Bonus Episode: Season 1 Highlights

In this special episode of insideQuantum, we look back on our first season and take another listen to highlights of the 12 episodes that made up Season 1. We've come a long way in such a short space of time - thank you so much to everyone who's listened and made our first series such a success. We hope you're looking forward to Season 2!

Featuring:

• Dr Yihui Quek
• Dr Philippe Faist
• Dr Lídia del Rio
• Prof. Román Orús
• Dr Elliot Bentine
• Dr Monica Kang
• Ieva Čepaitė
• Dr Tiffany Harte
• Dr Viviana Villafañe
• Dr Araceli Venegas-Gomez
• Dr Alba Cervera-Lierta
• Dr Stefanie Czischek

Transcript

Copy

Hi there and welcome to insideQuantum, the podcast telling the human stories behind the latest developments in quantum technologies. I’m Dr Steven Thomson, and as usual, I’ll be your host for this episode.

Today’s episode is something a little bit different. We’ve reached the end of Season 1, our first 12-episode run, and I wanted to take a moment to reflect on the journey that insideQuantum has been on over the last 6-9 months. Thanks to everyone who has listened and supported us – thanks to you, our first season has been a huge success.

I also have to say a huge thank you to the other members of the insideQuantum team. This project started with a mad idea. Thanks to the Unitary Fund -- who provide small grants to innovative projects in quantum technologies -- I was able to turn it into a reality, but as time went by, more and more people joined in to lend a hand. In particular, I have to thank Jessfor the art design, colour schemes and logo, Elies for invaluable organizational assistance and Jonas for editing several episodes – you can find out more about each of them on our website, insidequantum.org, and keep up with what else they’re up to. I also have to thank many other members of the Eisert group here at Freie Universität Berlin for support, suggestions, and advice, particularly the group of advance listeners who sent feedback on early drafts of episodes before they were made public. 

To celebrate the end of Season 1, I wanted to go back through our first twelve episodes and pick out some key comments from each of our guests. Each and every one of them had fascinating stories to tell and advice to give, and it was amazing to hear all about their different career journeys. This podcast would be nothing without our guests, and before diving in, I want to thank them all again for agreeing to take part in this project. 

Without further ado, let’s get started.

[2:01] 

In Episode 1, we talked to Dr Yihui Quek, who was at the time a Humboldt Fellow at Freie Universität Berlin, and has since moved to Harvard University. We asked Dr Quek about the big picture of how her research in learning theory could be used to advance quantum technologies.

🟣Yihui Quek : Mm-Hmm. So I think there’s the big, big picture, which is to build a quantum computer or working quantum computer. And then there’s the ‘big but not so big’ picture, which is kind of like an intermediate picture, which is to get a working prototype of something that resembles a quantum computer, and that’s the stage that we’re at now. And I think a lot of what I do is working in this intermediate picture. So what we have right now are not quantum computers, but we have quantum processors consisting of on the order of a hundred qubits. And of course, for a working quantum computer, you would need like much more qubits than that. I think to run Shor’s algorithm, you would need on the order of a thousand logical qubits, which is like a million non error corrected qubits or something like that.

🟣Yihui Quek : But the point is what we have now is much fewer qubits than what we want. And so the question is what can we already do with so few qubits? And a lot of what I do is revolving around that question. The thing is that with our current quantum processors – I’m gonna call them quantum processors because they’re not actually quantum computers. They’re so small and they suffer from a lot of noise. So it’s… I think when people were writing all these early quantum algorithms, they definitely did not bank on there being so much noise. And so a lot of quantum computation is built on the assumption that you’re running an error corrected quantum computer. And so my, the question I’m trying to answer is what can you do, even if you’re not running an error corrected quantum computer. And more than that, if you’re running a super noisy and super small quantum processor. So I use concepts from classical learning theory, classical statistics and information theory, both quantum and classical to kind of answer this question. And it’s a really interesting question that sits at intersection of physics and computer science, because you need physical concepts to understand how quantum mechanics works in the presence of noise. And you also need computer science to kind of like figure out how to make that into an algorithm or what kinds of limitations you can expect in this kind of regime. Okay. So I really enjoyed that.

We also make a point of asking all of our guests – regardless of their gender identity - about equity, diversity and inclusion in physics, and their experiences throughout their career. The responses have been fascinating, particularly in how things differ between countries. 

🟣Yihui Quek : And in terms of social attitudes, I’ve also noticed a difference between America and Germany. So I think in America, or at least in California, there’s a lot of talk about diversity. And the reason for this is that I feel that in America, demographics are quite central to people’s identities. So people are always very conscious of like what race they are, what gender they are. And they’re very conscious about the history, about the historical background of their ancestors, as well as the challenges that people of the same identity as them are currently facing. And this comes up a lot in conversations in America. Whereas I feel that it doesn’t so much here in Germany, and I think this may have something to do with the fact that many people in America have immigrant backgrounds. And so I think it’s fair to say that it really is a more diverse place.

🟣Yihui Quek : And so that’s why there’s more opportunities for these different identities to kind of rub against each other and potentially cause conflict so that’s another difference I’ve perceived. And I think it would kind of be, I mean, I would prefer to see more, more considerations of people’s identities in Germany as well. So yeah, for example, I think this is one of the other questions you were going to ask me but I noticed that, especially in, in physics, it tends to be very male dominated here in Germany and I think that I didn’t really notice this when I was studying in America because like I think there’s more efforts to kind of promote diversity in the workplace in America. I mean, it was definitely still male dominated, but the generation wasn’t as extreme as it is here.

We like to end every episode by asking our guests what advice they would have for others in the field, and this question evolved into asking our later guests what advice they would give to a younger version of themselves. 

🟣Yihui Quek : I think what comes to mind are two pieces of advice. The first is that you have to be unoffendable. So I think I’ve noticed at least in myself, that I used to be very conscious of or self conscious about how I was perceived. And this would kind of be a barrier to me, really expressing my thoughts on a particular thing. And it was a very stupid barrier because it prevented me from learning properly because I would feel, oh, this question I’m about to ask sounds so stupid. And I don’t wanna ask the question and because I didn’t ask the question, I didn’t learn, but I think nowadays I’m becoming more and more unoffendalbe, which means that I no longer have this barrier. And I say what I’m thinking, even if I think it sounds stupid.

🟣Yihui Quek : And the second piece of advice is kind of always be very conscious of the environment that you’re in. I think I did not understand the importance of placing myself in a good environment when I started my PhD, but I slowly learned that applying a strict filter on my environment was one of the most effective and efficient ways of improving myself as well. Because when you’re surrounded by people who are positive, hardworking, and who enthuse you, then you find that you become one of these people as well. So if you just put in the effort at the start to select the right environment for yourself, then that can save you a lot of effort later on, namely the effort of kind of like making yourself excited about your own research, which can be very difficult when you’re kind of in a place where no one else cares or in, or if you’re in a place where like there’s a lot of hubris and people are kind of like always talking over each other and it’s very antagonistic. So always try and avoid these environments and go to positive and constructive environments instead.
 

[8:39]

In Episode 2, we talked to Dr Philippe Faist, also of Freie Universität Berlin. Why did we talk to two people from the same university? Well, because it’s the university where I work, and it meant for the first few episodes I was talking with friends and colleagues, which was a little less scary than approaching strangers! Dr Faist works on a variety of things, but we focused in particular on quantum error correction. What is error correction? Here’s what he had to say.

