Hello, and welcome to the physics world stories podcast. I'm Andrew Glaston. And on physicsworld.com, you'll be able to find the quantum briefing. As we will do in this episode of the podcast, it explores some of the most amazing stories from the past, present, and future of quantum mechanics, including the link between quantum physics and the Cheshire cat and possibility that, and stay tuned for this, we might be able to influence the past.
That's all to come, but on the front cover of the physics world quantum briefing was a wonderful piece of art inspired by quantum mechanics that I wanted to know more about, and there's quite a story behind its creation. So here, to start today's podcast, is the person behind it. My name's Felicity Inkpen. I'm an artist. I used to be a scientist. Academia was not for me, and I think that's the experience of a lot of scientists.
I was heartbroken about it because I I love science, and I built my world around it. I built my life around it. But I guess I felt quite lucky in that I had always always had this, twin passion of the art. And I've been making art my entire life since I was a tiny little girl. So when I finally made the heartbreaking decision to leave academia, I just wanted to paint. And my plan was I'll just paint and see how far I can go. And that was a few years ago. And that was just over three
years ago. And I've been making a lot of science inspired art because it turns out when you leave academia, it doesn't mean you stop loving science. So the is everything you do science inspired? No. No. Not at all. You know, as an artist, you're trying to explore you know, when I, when I first quit science to, to do the art, I didn't know what kind of artist I wanted to be. There's very many different ways in which to be an artist. And I had a period of play, which I
highly recommend. Like people should just take a little bit of time out and play and figure out what makes them happy. Really enjoyed that. And I have been making, you know, various different works, but I kept on finding that I kept on coming back to the science. I had one piece. So the first painting that I painted after I quit, the lab was a painting called synesthesia counting by numbers. Would you like me to chat about that a little bit? And Yes, please. Yes.
So, I have number color synesthesia. What that means is I see all numbers as colors. I didn't know that other people didn't see numbers as colors. It was only a conversation with colleagues that led me to discover this when we were just talking about what happens in your head when you multiply two numbers together. And one person said, oh, I see, a square getting larger. And somebody else saw it said, I saw a line getting longer. And I was like, what are you talking
about? Don't you just see the colors? And they went, oh, you're the weird one in this conversation. So, when I sat down in my art studio to paint my first kind of painting of, like, I am a full time artist now, it was just a painting of numbers. So I painted the numbers, one to a 24
because that's 32 squared. And, you know, 32 is beautiful because it's green and it's pink and it's yellow and it's got a little bit of blue in it because it's two to the power of five as well as being four times eight and the digits three and two. And that painting definitely, set me on a particular trajectory because it was such an important conduit for conversations. And that was definitely something in terms of finding my place as a artist inspired by science, because I was I I realized this
is what art is for. I can have conversations because of this painting existing that I could never have before. And they might be kept conversations with somebody who wants into my studio. It might be conversations with a neuroscientist who specializes in synesthesia. All these different ways of generating questions through communicating something visually.
And that feels like what I'm supposed to be doing right now is taking the strangest ideas and all of the kind of benefit and the knowledge and the love that I have of of my career in science and creating it or channeling it into visual images that that communicate those strange ideas and allow people who wouldn't necessarily feel that science was something accessible to them to say, oh, I know exactly what
you mean. Because now I've seen that image, I can describe something that I experienced or something that I've thought or something that, I don't know, I've I've experimented with. So that painting was very, very key, and it's, you know, I loved painting. I loved being it didn't feel like it was mine. That's that's another really fun thing about being an artist. Sometimes you're painting something and you don't feel like, oh, I'm the creator. You feel like this painting already existed.
Just the lucky individual that it gets channeled through, who gets to be the one to create it and then talk about it later. And I definitely felt that about that particular painting. So I it's central because you've mentioned that, you know, strange ideas. And the reason we're talking is because you've done the the front cover of the quantum briefing for physics world, which we will get to. But I just wanna, you know, to pick apart a couple
of things there. Because you've when you had that initial conversation, then they were, you know, you're the strange one. It's a conversation. Presumably, through your art, you've met more people who have the same sort of experiences as you do. Absolutely. And I think, you know, one thing so I used to be a neuroscientist, and, found out about aphantasia, which is when people have a lack of a visual imagination.
And, I I think if there's a spectrum, I'm probably more on the other end of it as, like, a hypofantasia kind of person. I know that they were doing research at Exeter University about a sort of spectrum between aphantasia and hypofantasia. And that's an example of something where you realize through talk through creating images and through talking about your process of creating images that not everybody has the same internal, you know, way of of,
experiencing the world. The but we will take for granted our, perception. We will assume that everybody else has the exact same perception and that, you know, if you say imagine an apple, I see what I see, and I imagine that everybody else sees exactly the same thing that I see. And it's it's not the case at all.
All of which is to say, like, I think it's really important to create things, paintings, mock sculptures, performances, whatever, that allow us to realize that we don't all have the same experience and to ask each other questions and to grow in empathy because then you're like, oh, I didn't, I didn't know that, that you experienced this world in this different
way. And yeah. It's, oh my gosh. It's such a privilege because people will come to me and I'll talk about the synesthesia painting or other paintings, and they'll share things with me that they'll say, oh, I've I've never shared this with anybody, but this is how I, you know, I think in a monologue or I think in a dialogue or, I think in images that look like this. And it's only because that piece of art has existed that they have felt able to find the words.
