aah! I will try to survive it. You know, my phone is ringing all the time, so I have set it down. This is why we have to go to a different phone in an…in an office. Adam Smith: Well, I’m very lucky that you took the time to do that. Thank you very much indeed. Alain Aspect: And I’m so happy, thank you very much. Adam Smith: That’s good to hear, lovely. Alain Aspect: Thank you. Adam Smith: Bye-bye.