🟣Philippe Faist : Great question. Let’s go back to your example of the repetition code, where I just repeat my information for a classical error correction. Well, in that case, if I repeat each letter or each word three times, for instance, then that will mean that I will have to triple the size of the information that I’m sending to you. If I want to convey a sentence of 10 words, I will suddenly have to send you 30 words to be able to convey that information. Well, it turns out that there are codes that are much more efficient so that maybe I would only have to send, and I don’t know, 15 words instead of 10 to redundantly encode the information in a way that protects it to a similar level of protection to what I would get with the repetition code. So that’s one example of a better code than the repetition code in terms of the encoding size.

🟣Philippe Faist : There are many parameters on an error correcting code that we might be interested about - many features, if you like. So first is how many physical carriers do I need to encode a given amount of logical information. Then there might be how robustly protected the encoded state is, how many carriers can I lose while still being able to recover the information? Then there’s another aspect which is, can I encode to the state and can I decode it easily? You might have a very good error correcting code, but if it’s really hard to encode or decode, that might not be a very interesting thing to do. So you have all of these parameters and they trade off. You know, they’re sometimes you have codes that are very good at encoding lots of information, but they might not be very robust to losing a lot of physical carriers.

🟣Philippe Faist : So one of the reasons you have this variety of error correcting codes is that they kind of all specialize in different features and some codes are good at one thing, some other codes are good at something else. Maybe one code is simply very easy to describe, and that might be even useful just for pedagogical purposes, if you’re teaching error correction. So, you know, there is a huge variety of error correcting codes that trade these different parameters off. And then there’s another reason why you have so many codes, which is it’s still a very active field of research. People still realize that there are new things to be discovered, new, better codes to discover. And to give you an example, even classical error correction has new results coming out. I mean, 10 years ago or so there was a discovery of the polar codes, and that’s now the technology that’s being used, if I understand correctly, in 5G networks. So you do have a lot of progress going on also at the classical level, even though the field of classical error correction has been there for very long. And of course, quantum error correction is a much younger field and it also has a lot of new research coming out every day. It’s a very active field of research with a lot of new results, all of these new results, they generate new codes and you kind of make your field of error correction bigger.

We also asked Dr Faist what advice he would have for people interested in getting into the field, and he stressed the importance of networking and making connections with other researchers. Science, after all, is done by people, and none of us work in isolation.

🟣Philippe Faist : You know, what makes it tricky is that every career path is extremely different, you know, in academia or in research, especially in our field, you can do so many different things. Nowadays, you can go do an internship at a quantum company…that wasn’t really an option when I did my PhD. So, you know, if you’re a PhD student and you want to get into research and quantum information, it’s a lot about, you know, getting to know people, getting to know…networking, going to conferences. I think that’s a, I think we’re a field that has still a lot of new ideas and concepts that are to be explored. And even the, the technical tools, the foundation of, of our field are still evolving to a good extent. It’s still a very young field. So I think there is definitely room for new ideas and for new approaches. And don’t be shy of trying to think big and try to put your own mark and network with people, go to conferences.

[12:56]

In Episode 3, we spoke with Dr Lídia del Rio, a researcher at ETH Zurich and a co-founder of the relatively new community-driven journal Quantum. This was our first remote interview and there were quite a few technical issues, which I hope were not too obvious in the final episode!

We started by asking Dr del Rio about her work in quantum information theory, and just what information theory actually is.

🟣Lídia del Rio : Right. So I guess information theory treats how information flows, how we can encode a message. How we can encode, like communication, how we can formalize this, and then all sorts of questions. Like from how can we send a message securely or the cryptography part? Or how can we compress an image so that it can be sent on your phone very cheaply right? And then quantum information is like, oh, and what if we couldn’t code this information in the state of quantum particles of electrons? (For example, or photos or whatnot). And, you know, this could be, it could be a very simple question, right? Like, oh, why can’t we encode information in…I dunno, smoke signals, right? But what makes it different is that then the rules are really different compared to a classical information series. For example, you cannot just copy a message. It allows you to do more things that you cannot do classically and there’s like a whole new range of applications you can do from here.

And then this goes into many directions, right? One is quantum computing, which is what if we can write programs that run in, on quantum particles and does it give us any new power? And, you know, it does as far as we can tell so far. But also foundations of quantum physics, if we just now, Okay, so what if now we try to study physics from this information perspective, right? Instead of thinking of just modeling a system, let’s think about the information flows about … Even thinking like, oh, this quantum physics restricts our ability to communicate. And can we go from these kinds of information principles to derive all of physics from here? So that’s more the direction that I’m studying now.

The other main topic we discussed was the community-driven journal Quantum, what it does differently from other scientific publications, and Dr del Rio’s role in co-founding this new journal.

🟣Lídia del Rio : So I, I didn’t do it alone. That’s the key part, we are three co-founders. So it’s me, Christian Gogolin who is now at Covestro in Cologne and Marcus Huber, who is in Vienna. So I heard, I was in Bristol as a postdoc at the time. And I heard from a colleague that the two of them whom I knew had been discussing at some conference, maybe the need to create a journal. So I got in touch with them. This was kind of February, 2016. And then, you know, sometimes there’s good chemistry with people. So we clicked very well. We agreed on the basic principles. We found the platform for peer review right away. And then once we got the tour of this platform, we’re like, okay, we’re on, we don’t have any excuse not to do this . So then we started, it was, it was very quick.

So the first thing is that we had to set up all the legal and admin things. So we had to register an non-profit association, which would be the publisher of the journal. We created a website for a journal and then we were still preparing this a bit and just, you know, chatting with colleagues now, and then about this idea when suddenly it went kind of mini-viral in the community because someone leaked this to Twitter. Ah, and we were not ready at all. But then, but then we did … I think we did something clever, which was to, okay, we are gonna involve the whole community, the whole research community in this. So we, we published through various social media that we were preparing  this project, and then we held kind of open discussions.

I think we even used Reddit at the time for… Look, here’s the proposal for the, the statutes of the journal. Here’s the proposal for the editorial policy. Here’s a proposal for the code of conduct. Here’s a proposal for the scope of the journal and so on. What do you think? Right. And then we held these discussions for about a couple of months. And after this, you know, not only we had a very good structure already to start from, but we also had a lot of publicity so so from here, so we had all the legal part taken care of. We had the bank account with nothing there. I think, I think Christian at the time put 2000 euros there as a starting donation. And then we, we ran an open call for editors. No, no. Before this, we, before this, we invited people… We wanted to have a steering board.

🟣Lídia del Rio : Exactly yes. Yes, exactly. So this, they also suggest new policies. So we wanted to have separation of policies. So the founders, the three of us me, Christian and Marcus. We are the executive board. We take care of all the admin and more than this, but the, the editors are responsible for taking care of individual papers. So they have, they’re the only people with editorial power of any kind, right? We cannot influence them. And the steering board decide the overall policies. And, you know, they also select the new editors. Every time we have a call for editor, for example, they suggest new editors. When you say, oh, we need someone new in quantum optics, for example. Yeah. So first we invited the steering board and the way we did this was first reach out to people who are very senior scientists who know us, right? We’re all working in quantum thermodynamics, which is relatively niche, but, you know, then we invited and Andreas Winter and, and Rob Spekkens who are quite well known in the community. And that is reached to people also in quantum physics. But maybe that we did not know personally, but you could tell them, oh, look, these big shots are already backing this idea. So , do you want to back it to right? And, and like this, we, we, we got the steering board of 14 people, which was … We’re very happy because it had very good gender diversity and also some geographic diversity and, and also diversity in fields of expertise. So this is good. And then when we then launched the cultural editors, not only we had had already all these discussions in the community, so people were invested in the concept of the journal, but they also knew it had the backing of these, of these senior researchers in the field. So it was a serious thing.