And and, you know, like, part of the fun of being an artist is having license to be the weirdo in the room, which means that other people feel very liberated to share their weirdoness with you, which again is, like, is a total joy. Right? And, yeah, you you you can just lean into or, you know, what have you done this week whilst other people have been in the
office? Well, and this week I've been messing around with ink and thinking about the sizes of molecules and how that changes how ink moves across a piece of paper and how I can make that into a piece of art that I like. You said 32 is particular colors. Is it always those colors? Yeah. Yeah. Yeah. Yeah. So, I mean, everybody who has number color synesthesia
is gonna see something different. And it is funny because sometimes you come across other people with number color synesthesia, and they'll you get into arguments about, like, you know, I was saying, obviously, four is yellow. And they're like, what are you talking about? Four is green. So for me personally, prime numbers tend to be quite flat and quite earthy. And then a number that has lots of factors tends to be multicolored and very vibrant. So, 24 would be a very colorful number.
It's got all of the you know, the the colors of, it's got yellow and red and orange and green because it's it's three times eight, and it's four times six. So the factors of it create, the mixture of colors. Whereas the number 17 is quite a boring mauve. And, but that's, that's my personal, you know, that's
just for me. Yeah. But it is really interesting then thinking about how we conceptualize numbers because for me, it's always, being just like a joy to see the patterns and the way the numbers relate to one another. So, like, multiples of four are always going to have that bit of yellow. So they're always going to have that little callback to, don't forget there's a four in here somewhere.
And, you know, that's it's a very useful and and beautiful way of of seeing numbers and then thinking about mathematics. And it is a fun thing to explore. I did a a the the second synesthesia painting I did was a painting of prime numbers, and I didn't know what it was going to look like. I sort of you know, I I knew what the prime numbers up to a certain amount looked like roughly in my head. But, you know, you get into the larger
prime numbers. And and what came back is it was yeah, the colors of, like, the earth kept on coming up. And I was like, oh, that's interesting. They're all quite flat, but they're all quite earthy. So that was, yeah, a a joy to discover. It so it helps with the maths as well as sort of helping with the art. Absolutely. I was one of those nerdy kids in school that really loved maths. I couldn't get enough of maths. I wouldn't you know, I'm I'm definitely not
particularly mathematically talented. I have a great many friends who are much more mathematically talented than I would ever be, but, but I definitely had a a a great deal of love for maths. And I I struggle to understand why other people in my class at school didn't see how beautiful it was to that, you know, they seemed to struggle with it maybe
a bit more than I did. And then after realizing that not everybody else see sees colors, I was like, oh, well, maths would be really boring and really dull if it wasn't colorful. And I was like, oh, right. Okay. That is why, you know, not of all all of our experiences are the same. And, yeah, I wish I I I could exploit
the synesthesia a bit more. I possibly should go back to, back to some of my undergraduate notes and and see if I can kind of, you know, exploit it to to finally get my head around, certain types of, notation. Yeah. I mean, presumably, when you were learning maths as a as a young person, that that that's when the colors came. Presumably. You'd learn. I I can't remember them not having colors. So, and, you know, it is as you say, presumably, it's not something inherent.
It's a learned thing. Right? And I you know, thinking back to to neuroscience and about how our, our circuits of sensation kind of are established so early in life, but also how plastic our brains are, how adaptable to change, how we can, you know, grow new connections in everything that we're doing. It's you know, I I think probably other people could lean into choosing different colors for numbers and seeing if it changes their experience of mathematics.
And, also, certainly, there's plenty of people who have other abstract sensations connected, like, you know, people who can smell music or taste people's names and things like that. I mean, it's fascinating, but for me, the fascination comes from the realization that our brains have all adapted that we all take for granted. And it's whatever way you have learned something, it's magical. My one just happens to be able to allow me to print pretty pictures sometimes. That's lovely.
Just a very silly question because you just mentioned names. How often as an artist do people ask you whether ink pen is your real name? About once a week. I I mean, what's funnier for me is that, more than once, I don't know even know how many times now, friends that I have known for years through art have turned to me and said, what's your real name? And I said And then pointed a breaker to them like, you've known my real name the entire time.
Yeah. And it's I it's funny for me because, nobody else in my family is an artist, of any type. And for them, it's just a name, you know, a name that they're proud of, but it's only me that gets the, you know well, of course, you were born to be an artist, a name like that. I'm like, well, scientifically, that doesn't go very far because my other members of my family were not born to be artists at all. The numbers are colors. Do the colors translate back into numbers if you see?
No. It's a it's it's a sad answer. It's it it doesn't really go back the other way. The color is just the color. It's the number that has the concept and the patterns. It's, you know, the the a kinda a number like 256, for example, that is beautifully bright and vibrant and colorful because of the factors that make it. Mhmm. So it is the the patterns that are drawing all these colors together. Whereas a color kind of stands alone as
itself. I mean, I can I can look at something and be like, oh, well, that would be, I don't know, 3,403? I'm looking at my glasses case right now. But, you know, it's not like the color of my glasses case has that intrinsic feeling of a number. Mhmm. It's the the numbers and the the beautiful patterns and the elements and the factors that contribute to how that number relates to other numbers. It's colorful. So you were drawn to maths and physics, and that's where you
sort of studied first of all. Is it was was the weird world of quantum something that drew you? Oh, absolutely. And, I had wonderful quantum physics lecturers. So I studied my undergrad at, the University of Leeds, and they at that time, they had a I don't know if it's still there, but they had a really wonderful quantum computing, bit lab, whatever you call it. So it wasn't
just, like, learning about quantum. It was learning about quantum or people who are really passionate about it and who were at the the forefront of science and who were so engaging and able to really communicate it well. I went to study physics. Like, I think, like many physicists, I wanted to be an astrophysicist. I wanted to study nebula. That was my kind of thought going into it as a teenager. And after a year's worth of astrophysics modules, I was
like, you know what? Astrophysics, not for me, not my favorite. Not to say I didn't love it, and I still, you know, I still love the stars, of course. How could you not? But, I found the the type of physics I really enjoyed was thermodynamics and statistical mechanics and the physics of gloop and complex fluids and and jelly and colloids and things like that, and eventually biophysics, which then lent itself towards the transition into
neuroscience, which happened later. There was a kind of a period of about four years when I worked in different jobs before I eventually decided I I wanted to go back to science. But, yeah, the the I was glad to have a really well rounded, physics education as an undergrad. And quantum's amazing, obviously. How can you, like, how can you learn about quantum and not just be fundamentally changed as a person after after learning about it?
I remember this particular lecture where our first year physics lecturer brought us the whole way through a derivation and kept on checking and being like, we all agree with it. Right? And you got a 100 students all nodding being like, yeah, we're all following this. We're all following this. And then the kind of conclusion was, therefore, many universes.
And you kind of had a 100 people who've all been following this derivation, following the maps the whole way through, agreeing with it with every step, and then being like, yeah. I can't really argue with that. I I had a friend, a physicist friend visit just this weekend. And, this physicist friend that I studied with as an undergraduate doesn't work in physics anymore, works in data science. And she and I were talking about how you're never not a physicist.
Like, even though it was, you know, our undergraduate years, we still have that identity so kind of fundamentally in ourselves. And I think, you know, quantum has a a big role to play in that. Yeah. So you have, created the front cover of the quantum briefing for physics world. Perhaps we could look at that as a sort of example of your creative process. Maybe talk us
through what how that came to you. And Well, I was delighted to get the commission, and the commission was, can you paint a picture of quantum mechanics that's, beautiful and colorful and original and not something that we've seen before? So no cats in boxes or anything like that. And, obviously, that's slightly daunting. My process when it comes to art is often it goes back to experimentation and play. And, actually, I sort of see experimentation and play as kind of one and the same thing.
The, I will go into my studio and I'll see what art materials I have around, and I will just start messing about, messing about like a kid. And then sort of thinking what would happen if? What would happen if? So I'd already, started this series of works, which were just exploring how how different pigments move, which had all started when I was just washing my brush. I was washing my some ink off of my paintbrush in some water, and I was like,
oh, I like that. I like the way the ink moves in the water. And then that led to more and more elaborate setups, adding in bigger glasses, different inks, different pigments, different lighting setups, getting myself a UV torch, buying a big spaghetti jar because that I could fill the whole way up with water. So I was thinking about, right, how could you represent quantum mechanics? And I'm I'm sort of, you know, going back and thinking about everything
I'd loved about quantum mechanics. And and the a lot of it comes down to probability, the idea of many things being true at once and, being able to kind of prove that through interference. So I was thinking, how can I create, a plain full setup where I can see, different pigments, different inks interfering and coexisting in the same space? Maybe that will lead me to something that I feel starts to represent something to do with quantum mechanics.
And what I, this is another like weird thing about being an artist. It's very hard to throw anything away, very because you're always like, that might be useful. So I had a bunch of expired printer cartridges, which had been sitting on my table, in a little dish. And I thought, right, maybe I can do something with these. And then, I thought it'd be really good if I could see how the ink flows out of the printer cartridges.
But, I I first had tried it in my big spaghetti jar, and I thought, no. No. No. No. We need something shallow, wide and shallow. So I went off to the shop and bought myself a oven dish, came back, and I thought, how can I light this? It's really hard to light this. It'd be really good if I had a light box. I didn't have a light box, but what I did have was a seasonal affective disorder lamp, you know, one of these sort of flat lamps that kind of emits incredibly bright
LED lights. So went and got that, put it underneath the oven dish, and then put my put some water in the oven dish, and then put the printer cartridges in. And then I was like, right. I like how they're moving, or I like how the ink is is moving out of that. But I think we can adapt how the ink moves a bit more. So then it was it was a a couple of days of intense play. I mean, like, getting really focused and experimenting with, like, what happens if I
add a bit of salt? What happens if I make a really thin layer of water before I add main cartridges? What happens if I add this? Etcetera, etcetera, etcetera. So, eventually, two printer cartridges and a very thin layer of, like, 60% sugar, 40% water was the golden kind of, mixture. And then I basically, I just sit in my studio, and I I watch and I observe. And eventually, I'll go, oh, I like that. And take a quick photo or take a video if you're sort of trying to see the dynamics.
And then from that, basically, start playing with the images, start playing with paints because then it's you know, I'm not a photographer. I'm a painter. I've created I've captured an image of a moment that can never be created again of of this this diffusion of dyes that I feel is is able to communicate something about, about, yeah, probability, about, states existing in the same place. But for me as an artist, that's it's not enough to stop there. I need to then have that engagement
with it. So, yeah, once I have that that photograph, it's then how can I recreate this? And I love working with oil paints. Oh my gosh. Everybody should have a go playing with oil paints once you have, Unfortunately, you have to buy a bunch of, like, solvents and mediums and things like that, and they do take an absolute age to dry. But oil paints, oh, they're delicious. They're just so fun to paint with.
So then it's going about, right, can you manipulate these oil paints on your on your, panel, in such a way that you feel is is managing to capture this spontaneous moment that you've captured in this photograph? So in some ways, it feels like it feels like a bit of a ruse or a bit of a luck that that I've taken a a couple of days of pure play, and out of it have, an image which is on the cover of the quantum briefing. You know, it it's what a great job I have. Okay.