🟣Lídia del Rio : So we wanted that from the moment we accepted publications, it would cover all of quantum physics, right? Maybe the people started from our relatively small field and then rapidly expanded by the, by the time we started, we opened for publications. It was already covering the whole field. So if, if the listeners know the arXiv, this is everything that’s published in quant-ph, which is quantum physics in general should, should be able to be published here.

We also discussed the advice Dr del Rio would give to a younger version of herself, and here we touched on a topic that I’d like to focus on even more in future interviews: the importance of mental health in academia. 

🟣Lídia del Rio : Right. so here, I don’t think I would give myself advice about career in general. But what I would tell myself is, look, it’s not, it’s not normal to struggle so much with the things you struggle with. And you should go and see a mental health specialist and get diagnosed. So I found out last year that I have ADHD and it’s like suddenly the last 10 years, the last 20 last 30 years makes sense. You know, it puts everything in context and there’s just so much suffering associated with work and work struggles that come from this, like, you know, I was a kid who never did their, their homework, but would always get away with this because, you know, I was smart and I’d get good grades. So it, it’s not something that was ever a problem. Like even at university I would study the night before the exam and then you know, still have very high grades.

So although I would always tell myself I shouldn’t do this and I would like feel guilty and all these things you know, it was never a big problem until, you know, until essentially the pandemic hit and all my coping strategies went out of the window. And there’s just so much that could have been avoided if I’d known what ADHD was before, what kind of problems it causes and what kind of, you know, management strategies and medication exists that really make your life better. So I wish I could have given myself this advice and I wish people who struggle. So like if you’re listening and you always struggle to meet deadlines, but you’re still very smart or, or not, or you think you’re not yeah. Maybe get yourself checked.

[22:15]

In Episode 4 we took our first step a little outside of academia and spoke with Prof. Román Orús, a research professor at the Donostia International Physics Centre and also a key figure in Multiverse Computing, a startup applying quantum-inspired algorithms to real-world problems. Prof. Orús has had an interesting career spanning several different fields, so we asked him whether this was a conscious decision or if it came naturally.

🟣Román Orús : Yeah. The overlap came naturally. Actually I, when I started doing research in my PhD, I started doing quantum information and quantum computation, but by that time, you know, since the hardware was, was not so developed the field of quantum information was full of, of people that at the end of the day, somehow diverted and started doing in parallel also condensed matter or quantum optics or even high energy physics. The point is that there is, there are natural overlaps between all these disciplines. Okay. And for me, it was very natural to, to work on, on both of them. So I, I always thought that I had one leg on quantum information and one leg on condensed matter physics. Okay. And, and everything that I was doing in condensed matter physics, it was useful for quantum information and the other way around. So I was…one of my, my research lines was to understand entanglement structure in, in quantum many systems.

So, you know, there are quantum correlations and so on, the ones that are used for teleportation and for quantum key distribution and all this very nice you know, quantum technology protocols, but the, the whole point was, well, how does this behave in a quantum many system? Because of course there is entanglement that, and there you start playing with phases of matter and so on. And it’s really an interdisciplinary field. It’s not that you can set very, very defined boundaries between fields. Okay. Actually, lots of results in quantum information that are very useful for condensed matter physics and also the other way around.

We also asked Prof. Orús about the near-future goals of his work.

🟣Román Orús : Yeah, well actually I would say supporting the development of a quantum computer and also the applications of a quantum computer as, as this right now you know, there are many…and also the investigation of, of new algorithms. Okay. So these, these new algorithms can be useful for many things. They can be useful for understanding phases of matter, okay, which is an open problem. But they can also be useful for understanding other types of, of physical problems and even for applications beyond, beyond physics. Okay. So, cause at the end of the day, if one has a quantum computer, you want to use it for something and, and you need to find applications in other fields, no. Also in industry, you know, how are you gonna apply a quantum computer to solve problems in finance, in energy, in, you know, material science, in health and so on?

Right now my current research goes a little bit along this direction, so how to develop applications and new algorithms for, for quantum computers. Okay. But also of course also using all this knowledge that we already have, and that we have accumulated over the years of, of all these numerical algorithms that we know for, for quantum many body systems. Okay. This is extremely useful, but it’s nice is that all these algorithms that we have been applying to study quantum many body systems over many years, now it turns out that we cannot supply them for instance, to improve machine learning. Okay. Which is an extremely, let’s say transversal tool. You can apply it to essentially everything or to optimization problems, and then you can mix it with quantum computing and so on.

We finished by asking Prof. Orús about his advice for anyone wanting to get started in the field, and he stressed the importance of finding something that you love doing.

🟣Román Orús : Well work a lot. . Yeah, no, but I will say that if, if you have a clear idea of what you want to do and you really like it, okay. You, you really like, you really need to like, and to love what, what you do, because you know, you’re gonna spend most of the time in your life working and you better like your work, or better don’t do it because and that’s, that’s very important. You must have fun. I always told that to, to my students when I was teaching in mind. And and I still here I have a research position, so I’m not teaching, but I still say that to everybody, if, if you are not having funding for two or three days in a row, then there is a problem. Okay. So so you need to, to really like what you are doing.

And then I will say that, well, you know, keep tuned to all these opportunities that are happening, study and work very hard. Quantum machine learning, optimization…machine learning is very useful. Okay. Quantum computing is also very useful. Try to have as much background as, as you can. There are lots of free courses, lectures, and so on, on the internet that you can do. And then they just give you a very good background on top of whatever you do at the university. So I would just try to go for all these free resources also say, and, and keep an eye on what is moving and, and also don’t be shy. So, I mean just go for it, have ambition, try to, to go in the direction that you want to go.

[27:08]

In Episode 5, we spoke to Dr Elliot Bentine, who was at the time an experimental physicist working with ultracold atomic gases at the University of Oxford. We began by asking what are ultracold atomic gases?

🟣Elliot Bentine : Okay, so ultracold atoms, obviously the, the most obvious thing in the name is the cold temperature. And I guess, firstly, we should ask, why do we need to have things that are so cold in the first place? The kind of physics that we are interested in is predominantly quantum mechanics and the reason that we want to go so cold is basically that, in quantum mechanics you have this quantisation of the energy levels of the system. And obviously that’s a true behavior of the universe all around us, it’s just that normally the splittings of those energy levels are so small that the energy scales we are used to in a classical world…we can’t resolve them. It’s like the graduations on a ruler are too fine for us to see. So what we do is we make the temperatures much, much colder and in doing so, what we’re really doing is reducing the energies in the system – the characteristic energies that are involved – until our system then reaches a state where those energies are comparable to the splittings so that we can begin to make out the types of changes in behavior that occur when something is dictated by quantum mechanics, rather than by classical physics.

And once we cleared that up, we asked Dr Bentine why ultracold atoms are useful:

🟣Elliot Bentine : So I guess there’s two separate aspects to it. One is that when you’re looking at the level of individual atoms quantum mechanics is present in almost every part of…what you can do with those atoms. For instance, quantum mechanics will be present in determining the energy level structure. That then dictates how you can interact with the atom, whether you can use magnetic fields to perturb the atom or optical fields, what kinds of fields you can use, you know, whether the different polarizations or frequencies they are, et cetera. So I think one part of it is that the atoms have a very high degree of sensitivity to external fields, depending on whichever state they may be, because you have an ability to measure, for instance, the energy separation between two energy levels to a very high degree of precision. If an external field were to change that energy level separation, it would allow you to basically determine that to a high degree of accuracy. What that external field is…because effectively you have a way to, you know, if you can very accurately measure what this separation is, you can then look for very small deviations in it. And therefore that gives you a very, very precise ability to determine what the external field is.