It's amazing. And what a wonderful job you have done on that, front cover. Yeah. So if people want to see that, of course, you'll have to find the quantum briefing links to them on physicsworld.com. I just want to, before I let you go and play some more, I'd I will have to kind of out myself with something of a fan because there is some of your work on the walls of my house. Yes. Which is an illustration rather than a painting. Absolutely.
Yes. Well, I think it's something you might do for other people as well. But it comes from from my love of, Philip Pullman's work. Oh, I really hope we will talk about this because I also love Philip Pullman's work. Amazing. So can you tell me a bit about what that is that you do for Oh, absolutely. So I should probably give a tiny bit of context, which is to say that when 2020 happened, when there was a lockdowns, I
really struggled. And, unfortunately, that's part of my reason for leaving academia was the struggle that I experienced during, the pandemic. I have a preexisting phobia of pandemics, which I don't recommend. So, that time was very, very tricky. And, although I was still fully employed in neuroscience, I found that art was an amazing solace for me that when I was creating, I could switch off the anxiety of my brain, in a way that I couldn't really achieve doing anything else.
So I I desperately needed a project to keep my brain engaged, and, I thought about Philip Pullman and his dark materials trilogy, which I loved since I first read Northern Lights when it would have been about, I don't know, 10 or 11. And I wanted I asked people if I could draw their demons. So in the in the trilogy of, His Dark Materials, every person, their soul has a physical manifestation, which takes the shape of an animal. And in this trilogy, it's called a demon.
And I started off drawing some for close friends and then, started asking other people, would you like yours drawn And what a joyful thing to do. Also, like, I don't know how, how relevant this is for this chat, but I I was I was hoping that you might bring up his dark materials, Andrew, because, the character of doctor Mary Malone. I was thinking about it, in preparation for this conversation and thinking how fundamental that character is for me. Like, that's a character that as
a child I really related to. So this is a character who she's a a quantum physicist who's gone into neuroscience and then goes off on this beautiful adventure to try and understand, how consciousness works. And I think it's so important to have examples of people like that in art or in literature or in creativity to inspire people to to to see to imagine themselves as different kinds of people.
Like, I don't think it's, you know, it's not that much of a coincidence that I ended up being a physicist who went into neuroscience after being so inspired by a character like that. You know? But, yes, I really enjoyed drawing doing illustrations of of different people's demons, their soul animals. You know what? I've never actually done my own. I think mine is a cormorant. But Okay. Yeah. I need to sit down and and draw my own demon at some point.
I I I don't wanna ask too many questions about that because that's gonna go really deep if we start analyzing our demons. That's not too much. But, the the Mary Malone thing is quite interesting. I mean, I absolutely love the character of Mary Malone and that, as you say, for for many reasons, including that transitional, career that she's having. Yes. You say you're
inspired by it. I'm sure there's some of that in there, but I think it's also that that's that character enabled you to see who you
were. Yes. And that's the importance of art is that sometimes you need to see something on a page in a book or in a performance or in a hear it in a song or see it in a painting before you're able to articulate, oh, this is how I feel about this thing, which, you know, going back to beginning our conversation is why the synesthesia painting has been so interesting because so many people have been able to articulate things that they'd never able to articulate before.
My, I did a a art exhibition back in 2016, which was all about, a phenomenon phenomenon called lapel de vid or a call of the void, which if you've ever been up in some high place and you've had a little intrusive thought of, like, what would happen if I lent too far over this railing? That's lapel David. And, so I created all these paintings, explored this idea and then presented them. And, oh my gosh. I had the best conversations with strangers because people would say, I know exactly what
you mean. It's like when I'm driving really fast on the motorway and I have a little voice in my head, that's like, well, what would happen if, or, there was some very,
interesting examples that other people gave me. Actually, maybe I won't share them because maybe that's a breaking of trust, but, it's a privilege as an artist that you get to be exploring these ideas, creating images, and then having the most amazing conversations with other people as those other people find value in the images that you've created. It's it's a complete privilege.
Yeah. I tell you what's really lovely about the demon illustration that you did for us is when people come and stay with us or come and visit us, and they look at the picture and then they go Uh-huh. Hang on a second. Yeah. Is this is this and you're like, oh, yeah. Now I've got a proper friend because they recognize what this is. I I I love that too. I love, so as I said, I think mine is a cormorant.
What is absolutely certain is that it's a bird because whenever I've sort of mentioned it, the concept of demons from historic materials to anyone, they've always gone, oh, you're a bird of some kind. Mhmm. And then it's just different people. Some people my I think my mother thinks I'm a jackdaw. Okay. They're very clever. I didn't know that's about me. They I think I think it means they're very clever, very useful. You use the tools to make the world a better place, so that seems fine.
I like that interpretation. If people want to know, more about your work, where would they find you? Thank you so much for asking. I'm on Instagram. I have a website. Basically, if you search for Felicity ink pen, it is an unusual name. You're gonna find me. So you can just chuck my name into your search engine of choice, and you'll be able to find me on those. I'm also on Blue Sky and Substack at felicity ink pen. I highly recommend that you do find your way to looking through
Felicity's work on those various links. But to dive deeper into the quantum briefing, here's someone whose voice and name might well be familiar to quite a few of you. Hi, Andrew. I'm Tishna Kumar Sarayat. I am the features editor for Physics World. And this year, my special project all year long is all our coverage for the international year of quantum technology and science twenty twenty five. So it's all quantum all the time for me. Yeah. Does that make you feel a bit weird?
I like that part. No. Do you know what? My my aim for this year is to make most people think that quantum is not that weird. Or if it's weird, it's a fun kind of weird and not, oh, no idea what's going on kind of weird. Okay. But does because I find when I'm doing these podcasts about quantum that it makes me it makes me kind of think about what's going on around me in a slightly different way. If you're doing it all the time, does it not do that a little bit?
It does. It does. It makes you have this amazing appreciation for how strange and wonderful, the world is around us and and the fact that there's still so much to be learned. There's so much that we don't understand about what is essentially a really fundamental aspect of our existence. So you have a quantum briefing. We we were we were developing this briefing in the early half of the year, and, you know, we were saying, well, we've
got so much excellent content in it. We want something really exciting on the cover. And here's the thing. Right? Quantum mechanics, very popular subject, very hard to have interesting pretty pictures of it because it's not something you can photograph. You know? It's not like astronomy. You can't stick a pretty picture of a galaxy or a nebula on. It's really hard to visualize.
And I realized that all the magazines and things that are out right now, everyone's using the same 40 or 50 pictures from, you know, Shutterstock and iStock and Science Photos. So it's either a picture of a so called quantum computer, which is mostly the dilution refrigeration part of it because the actual computer is really tiny and boring looking, or it's something, you know, some sort of bushy lines that look vaguely like an atom
or something like that. And I wanted something really different and visually exciting on the cover. And so I thought I wanted an artist who really understands quantum mechanics to represent, their idea of key quantum concepts on the cover. And so I thought of, Felicity, Fliss, who used to work at IOP publishing many years ago, and she has a big background in science. And so I sort of reached out to her and I said, hey. Would you like
to paint something about quantum? And she absolutely loved it, and so, you know, I'm sure you've heard her talk about how she came up with the the dyes and the imaging and then her stunning painting, cubit's duality, which I love, which I think is just amazing on the cover. I think it really gives you this amazing sense of the ideas of entanglement and superposition, but in a beautiful way that is quite rare to associate with quantum mechanics. So yeah.
It's quite a lovely thing, isn't it? Because I've done some things in the past where you've been kinda working on something, and then as a result of what you're working on, something else has come out of it. Some sort of art or creation or something's come out of it. It's just a lovely thing to happen, isn't it? Absolutely. And I'm so happy to say that this painting is being displayed all over The UK at different events.
So two weeks ago, it was displayed as part of the Great Exhibition Road Festival in London, and it was part of Imperial's, quantum art, quantum jungle where they had all these amazing, pieces of quantum art, some of them interactive. And there were so many people there, so many young children. It was amazing having them all look at this and go, oh, pretty, you know, which is quite rare for quantum. Hopefully, the painting is going to also be displayed at the, Royal
Society Summer Festival. And later on in the year, the Science Gallery in London is having a special quantum exhibition, and, Qubit's Duality will be seen there too. So if you're anywhere in The UK, keep your eyes peeled for our stunning quantum art. Amazing. Yeah. I've I didn't know that. That's a delightful thing. I'll be finding my way to one of those. Because the other place I can see is on the front cover of the Quantum Briefing, and I would like to just sort of open the pages
of that and look inside. What's sort of drawn you as you've been looking into it and, putting this this briefing together? You know, sometimes you you come up with what you want to go exactly, what you wanna cover in this kind of thing, in the special collection. And other times, you sort of look at we we have so much exciting quantum content that we pull together, this massive spreadsheet, and then we actually had to cut things down. Because if we we printed it all and put it all in,
it would have been 200 pages. It would have been a book. So we had to sort of choose the best of the best of the best, the most interesting things. And as we pulled, content together, we realized that naturally, all the content divided up into three sections that with a little bit of whimsy, we decided to call quantum history,
quantum mystery, and quantum industry. And then, of course, there's a bit of science and culture because we like science and culture, and we think that's a key part of, the scientific process. So that that's sort of the sections, that it covers. Obviously, history looks back at, some key people, who were pivotal in the discovery of quantum mechanics.
Quite a fun feature that starts out on the island of Helgoland, which is sort of where it all began a hundred years ago, the island on which Heisenberg sort of went to recover from his blistering hay fever and sort of wrote down the mathematical matrix equations of of quantum mechanics. What's really fun is that Helgoland was the site for, the hundred year anniversary conference, the Helgoland conference.
A week ago, and Nitin Drani, who is editor, of Physics World, editor in chief, He managed to go along to this conference, and, I would definitely recommend reading his blogs on sort of all the things that they discussed that look back at a hundred years of quantum mechanics and look forward at the next one hundred years. Is that was that a big argument in the physics world office as who was going to get to go to that one? Well, it's funny you say that, but do
you know what? This this island is really a tiny island off the coast of Germany. It's really not built for, you know, a huge amount of physicists to land up. And so very quickly, what happened with the Helgoland conference was that every possible location where you could stay on the island sold out. So they were asking people to pair up and share rooms. And the final option, which I heard a couple of people did succumb to, was to camp on the island.
And from Mateen's reporting, it was fairly cold and windy, so not exactly the dream, holiday or anything. But as Mazin says in his final blog, he felt that he could really understand why Helgoland was such a good place for thinking and coming up with amazing new ideas. So if you're if you're looking for a place for inspiration and some bracing sea air, perhaps Helgoland should be on your list now that all the quantum physicists have on hand.
I've I've I've got maybe I'll take get that painting somehow and take it with me. I'll tell you what. I'll just take the briefing. It's on the front cover of that. Oh, well, there you go. So There you go. Back at the history of it, if we can do that first of all, the other people in this story I asked that question knowing the answer to it. But other people in the history of the story whose story hasn't been told and maybe should have been? Yes. Absolutely.