You might have noticed that I introduced Dr Bentine at someone who ‘at the time of recording’ was at the University of Oxford, and that’s because since then he has left the university and launched a new venture in medical physics. In many of our other episodes, we’ve mostly focused on the positive aspects of careers in academia, but it’s important to discuss the problems and issues that still pervade academia, which Dr Bentine described to us in the following way.

🟣Elliot Bentine : I mean, my own personal view is that I’ve sort of largely given up on, on academia just as a…as an entire culture, basically. I mean, that, that’s somewhat, you know, my reasons for basically leaving physics in the near future. Like, it’s very reluctant to change. I don’t have the answers of how to fix it. And personally, I’m really tired of it and I just sort of feel, I just can’t really carry on working in it so, yeah, I’ve sort of taken the decision to leave academia basically and, and trying and do research a different way. That’s not what I was thinking of doing a few years ago, but I don’t really…I know I feel at some point if I stay, I’m just sort of enabling the culture, you know? The culture exists as long as there are people around to sustain it.

And I dunno, gender imbalance is obviously one important thing. It is just very white male dominated at the moment. You know, there’s all kinds of groups who are very poorly represented in physics. And I don’t know how to fix that or change that. So some people will claim for instance, that that’s down to, you know…effectively access needs to be made sort of earlier on in people’s careers to get them into physics. But also, I’ve seen enough of people having horrible times within academia and within physics to feel a little bit of like, well, you know, if it is broken and it’s not gonna give people opportunities, even once they’re actually in it, then am I actually doing something of a disservice encouraging people to just throw themselves into a, into this like completely broken system?

These are quite sobering words, and I would definitely encourage anyone listening to reflect on their role in the culture of academia, and whether they could be doing more to challenge inequality and discrimination on a daily basis.

[31:57]

In Episode 6, we did something a bit different again and we spoke to Dr Monica Kang of the California Institute of Technology. Dr Kang was our first guest who didn’t work on quantum systems, but in fact studied gravity and high-energy physics. So why did we invite her onto a quantum technology podcast, and what does her research have in common with quantum physics?

🟣Monica Kang : Right. So think of it this way. So we have the universe and you want to understand it in every possible way. And I was saying that we take quantum fuel theory as a language to take to describe anything, but we can probably try to understand where the regime is kind of semi-classical in the sense that gravity is still fixed as a metric, like in a way the gravity is there and all the rest of the particles are fully quantum interacting. So it’s a like semi classical setting to understand our bulk, but quantum interaction. So it’s quantum mechanics still intact. And to try to explain that it’s like a borrowed concept with quantum field theory at first was Wightman’s axiom, which led to Reeh-Schlieder theorem that I think it’s also familiar to quantum information theorists, for a lot of them. It says that you act on, um, some operators in the open region of the space time, like some open region, let’s say, then you act with all the operators onto the vacuum, then it creates the whole different type of states, right?

And those states will then form to be still dense, uh, Hilbert space in that region, meaning that there will be ridiculous amount of entanglement that can be present. And that in quantum field theory, entanglement is unavoidable. Now entanglement entropy really sounds like it’s a more information theoretic type of object. Of course in universe, you can measure many things. It’ll contain many different informations, and information encodes our matter…by matters, I mean like all the particles in the universe and everything. So in that way that we are having interacting entanglement as a fundamental quantity, we can look at to encode these information and it brings up another viewpoint to see and analyze the universe in that fashion.

So in other words, it turns out that there are deep connections between gravity, quantum field theory, and the field of quantum information and even error correction, as we discussed more in the full episode.

We also asked Dr Kang about her experiences of EDI work in the United States:

🟣Monica Kang : Yeah, there’s a overall difference. So as a woman researcher, it’s been always rare to see another fellow woman. That’s something that would be great to have and more understanding of that would be great, because I’m sure different perspective is not just built in university. It’s probably built in over the entire of your lifespan, that’s how you approach anything in life. I think that’ll be very useful to incorporate into, I am sure people are not trying more hard to see what would be the right way to include diversity together. I know at least at Harvard where I did my PhD studies, they have been thinking about it and in live discussions. So I guess that’s a start. I think having, um, BLM movement and #MeToo movement would probably give something good in the end that academia will be more open to everyone and can be accepting of more perspectives. I’m sure it’ll be more fascinating in the future so that it’ll be better, faster and new ideas. I think that’ll be probably in progress. Yeah. I’m not a person who’s in admitting or anything. So I don’t know what’s really directly going on like now, but I’m sure there’s like a different overall directions that people are taking. So it’ll probably lead to more diversity in science.

Dr Kang also left us with some advice for other early career researchers:

🟣Monica Kang : I would’ve said whenever you think it’s very difficult and looks not possible, it will work in the end. Just you’ll have to find another way. Don’t stop trying.

[37:05]

In Episode 7, we spoke with Ieva Čepaitė, a PhD student at the University of Strathclyde who’s managed to pack a very diverse career into a short space of time. We asked her to describe what she’s currently working on as part of her PhD research.

🟣Ieva Čepaitė : Yeah, so the stuff I’m working on in my PhD right now is quite practical. I’ve done some work on what is called adiabatic quantum computation. So, this is a way of doing, of solving optimization problems on quantum computers. And we were coming up with ways how to make these things more practically implementable, how to speed them up so that you can deal with problems that arise when these things are run too slowly, which is your qubits decohere, they lose information. So things like this. I’m also working on very sort of high level theoretical ways to speed up, for example, measurements in cold quantum computers. So that’s very specific, very applied to a particular quantum technology, but it’s still something that’s geared towards quantum computation or at least some form of quantum simulation, at the end of the day. Stuff I’ve done before is quite different, it was more on the computer science side, rather than the physics side, but it’s generally geared towards making quantum computers more practically approachable and available.

🟣Ieva Čepaitė : Yes, yes. When I first started out in Edinburgh I was working on things to do with quantum cryptography. The group I was working with was quite into quantum verification protocols and things like that. So these are very highly theoretical computer science type things that people worry about. And during my PhD now I’ve started working more on the physics side, but still very much theoretical problems.

We also talked about near-future quantum computing, and what it means to be in the ‘NISQ’ era – that’s ‘N-I-S-Q’, for ‘noisy intermediate scale quantum’.

🟣Ieva Čepaitė : Yeah, so NISQ is an interesting term. It’s something that implies that we can’t yet do very large scale quantum computations, which some people assume is required to actually show any sort of advantage in using quantum computers over classical machines. So NISQ is a bit of a contentious term. However, at the same time there is potential, given the size of the systems in NISQ. So, NISQ means like, as you said, noisy intermediate scale. And what that means is that we have enough qubits that…presumably if they all work well enough, we can already show some advantage over classical machines, but that’s with the assumption that they work well enough. And it’s a big assumption. So I would say that my work is…I wouldn’t say independent of whether we have NISQ or not, it should be useful regardless, but what many people are attempting to do now with relation to what I said about engineering and experiments, not quite being there yet in terms of giving us big enough or powerful enough quantum computers is how do we exploit the technologies that we do have these technologies that are what we call NISQ that are sort of a bit small, but potentially big enough to do something interesting.