You know, obviously, everyone everyone knows of Heisenberg. Everyone knows of of Niels Bohr. By the way, there's a great feature about Niels Bohr and something that he got really wrong, which I really enjoy. I really like it. Very clever people come up with what they think were fantastic ideas and then are very quickly proven wrong because it's always amazing to me how happy they are about that. They're always like, oh, well, try that, but this is more exciting that I'm wrong.
And so there's a great feature called when Bohr got it wrong. And I'll I'll leave you to read that to find out what exactly it was that he proposed in the very early days of quantum mechanics that was quickly proven wrong. But the person you referred to, the sort of missing person, was this amazing German physicist and philosopher by the name of Greta Hermann. Now she was someone who was a true contemporary of of Heisenberg and even John von Neumann. And so she was sort of very active
in those early days. And she because she was a philosopher and not just a physicist, she had some very certain interesting ideas about quantum fundamentals at a time when they were really discussing, you know, whether you you were in Boer's camp or or Einstein's camp, etcetera. And she sort of proposed some of the things that we later attribute completely to von Neumann was actually things that she had suggested or talked about or even
proved much earlier than he had. But, you know, because she was a very, highly trained mathematician. So she actually used her skills and training to point out some early flaws in von Neumann's early proofs that there were these no hidden variable theories, etcetera. And so she came up with some great responses to that, but no one you know, she sparred with von Neumann, but no one really knows about her today. After the the war, she sort of went off and did some quite different things because
she was interested. She was a free thinker. She was, you know, working with the unions and things like that. But she had these really great ideas about quantum causality, and things like that. And so her legacy is something that we really wanted to highlight in our history. Can I ask you a very silly question? Why is she not more well known? Why was the Oh, I mean, oh, Andrew.
I feel like I feel like, unfortunately, there is this you know, it's it's almost a term that we now know called hidden figures, and and you almost consistently, those figures are women or or people from other minority backgrounds who sort of played such key roles in so much of the fundamental development of science over eons, and they just got written out because they were the wrong kind of people to be in those stories and or they just didn't shout loud enough
or they just didn't have a platform for it. And, unfortunately, you know, it's sort of it's almost sort of happening again now while we haven't even got all of those hidden figures out and and women are being written out of the story again, unfortunately, in The US right now. But so, yeah, I mean, it's quite sad that we're still finding these amazing people. But, hopefully, all these stories will be told and appreciated. Yes. Absolutely.
I can't quite believe it's happening again. But, that's the history. Can we turn now to the mystery, not just the mystery of why the the people I've talked about more who were so instrumental in it, but the mystery of the science.
Absolutely. Yeah. So quite often, when we talk about quantum mechanics, people refer to things like quantum and, you know, entanglement, this idea that you you can have quantum particles that are inherently linked to one another even if they're nowhere in the same space and, you know, this can be across the universe, or or superposition where different quantum states are all at the same sort of happening at the same time.
And these are these quantum effects that are deemed so weird and strange, but, actually, there are a number those concepts have been around now for a hundred years, and they're pretty well understood. We test them in the lab. We do experiments with them. We use them all the time. But there's these other quantum effects that have maybe been discovered a bit later that are
even stranger. They're even weirder. And the way we see it is that they're so odd that they make superposition and entanglement seem almost ordinary. So that's what we kind of wanted to highlight through this, International Year of Quantum. And we've got the first three of these effects, in the guide. The first one is the quantum Zeno effect. Then we have quantum Cheshire cats, and then we have the quantum eraser delayed choice effect, which are all pretty mysterious.
Yeah. Yes. They are. But but to a certain extent, I wonder if some of these things do require a bit of time with reading in order to, you know, really grasp them Yes. Rather than just hearing about them on a podcast, I think. Yeah. I think these are what we kind of what we think of as lean forward articles. You have to pay a little bit of attention and stay with us to learn something truly mind boggling. Okay. So I'm gonna pick one of them.
And you could just shout at me if it's the wrong one to pick, but I'll just pick one of them. And I'm gonna pick this one, but largely because I was born in Cheshire. The Quantum Cheshire Cat. Absolutely. One of my favorites. And it also happens to me the same feature is also in the Jude issue of Physics World, and it's on the cover. So you have all these lovely cats on the cover. It's a very exciting cover.
Just a quick aside here because there are some wonderful illustrations, not only on the front cover of Physics World magazine, but in the quantum briefing to go alongside some of these wonderful stories of quantum physics. So I do recommend if you're interested in that kind of cross section between science and art we've been talking about to delve into both the magazine and the Quantum Briefing. Back to Tushnet. Quantum Cheshire cats. Truly, truly mind boggling stuff.
So for those of you who've read Alice in Wonderland, you'll be familiar with the Cheshire cat, that has does this amazing thing where it slowly disappears, leaving behind its grin. The grin is the last thing that disappears, and Alice sort of says that I've often seen a cat without a grin, but a grin without a cat, that is the most curious thing I ever saw in my life. And so I'm in in the eighties, there were a bunch of physicists who who perhaps thought very deeply about grinning cats.
And so they put forward this really crazy proposition in the early nineteen eighties. This was, Yakir Aronov, Sandu Provasku, and, colleagues. And they came up with this suggestion that they said that because of the way quantum properties are of of a certain particle. So if you look at a particle such as a photon, now photons, particles of light, they have polarization. We all know what polarization is. Right?
So they found that you could have a quantum particle, a photon's polarization in a completely different physical location from the actual particle itself. So like the Cheshire cat, the grin is separate from the cat, and so the photons' polarization is actually in a physically separate location from the photon itself. What? Yeah. I know. I know. And the crazy thing is that they came up with this almost like a sort of thought experiment in the early eighties.