How do you mitigate the problems that come with not having what we call error correction, not having large enough quantum computers to have them work properly, to have them do really, really big problems. How do we exploit things that are technically too small, but perhaps not. When I think about my work, it relates to this idea of quantum simulation, which maybe we’ll talk about a bit in a second, wherein we try to bypass quantum algorithms or things that people develop to be run, let’s say on any quantum computer, if it has the right operations, if it can do this operation, that operation, but we rely instead on just having some quantum system that can do some things. And we see given those things, is there some useful amount of information that we can extract from it? So that system can be a lot smaller than we need in theory for surpassing NISQ, and that’s, that’s kind of the main idea behind quantum simulation. It’s like the difference between an analog computer and a digital computer. You can program very, very specific things on an analog computer, but definitely not any algorithm, whereas on a digital computer, you can program any algorithm, but you also require it to often be more powerful than the analog version, if that makes sense.

This was also the first time we had a chance to talk to someone very early in their career about equality, diversity and inclusion, and how the field looks to people who have only gotten involved recently.

🟣Ieva Čepaitė : Yes. So my experience has been pretty normal. I’d say I’ve not had any sense that I’m not welcome or that my gender has anything to do with my abilities perhaps in science or anything like that. At the same time, it is true that the less examples of people like you, you see in higher positions, the more difficult it is mentally, I think to convince yourself that you belong there. So it’s, it’s a very difficult topic to broach in general, because there’s so many complex things that go into it. I feel like obviously the, the fact that STEM is, is dominated by white cisgender men on average is a historical artefact. And we’re not that far from the age where no one but men was allowed into, say physics ,that I would expect, you know, a massive change to be visible, but there is a change.

There’s obviously been an increase of women in physics. And there’s definitely been an increase of people from various backgrounds and from various races. Whether or not this will persist and how long it will take for, you know, this, this change to become more visible. I really don’t know. It does seem like some people still have a harder time than me, and it depends on what environment they’ve landed in. I do think at least a part of it, and this is important to mention, is not down to, let’s say, higher education, as much as it is down to the influences you feel growing up from very little up to, you know, when it comes time to make the decisions, whether you wanna do, let’s say a physics PhD, and those factors are much harder to control no matter what you do. So it’s, it’s an interesting topic.

It’s one that probably requires many, many hours of discussion and investigation, but if I were to conclude, I’d say it is getting better. It’s hard to say how quickly or whether this will continue necessarily, although I think it will. And I think I would encourage people within groups if they have anyone from a minority there, part of the group, for example, if, if you are a guy in a you know, physics PhD, and there’s one girl in your group, to kind of perhaps be aware if there is any sort of…if, if the environment feels maybe unwelcoming in any way to people who are different, because these very small things do tend to contribute, in my experience, you know, little comments and behaviors. But other than that, nothing much to add.
 

[44:53]

In Episode 8, we heard from Dr Tiffany Harte, a Senior Postdoctoral Researcher at the University of Cambridge, and also a member of the AION collaboration, similarly to Dr Bentine who we spoke to in Episode 6. (A small peek behind the curtain: we actually contacted Dr Harte and Dr Bentine independently, and only later realized they in fact worked together. Science can be a small world sometimes!)

We asked Dr Harte about how ultracold atoms can be used to make ultra-precise measurements that might even help us to detect gravitational waves and dark matter.

🟣Tiffany Harte : Absolutely. So I’m an experimental cold atoms physicist. So, we cool atoms down until they’re a few hundred nanokelvin. Our goal for our newest experiment is to get even lower down into picokelvin. So just billions of a degree above absolute zero. And once atoms get this cold, all of their quantum properties really start to emerge. So you can build, for instance, one of my experiments is in quantum simulation. So the idea here is that we’re building a very highly controllable, fully quantum mechanical model of other systems. So in our case, trying to simulate the behavior of materials with certain geometric structures and because you are working with atoms, building up this experimental model of a system that in reality is made up of electrons moving around in a potential created by ions. The atomic system is much bigger.

(08:43): It moves much slower. It’s much easier to measure, and it’s very controllable. And on top of that, you’ve got all of these quantum properties that are emerging because you’ve got the atoms so cold. So you can really use this as a platform for simulating the behavior of complicated quantum materials. So that’s one aspect of the cold atom field and it’s increasingly branching out into lots of different application areas. The other experiment that I’m building currently is using atoms for quite a different purpose. So, still cooling them down: we want them to be extremely, extremely cold, extremely easy to control. When I say “easy”…relatively easy to control, and we want to perform atom interferometry. So the idea being that we split a cloud of atoms, let the two halves sort of create superposition of states - two states separate in space - and travel different paths, and then recombine those atom clouds and read out the interference between them, and that interference pattern will tell us about how those two different arms of the interferometer have evolved.

(09:59): So if they’ve experienced anything differently in the way that those atom clouds will evolve in time. And so we can use this to make extremely precise measurements of anything that will change the evolution of the atom cloud. So whether that’s tiny external forces or anything that’s coupling into the atom to change say, its transition frequency. So the atom interferometry is used for lots of different applications on earth. It’s used for instance for very precise measurements locally of gravity. But my experiment is part of a bigger collaboration called the AION collaboration, which is a consortium of seven UK institutions. And we’re aiming to build an interferometer that can be used as a detector for dark matter and gravitational waves. So using the very, very precise sensing capabilities of the cold atom clouds to measure signals from, you know, astrophysical sources, which I think is such an exciting new application of those same cold atom techniques that are used to study the behavior of quantum materials. So it’s amazing how much those experiments have in common, despite such different goals. And there are a few other experiments across the world trying to do similar things as well.

We also spoke about the benefits of public engagement work, not just as something you can put on a CV, but in terms of the skills it can teach you that you can bring back into your research.

🟣Tiffany Harte : Definitely. Yes. I think there’ve been a few kind of tangible benefits actually that public engagement work has. So the first has just been very direct, is that I always feel so, so enthusiastic about coming to back to the lab and, and doing science after being able to go and talk to a group of people about how exciting the work is. I think it’s a really nice chance to stop and take a step back, away from the day to day. Some of the, you know, some of our work is tedious. We can never get away from that, but yeah, to be able to take a step back from that, see how exciting it is, see how exciting our goals are always makes me so enthusiastic to come back. But then, yeah, certainly in terms of field and communication skills, recognizing kind of how to, to pull out the important information - not just necessarily the information that you find the most interesting or the details that you’ve spent the longest working on - has certainly been useful feeding back into the collaboration.

Dr Harte also had some interesting reflections on diversity in UK science, and a warning that sexism is not a thing of the past, but something that everyone needs to be aware of and actively working to overcome, now and in the future.

🟣Tiffany Harte : Yeah, so I think that’s a really interesting question and in some ways quite difficult to answer because my career is somewhat limited. So I’ve been working in cold atoms full time for 10 years now, and that followed an absolutely amazing undergraduate experience. I’d say during my undergraduate years, I never really thought about sexism in science…possibly should have thought more about the broader aspects of diversity. But then as I went into full-time research, that’s probably when I - just from personal experience, so this is all anecdotal - maybe started to notice that this was something of a problem. So over those 10 years of, of PhD and then postdoctoral research, I would say in a sense, I feel that my experience is that some of those issues are becoming worse, but I do think that part of that could just be that as I’m increasing in seniority, maybe you’re just hitting more of those problems more often, or kind of approaching situations in which there can be more of a challenge.