This this it was an idea, a concept that they said that, you know, if if you make, a measurement on a quantum system, it collapses the system. You know, it's when you have a certain entanglement or a certain position. You make a measurement. You sort of poke the system, and it causes the system to change immediately because quantum systems don't like being watched. And so you, you know, then you find out it's like open the box and you find out the cat is dead or alive. I was Schrodinger. Right?
But there's this there's this amazing idea. So so that's what you call a very definitive measurement, but there's this phenomenal concept in quantum mechanics called weak measurements. So that's like not fully opening the box, not opening it all the way and letting all the, you know, light out to see if there's definitely a dead cat. But what if you did something like just a teeny tiny little peak, sort of look from the corner of your eye without really looking? So
that's what physicists called weak measurements. So that's where you do sort of a series of very gentle pokes on a system, and you keep measuring those. You you make these tiny, tiny, tiny measurements, and then you add up the sum of this measurement to get a sort of coherent answer by doing these tiny, tiny, gentle pokes. So this this concept of weak measurements was sort of a radical idea in quantum mechanics when
it happened. And so so they realized that if you set up you do a certain series of sort of what they call preselection criteria to set up a photon, and then you put it through a beam splitter, send it, you know, do do the standard sort of interferometry that we do with photons, you know, to check, then you get a system where the photon ends up in one arm of the beam splitter and the polarization is in the other arm. And then you can put the two bits back together and do some really crazy things.
Is this actually been tested then, is it? It has indeed, and we do these experiments all the time, which is just crazy. They've they've so from when it was proposed and it's been done in different systems even. That's the that's the amazing part. And now what people are actually studying and looking at is the interpretation. So what does this mean? What does it mean if you can do these weak measurements? What does it mean if you can separate
these these things? How does it impact things like, you know, the this concept of hidden variables? Is there some hidden information within these systems, or is there something you know, how does it all work? And what I really like, I'll say this. So this feature was written for us by, Julia Georgescu, who is one of my colleagues at the IOP in London. And she came up with this really sort of fun idea of, cats at a pachinko parlor in Japan. So I don't know if you ever heard of
pachinko. It's, you know, like a slot machine, a jackpot thing that they have. And the reason why pachinko works really well is that in pachinko, you have this preselection so that the balls that drop from the top are in a certain spaces, and there is a criteria that determines
how they will fall through the machine. So she has this idea of cats are in this pachinko machine, and as they go through, you know, you have the beam splitter and the the sort of the cat is on on one end and the the the chair that you sit on to play these slots has the grin. So the cat is on the machine and the grin is on the chair. And so it's an interesting way of
thinking of this very curious phenomenon. And and, you know, I mentioned photons, but same thing happens with any quantum particle, really. So with an electron, you can do the same thing with its charge. With a neutron, it's it's magnetic moment. And with an atom, it's the, inertial energy of the atom. So we've tested it across all these platforms. So, yeah, crazy stuff. I don't know if this is a silly question. Right? But it feels to me like we're sort of peeping
into this world. You know, you peep there's that kind of peep but we're peeping into this world. And is it is it possible that the reason why these things are happening is just purely because we're peeping into it and there are connections that would make total sense if you were in it, but because we're sort of peeping at it. I mean, that is that is a big question. That is this fundamental, you know, one of those that's that's also something else that's really interesting that hopefully,
we'll get some answers to words. They say now physics world live, that will be published by the time you listen to this podcast. This idea that there are these inherent quantum fundamental questions that a hundred years later, we really have no answers to. But what's interesting is that we now technologically advance so much. The fact that we can have entangled states between, an atom in the lab and an atom, up in space. Right? We've done it. We're seeing it. We're still not quite sure what's
how and what. So these interpretations of it is what physicists are still trying to figure out. But there's this really, we're in a great position where we can use the technology that we have today to probe these fundamental questions and try and figure out. So there is a big question about the act of measurement itself in quantum mechanics, the act of observation itself in quantum mechanics and the role that plays. And that's sort of what Bohr and Einstein were arguing about from
the start. And we still don't have a very definitive answer. We do all these experiments, but we still can't quite explain how and why. And that actually I won't go into it in too much detail because it is really mind boggling and I recommend you read the article. But it brings us quite nicely to the third effect in the feature in the in the briefing, which is the quantum eraser or the quantum eraser and the delayed choice experiment
as it is called. And that's this crazy thing of, you know, most of us when you're at university, you learn about the double slit experiments. If you have a single light source, you send a photon towards a double slit that is really quite tiny. Even though it's a single photon because light occasionally acts like a wave, it's sort of that single photon passes through both of the slits. And if you have a screen at the other side of it,
you see this amazing interference pattern. So the photon has interfered with itself. But the crazy thing is that if you have that very same setup, but now you put some kind of detector on each individual slit so you can measure which slit that atom goes through. The minute you measure, you record that information, the interference pattern disappears. The the the yeah. The light refuses to let you know what it's gone. It goes, no. No. If if you do that, I'm not doing it. I'm going through one or
the other. And so it just turns into that Those dark and light bands disappear. And this is something you do in the lab and it's it's crazy. It's like how does it know? So that that in itself is this the role of the observer, right, and and what this information that is how how crucial information is in quantum systems.
But then to make things really, really mind boggling, the point of the quantum eraser is that once again, if you sort of delay the choice so what if you don't measure at the slit which slit it goes through, but you somehow have something past the slit that measures the interference. And then it kind of tries and looks at what's coming from the left hand side slit versus the right hand slide. So and, again,
brings us to these weak measurements. So you look at it weekly and you add it up, then you get that interference pattern back up. So it's this idea of what if you delay the choice of measuring it. And what's truly mind boggling with that, the sort of why we're talking about, does it rewrite the past?