I think maybe my expectations have changed. I think as a PhD student, I didn’t expect anyone to respect my expertise and I almost didn’t…it’s not that I didn’t mind, but I wasn’t surprised by being spoken down to or overlooked, whereas now, I’m not sure whether my tolerance for that has diminished or I have more of an expectation or realization that I do have, you know, valuable things to bring to the table, which of course is true of PhD students as well. And everyone should absolutely be treated with respect in their professional lives, as well as their personal lives. I should say most people that I’ve worked with, you know, haven’t experienced any problems. I think I’ve been incredibly lucky in comparison to a lot of people. But yes, just purely anecdotally, the trend that I have observed has not been a particularly positive one.

[53:12]

In Episode 9, we continued to focus on experimental quantum technology, and we spoke to Dr Viviana Villafañe of the Walter-Schottky Institute and the MCQST. Dr Villafañe works on quantum communications and on building the future quantum internet. Here’s what she had to say about her current work.

🟣Viviana Villafañe : So what I’m currently doing, I’m working on building a quantum communications network. So in this sense, my main goal is to achieve and build a scalable quantum technology that would allow us to do long range quantum secure communications. And the point is that some people might not be aware, but this quantum communications are already happening. For instance, there is right now a big network in South Korea and another in China, between Beijing and Shanghai where people are using quantum protocols to have secure communications. Nonetheless, even though these networks are secure because they are quantum, they have a challenge that needs to be addressed. And the point is that, up to date, there are no quantum repeaters. So this means that if you are, for instance, trying to distribute a single photon between the two people that want to establish a quantum communication you will have…and you are going to send this photon on for a fiber, you will have losses in the fiber. So typically every 20 of 50 kilometers, this single photo will be lost. And the message that you’re going to transmit will be lost. So what we want to do in our lab is to build a quantum repeaters, such that the information can be sent across long distances without the need of third parties opening and reclosing the message. And I’m hoping that we would, we can achieve this soon. And of course, by then the existence of these networks and all the trials that are happening, as I mentioned, for instance, in China and South Korea will be very beneficial.

🟣Viviana Villafañe: So the issue that you’re talking about, why is it so challenging to, to build a quantum repeater, is the same reason why quantum communications are essentially more secure than classical communications. So, there is in quantum physics a theorem that’s called the non-cloning theorem which says that basically, if you have an arbitrary message encoded in quantum information, this message cannot…essentially, it cannot be copied. So the same idea that we use for a classical repeater cannot be directly extrapolated to make it quantum repeater. And that’s the first reason why quantum communications are secure. And the second reason would be that for instance, if you have a spy that would like to read the message that you are sending, by the laws of quantum mechanics, it will - the spy, when he measures or tries to read, he will induce a state projection instantaneously.

So the transmitter and the receiver would be aware that there was a problem in the connection. So these two things make quantum communication safer. And these two things also are the ones that are saying that building a quantum repeater is a much more challenging task in this case. But, luckily there are a lot of proposals, theoretical proposals on how a quantum repeater should work. One is to just, if you hav, a very long distance, you can start by dividing the total distance between transmitter and receiver in several segments. And then between each segment, you could place our quantum repeater. So the idea would be that then what we need to do is emit single photons in each segment and use the quantum repeaters to entangle photons that arrive for neighbouring segments. And we could repeat this protocol until we extend entanglement between the photon that is in position of the transmitter and one is of the receiver. So this is what is called entanglement swapping. So it’s kind of a teleportation algorithm that it’s extended to build a quantum repeater.

When it came to advice, Dr Villafañe told us about the importance of trying to relax, enjoy what you do, and make sure to surround yourself with inspiring people.

🟣Viviana Villafañe : Uh, that’s a tough one. I would say it’s more like a collection of advices. First, it would be like, try to enjoy and relax a little bit. Enjoy every time you are going into the lab, just don’t be so self-conscious, take your time. Don’t rush through it. Take my time to pose my own questions, to explore, try to come up with my answers, try to set like stepping stones. Today, I’m trying to learn this or asking this question. I will set the basis and then I will continue because, yeah, this is how it works. You can’t rush through it. And the second would be like, for me, it’s really interesting…something that I’ve learned is that you need to be less strong network of connections. You need to…nobody does science alone, so we all benefit from discussions and teamwork.

So it’s good that you build a nice strong team. You are in a place where you feel comfortable and be able to discuss with all, yeah, your collaborators, the people around you. And yeah, for me, this is very important. Before it was very important as a student, like being in a place where you feel motivated and now it’s, it has become very important as a postdoc just to learn how to build a team, how to inspire people, how to show them the big picture. Yes, we’re aiming to do quantum communications in the future because the quantum internet is coming. Today, we have to fix the laser. Sorry, come with me. I will show you how so. Yeah, that’s the advice I would say.

[59:22]

In Episode 10, we again ventured outside of academic research and spoke to Dr Araceli Venegas-Gomez, founder of a unique company named QURECA that operates at the interface between academia and industry. But before getting to this point, Dr Venegas-Gomez had already had a very interesting and unconventional career:

🟣Araceli Venegas-Gomez : Sure, yeah. This probably could take the whole podcast, but I will try to be brief. So when I was working for Airbus an aerospace engineer, I was quite successful. I was getting, you know, this career path into management, everything was going well, but I guess that I always wanted to learn more about physics and science in general. So I decided to take a Masters in medical physics. Why? It was the only thing that I could find that I could do while I was working full time and where I could learn kind of a different field in science. And when I was doing this Masters in my free time, I came a little bit across Magnetic Resonance Imaging and quantum physics. And then I learned this Hilbert space that I never heard before and I wanted to learn about it.

So, in my free time after my full-time job and my Masters in medical physics, I wanted to learn quantum physics. So that was for really long time. And what happened is that I was taking holidays and free time out of my work to go to conferences and to learn more about quantum physics. So at one point, and I’m gonna give you the details now, I went to Mexico for a trip. And when I was coming back from this trip, I had some spare pesos to spend at the airport, and I bought a book, and I’m mentioning this because that book changed my life. And the book said, “Do what you want and the money will follow”. And it’s really a lot of stories about people that…they were quite successful in their careers - lawyers, teachers, whatever - but they wanted to do something else.

And that was really the point that I kind of sit down and ask myself, what do I want to do with my life? And I don’t know if it was the crisis of turning 30 or really that book, but the answer to that question for me was learning quantum physics. So yeah, I was a little bit a geek, I guess. And I said, “That’s my goal. I want to go a PhD in quantum physics”. So I started to apply. And to be honest, I got a lot of rejection because people were saying things like, “You are an engineer, you don’t know anything about mathematics”. Well, I can tell you a lot of stories of rejection, but thanks to networking and an online course that I got from some university in the US and connections, I ended up moving to Scotland where I got the opportunity. So this took years, to be honest. And I finally moved to Glasgow where I had a Masters of Research at the University of Strathclyde and then my PhD. So it was really the, I guess the passion about learning and the time to sit down and reflect what I wanted to do with my career.

Having heard about her career so far, and the wide range of very different skills learned along the way, we next wanted to know how this led to the founding of QURECA.

🟣Araceli Venegas-Gomez : Yes. So as I mentioned before, I had the feeling that I wanted to catch up. So I was just reading everything about quantum everywhere. And it was also the beginning of quantum technologies as an emerging field where I was seeing quantum as not any more just some academic field, something really research specific, but more industry and business. And I was seeing all these academics that they were starting to get involved into business, but they never did any business. They never worked in industry. So I started to feel that I was in a kind of a middle position or strategic position where I could understand people that were coming from industry trying to understand quantum, and people coming from academia who were trying to understand business. So what I did, every time that I was in an event, a conference or anything, I was asking people, “What do you think that is missing on this kind of emerging field?”

So I was just gathering information. I was starting to get really active into social media. So I was…pretty much any news that I was seeing on quantum technologies, I was discussing in Twitter. So I kind of started to get known in the field. So I created a big network. I went to the launch of quantum technologies, national initiatives in the UK, in Europe, in the US. So all those kind of activities came out, I was asking myself what can I do with all these, right? Because I was like, either I become an academic or I go back to industry. But then, I met very clever and amazing people who said, “Why don’t you create something new?” And I was like, I would love to do that. I was thinking maybe to join one of these national initiatives and programs, but to create something new, how could I do that?

I had no idea. So I got the advice to apply for a Fellowship. I did that and I won the Fellowship - that was from the Optical Society, the Milton and Rosalind Chang Pivoting Fellowship - it was really focused on people who wanted to change their careers and create something new, not really going into industry or creating something really research focused. It was something new. And I was the first one applying, and I got it. And thanks to that Fellowship I created QURECA and that’s how everything started. And really why I created QURECA, that is Quantum Resources and Careers, it was to answer all those questions and needs that I found that people were saying, “We need this and that”. And I said, I’m going to provide those resources in to the quantum community and careers because I thought that this emerging field needed people to understand how their skills have to be applied into quantum, how they could really find their dream job.

And also to work with companies on finding his talent. That’s how everything translated into what we do. That is different consulting activities like business development with quantum companies. We organize events. We do a lot of community building. For example, it’s about looking at the ecosystem and seeing where there are gaps. If you look at regions, there are some regions where there’s no much public funding. For example, in Latin America, we realized that there was a strong community of research in quantum, but it was not cohesive. So we launched Quantum Latino, and that was really successful. And we are gonna have the third edition next year in Mexico. It will be an hybrid event. So things about, again, seeing those gaps in the ecosystem, and really the focus is about skills and creating the workforce. And for that, we focus on education and recruitment. So as you see, we do a lot of different things. We work globally, and it’s really about having this strategic position in the middle of the ecosystem.

The unique nature of QURECA at the intersection between academia and industry also meant that Dr Venegas-Gomez had an interesting take on the question of diversity in quantum physics. 

🟣Araceli Venegas-Gomez : Very good question indeed. So if I go back when I was in aerospace engineering, my studies, I think in my field we were like 10% women. So for me it was kind of a normal being in the minority. And when I moved into industry, it was kind of a similar numbers. But for me, you have to imagine it was not just the fact that I was a woman. It was a…I was young, and coming from engineering, so on the technical side, I was in a country where I didn’t speak the language. So I kind of had all this against me. So I had the feeling that anything that I was doing, I had to demonstrate twice in comparison with a male, maybe the same age, and from the nation where I was working.

And answering your question now about recruitment, a lot of companies, they come to us and say, “We are looking for this profile. And if it’s from, you know, if it’s a woman, if it comes from a minority background, please, it’s much better because we want diversity”. It’s so hard. We know that there is a talent shortage in quantum already. So now imagine if it’s hard to find a person just that it can tick all the boxes, how hard could be a person from, you know, a minority group that can tick all the boxes? It’s just really, really hard. So I think diversity is in the front line of everyone at the moment in academia and in industry in quantum. It’s just, yeah, trying to find the needle in the hay stack that is already hard to find.

[68:20]

In Episode 11, we returned to academia and spoke with Dr Alba Cervera-Lierta, a Senior Researcher at the Barcelona Supercomputing Center (BSC-CNS) and coordinator of the Quantum Spain project. Now is an exciting time to be involved in quantum computing, so we asked her how she got started in this field, and what she is working on at the moment.

🟣Alba Cervera-Lierta : So, as I was saying, when I started working in quantum information and computation, there was, you know, very little use of this technology. So of course, there is a lot of theory done. There was a lot of experiments going on in labs, but there was not such you know, relationship between theory and experiments beyond, you know, particular collaborations. So when at the middle of my PhD, it was announced by IBM that a quantum computer was in the cloud, would be in the cloud, so everybody could then use it. And that changed completely the way that I was thinking about this field. And I think that it also happened with other people, and that make a big revolution in that sense, because that means that quantum computers made the jump from an experimental setup to something that can be operational, to something that people from other fields can use without needing to have access to a lab.

Right? So to me, this is just the beginning of what’s going on in this field. So this field was developed in the eighties, nineties. At the beginning of the 2000s, we start having the first big experiments, but still everything very experimental, very primordial in labs. And now it’s making a huge, huge step towards operation, to become operational, towards becoming and developing these infrastructures. Because now the technology is ready for this next level. So in that sense is the…precisely the field I’m working on. So, on one side, as a researcher, I’m working in near term quantum algorithms, which means everything that can be run in current term, quantum computers, which unfortunately is not all kind of algorithms, but there are many things that we can do and try. And on the other side, also helping to develop the infrastructure necessary to boost all this ecosystem.

So in the end I’m working in a supercomputing center and something that is happening in this HPC community, high performance computing community, is until very recently they were not investing in quantum computers because we already have the super computers. There are a lot of things to do with super computers, and they were working in this level of development, the level of offering all the infrastructure to the users to use the machine for different applications. And quantum computers were not there yet, but this is changing. So quantum computers now are ready for that, and that’s why it has perfect sense that these super computing centers start acquiring these quantum computers and opening them to the public, to the users in the same way as it’s happening with super computers. So in that sense, I’m coordinating a project that is trying to do this thing for the particular ecosystem of Spain, but also Europe, because very recently, two weeks before we are speaking right now, it was awarded the first six European quantum computers in Europe, and one of them will be in Spain together with this other super…quantum computer, sorry, from the quantum Spain project.

So we’ll have two quantum computers in our center. And this, as I was saying, this has perfect sense in a super computing center because we are the ones who acquire the technology and offer that to the users ,while universities and and other and also industry of course, develop the technology. And once it’s ready, they sell that to us.

As always, we also asked Dr Cervera-Lierta about diversity in science, and how people in leadership roles can make sure that everyone on their team feels valued, comfortable and safe.

🟣Alba Cervera-Lierta : So the, all this problems with the lack of diversity in, especially in physics in general, in computer science, also of course in quantum computing, much more. So as you go smaller and a smaller and it fulfills, it becomes more and more complicated. But the problem that I see is we need years to change that, and we need to start as soon as possible, of course, but it will take years to see the effect probably. So sometimes it’s hard to push some policies because you don’t see any direct effect, but you still need to continue with that anyway. And the problem that, for instance, I face is creating a team of people that work in quantum Spain, for instance…of course, I don’t decide everybody that works in quantum Spain, only the ones that that work here at BSC related with this project.

But anyway, there are no candidates that are from other diversity backgrounds. So there are very, very few of them, and it’s really hard to find them. But in some cases they exist, in some cases they don’t feel maybe safe in this environment. So I’m not sure about that. And that’s the, that’s the point that we need to understand. And as a woman in science, I can see…so I never have faced any, any problem, at least not obvious, not in an obvious manner by the fact that I’m a woman working in a field dominated by males. But I can see that sometimes it could be hard because I’m going to many meetings. I am the only woman there. And because I’m happy with my job and I’m, I mean, everybody’s very friendly and always treat me with a lot of respect.