Because this very same concept of this so so John Wheeler, the very famous quantum physicist and and thinker, I would say, he said that so what if you take starlight from a star that's millions of light years away and you do this double slit experiment with it, but then you you measure which slit is going through? Are you are we saying that we can control the starlight and what it does? Are we making it change what it did in the past by measuring it in the present? That's just
crazy. So so that was his big question. He's like, what does that mean? And so I think what most scientists believe today is that it isn't really this there is it isn't that you're actually having a path and influence in the past or that you are rewriting the past.
It's just that there is this truly quantum inherently quantum effect or quantum correlation that happens because of entanglement that we still don't understand, but we just have to appreciate that it is not something that we can put as simply in classical terms as rewriting the past. And, again, that even that, there there's experiments on this that people are doing and trying to make more sense of this link between information, observers, and quantum competing even. So it's not all
just very esoteric thinking. It starts out that way, but it always has quite practical implications. Yeah. That's an interesting thing, isn't it? Because I really recommend people do lean into that and and read fully the article and really, you know, get into it because Mhmm. I don't know about you, but I find myself looking at the news and the newspapers and things, and I just I just find the world a very odd place at the moment.
And it's much more fun to look into something like this with my spare time than it is to look into to the news. But is there a kind of, application of this stuff? The applications of this in society, what what other possible apart from just making me happier Yes. When
I go to bed. Absolutely. So like I said, there there are hopefully I mean, from what scientists and governments across the world are hoping is that the sort of quantum renaissance will have such a deep impact on our lives, in the long term because, really, what you can do with quantum computing, quantum sensors, and other quantum technologies, is is hopefully going to be wide ranging and and truly amazing once we achieve it.
We could talk a bit about quantum computing, but perhaps that's still something that's in the making. We don't have a definitive quantum computer, and that can do something really useful as of now that we can't do with classical computing. Our sort of massive you know, the bigger supercomputers that we have still outperform what the best quantum computer can do today. But that doesn't mean we shouldn't
be building towards it. And that's something that we're gonna hopefully dig into in a big way in our second volume of the quantum briefing that's gonna come later in the year. That's a little teaser for you. But one of the things that I love to talk about is the area of quantum sensors. So we talked a little bit about how, you know, quantum systems, you set it up and then you measure it and it quickly sort of collapses. You have this decoherence.
So they're extremely sensitive to the environment. And someone ages ago thought, wait a minute. They're really, really sensitive to everything going on around them. That could be a feature. It's something that we've been taking as a as a pain in the ass for all our experiments. But actually, it's gonna be something that could be quite useful. What if I try and use these very sensitive things as a sensor?
And so that scenario of physics that, you know, quantum sensors are way ahead in terms of they're being used in real life already. They're out of the labs and and and being tested in many spaces. And, Catherine Skipper, who was features editor, with us for last year, she's written this brilliant feature in the guide about quantum based gravity sensors. And that's really interesting because really often, we need to look at things,
that are buried under ground. And this is really important for construction or anyone who's doing anything that is underground and that's, you know, under a road, in a residential area, under a mountain, under the sea. There's many options of that. And we can use, cold atom interferometry, which is this idea of falling atoms to to test what's going on under the ground. And you might say, well, there's plenty of ways
to test that. You know, you have radar and this and that, and we have so many things. But the thing is whether whether you're doing something for the government or you're a construction firm trying to figure out what's going on on a road. Measurements for these kind of things can take weeks and months sometimes. They take really long. They're not as accurate as you like them. And, you know, the last thing you want is a road closed for a month because they're just trying to
figure out where the water mains are. Or worse, they've got it wrong and there's a hole in your water pipe, and now your road's closed and you have no water. So that's some of the stuff that some of these quantum sensors are looking at, these gravity based quantum sensors. The University of Birmingham has a huge, team, a collaboration working on many different aspects of this kind of stuff, with quantum gravimeters. I think it's some really fascinating stuff.
They've they've been testing it in exciting places like an underground cavern in the Peak District and out at sea in the in out at sea in the North Sea, with the navy. They've been testing, and that's all part of The UK's quantum technology hub for sensors and timing. So it's some amazing stuff that's already out there. The the quantum is already being used in the real world.
It's lovely, lovely stuff. I think, we should probably allow people to stop listening to this podcast and start reading the quantum briefing. How do they do that if they would like to find it? So it's the quantum briefing is free to read and access to everyone online on physicsworld.com. If you just click through to our magazines tab and you look at all of the magazines lined up for this year, you will see you you can read it online in a
nice flip book. You can download it in a PDF, all the options, and it's free to read and access. And it also includes little bits of audio and podcasts and so you can hear people talking about it. You can find out what author Ursula Caleb Gwynn had to do with Schrodinger's cat. Amazing. You can look at that beautiful quantum artwork.
You can look at an absolutely fascinating little bit of science fiction on on what happened if, Heisenberg never made it to Helgoland and what happens when he did a little a little sort of, parallel situation. And finally, you can also go and test your quantum acumen with our quantum quiz on the back page for a little bit of fun. And there are no prizes for that apart from feeling extremely clever. I'd like to thank Felicity and Tushna for talking to me for this episode of the
Physics World Stories podcast. And don't forget that you can delve much deeper into the world of quantum physics on the Physics World's website, physicsworld.com, where you will, of course, also find those blogs from Mateen Jurani from Helgoland. We'll be back next month with something else from this wonderful world of physics, and thank you very much for listening.