🟣Alba Cervera-Lierta : Exactly. Sometimes it’s not only about the diversity itself of your team, but also just to show that this will be a safe space because if your team is apparently diverse, but then people are not comfortable, then it’s not diverse at all, of course. So that’s also very important.

[74:45]

In Episode 12, we crossed the Atlantic once again and spoke with Dr Stefanie Czischek, an Assistant Professor at the University of Ottawa. Dr Czischek works on applying machine learning techniques to many-body quantum systems. We asked her to give us a crash course in what neural networks 

🟣Stefanie Czischek : Yeah, so neural networks, I mean, we know that they appear in various different fields nowadays. We use them pretty much every day in our phones or in the cars or wherever. So the idea is…like, a very standard example of an application for artificial neural networks is the classification of an image. So the basic example is you give the neural network an image and it tells you whether there’s a cat or a dog or a rat or whatever in the image. So some kind of animal. This is also of course used for self-driving cars. So you want to know whether there’s like a speed sign in the image of a camera or something like this, and these classification tasks you can use in the field of quantum mechanics. So this is something we did recently where we used this to detect transition lines in an experimentally measured diagram - a phase diagram - to automatically tune a quantum dot experiment.

So this is one approach where networks can help to advance quantum mechanics. You can use them to automatically tune experimental setups and to reduce the amount of human interaction. Another approach is to use neural networks kind of as dreaming devices. So there are neural networks which are called generative neural networks, and you can train them to encode a probability distribution and then they can dream, meaning they can produce samples or data following this probability distribution. And this is where we use it to simulate many quantum many-body systems where we try to train our network to encode a probability distribution describing a quantum state, and then we can generate more measurement data from this classical neural network instead of running the quantum experiment.

It's important to note that this is not the same as the field of quantum machine learning, which tries to make use of quantum principles to improve machine learning algorithms.

🟣Stefanie Czischek : That’s correct, yeah. So yeah, this entire intersection of artificial intelligence and quantum mechanics can be approached from two sides. So either you can use artificial intelligence to advance quantum technologies, which is what I’m doing, or you can go the other way around and you can use quantum computers to advance artificial intelligence or artificial neural networks which yeah, is also a very interesting field and there are quite a lot of people working in this field, and it’s also very interesting. It’s just not my focus right now.

Dr Czischek also told us about some of her work on biologically inspired neural networks, which are designed to mimic nature rather than to run efficiently on a classical computer.

🟣Stefanie Czischek : Yeah, so this is definitely one of my favorite topics. So I like to work on this intersection of biologically inspired neural networks and quantum systems. And the motivation behind this is that if we look at our artificial neural networks that we all know pretty well now, then as the name suggests, initially they were inspired by the biological brain, but over the time they have evolved pretty far away from the brain and you can already see this by their setup. So you can imagine that your brain doesn’t have a leyered neuron set up, but it’s more like a fully connected or randomly connected network of neurons. And this development…I mean on the one hand it’s good because these neural networks have been developed with the motivation to optimize their performance on our conventional computers, and that’s why we can use them now. But at the same time, we are missing some of the benefits of the biological brain, which is on the one hand extremely small and also extremely energy efficient.

So if we compare our brain, which has about 86 billion neurons, with the supercomputers that our artificial neural networks are running on, then you can see that our brain is much smaller and consumes way less energy. It’s also extremely fast. So if you just see an image for a few microseconds, you can already recognize this image and you can interpret it. And this is much faster than our artificial neural networks. And so people are now trying to get this biological aspect back into these neural networks. So this brings us to these biologically inspired neural networks, which hopefully bring these benefits of speed. Yeah, small size and energy efficiency back to artificial neural network applications. And the reason why I’m interested in combining this with quantum physics is that I hope that from these biologically inspired algorithms, we can maybe get more insights into quantum mechanics so we can hopefully overcome the limitations of our conventional computers and artificial neural networks. And then at the same time, because these biologically inspired neural networks are so small and so energy efficient, we can hopefully integrate these networks in quantum experiments, which can, for example, be tuned with artificial neural networks. And so this energy efficient and small setup proposes to directly integrate these artificial or these network algorithms in the experimental setup, minimizing the interaction with the outside world and the amount of data transfer to classical computers.

And finally, we asked Dr Czischek about her experiences of how different countries can have different attitudes towards diversity in physics.

🟣Stefanie Czischek : Yes. So I mean, as a woman in physics, this has always been an important topic to me. Yeah, I’ve definitely experienced that. The field is still very male dominated. I also experienced that EDI - so equity, diversity and inclusion - is a much more important topic, or it’s just a more present topic here in Canada or North America in general than it is in Germany. So I definitely noticed over the last years that I was made more aware of this topic during the last years. But thinking about my career, I also find that in both countries, I rarely experienced moments where I felt treated unequally compared to men. So these moments still exist, but from my experience, they got pretty rare. And so I think the mindset has already changed a lot, and for most people…so based on my experiences, I would say the mindset is…it’s still a problem, and we still need to work on finding the right mindset to treat women and men equally in physics.

But I think this is not the main problem anymore. And the main problem, which I also now experience as a professor, is that the pool of applicants for a position is just not diverse enough. So if I want to build a diverse research group, then I also need a diverse pool of applicants to choose from. And if this diversity is not given, then yeah, it will always be a male dominated field if they are not enough women applying for positions. And I think this is the point where we need to get up and do some outreach, get outside, share our stories inspire young students and show them that they can definitely have a really nice career in academia and in physics, and just encourage them to follow their dreams and live their lives and consider a career in science.

At the time of recording, Dr Czischek is currently growing her team and on the lookout for graduate students, so if her work interests you and you’d like to get involved, please do check out her research group website for more information. 

[82:27]

And there we have it – a brief recap of all 12 episodes that made up Season 1 of insideQuantum. Thank you for sticking with us in this episode as we revisited all of the wonderful guests who gave up their time to speak with us over the last few months, and thank you again to all the guests and behind-the-scenes helpers who made it all happen. 

You might be wondering where we go from here. If you’ve enjoyed what we do, then I have good news – we’re currently planning Season 2, and have already invited our first few guests. We’ll also have at least one episode hosted by a new mystery host, who you’ll hopefully hear more from very soon. At the moment, we’re planning at least another 12 episodes, and then after that, who knows? By that point, my current postdoc contract will have ended and I don’t know what I’ll be doing, whether I’ll still be in physics, or even what country I’ll be working in, so whether this podcast continues beyond Season 2 will depend on how much people want us to continue it, and whether we can find the funding to do so. 

In the meantime, if you’ve made it this far, I’d really appreciate hearing from you about what you’ve liked about this podcast, what you didn’t like about it, what you think we could do better and what you’d like to see more of in the future. I end every episode by asking if you’d consider liking and sharing the podcast. If possible, I’d like to also ask you to leave a review on the podcast service you use, if they allow reviews, and if you’re listening to this on YouTube, please do drop into the comments and say hi. I’m not asking this out of vanity; the more engagement and interaction we have, the more listens and reviews we have, the more likely this podcast will be recommended to new listeners, and the more we’ll be able to continue to attract funding and amazing guests to share their stories.

So, with all that said and done, I hope you’ll join us again for Season 2, starting in mid-January 2023. Until then, this has been insideQuantum, I’ve been Dr Steven Thomson, and thank you very much for listening. Goodbye!