(inspiring music) - Hello and welcome to Conversations at the Perimeter. Today, we're so excited to share with you this conversation with Gunpathy Baskaran. He's based out of the Institute of Mathematical Sciences and the Indian Institute of Technology in Chennai, India and we're so lucky that he visits Perimeter Institute regularly as a distinguished visiting research chair. - Baskaran is one of the most interesting people I think I've ever talked to.
He's not only a fascinating scientist who's research delves into condensed matter physics and superconductivity and even the concepts of quantum biology, but he's just sort of a master storyteller whose enthusiasm and passion for science is really infectious.
- I think it's rare to meet a physicist who's such a great storyteller, and I loved hearing stories about the role that collaboration has played throughout his career and also about why he loves having discussions with students to inspire his research. - And what really comes across too is the gratitude that he has for the people that have helped him along his journey and now he's trying to pay that forward.
He's very passionate about supporting opportunities for young scientists in the developing world, and he speaks quite passionately about those opportunities and what they mean for young researchers trying to pursue big questions. - So without further ado, let's step inside the perimeter with Baskaran. So, hi Baskaran. Thank you so much for sitting down with us today. - So thank you Lauren and thank you Colin for inviting me. It's a pleasure to be here.
- So you have a unique position here at Perimeter. You're a distinguished visiting research chair. And so that means you're not here all of the time, but I know you visit here very frequently and I think your current visit is ending tomorrow. So I wanted to start out by asking you if you could tell us a little bit about this visit and some of the highlights. - I was missing Perimeter Institute for the last three years so I was making a personal visit to Los Angeles.
I thought I'll visit my daughter there for a month. Then because of COVID, we stayed happily for four months. Then I heard the news that Perimeter is opening. So immediately I wrote Perimeter and I'm here. And I'm very honored to be associated with Perimeter for nearly a dozen years. It's a great place. I tell wherever I go. It's a great example to be emulated, from the way it's funded and the way theoretical sciences are practiced.
So it's really an open ended respect for science as something that helps humanity. So yeah, respect is shown in real terms here. So I like this place and I have been coming very regularly. In terms of my research activities, it really helped me a lot because I meet a lot of people, meet a lot of young people. - Can you explain that a bit, why meeting people face to face and traveling essentially halfway around the world to do so is important to your work? You mentioned young people in specific.
Why young people? - Theoretical physics by definition involves lots of imagination and young people have definitely a lot of imagination. I'm reminded of one quotation from Picasso. He started as a realistic painter. Then he got bored with it, he started painting abstract pictures. Apparently, one of his aims was that he wants to be as imaginative as children and he could never beat them. In his mind, he wanted to mimic them and copy them, but he could never beat their imagination.
So in the same way, when you meet young people here, they have wild ideas, it's nice to talk about it. Many of them these days are extremely mathematical because mathematics is very enticing. Physics is an experimental science. Mathematics and physics experiments go hand in hand. When you meet young people, there are people who are motivated by experiments, there are people who are motivated by theories and mathematics. So it's fun to see. The variety is mind boggling.
I always compare it to the wild flowers I see when I go out in the spring. There's nothing like, you know, the most beautiful flower. Every flower is beautiful. It's very difficult to say that this is good, this is bad. As long as there is a pursuit in a sincere fashion, things will grow and that's what is happening. - You said theoretical physics requires a lot of imagination, youthful imagination, but it also requires a lot of rigor and mathematics and experience.
Is there a push and pull there between your experience and their youthful imagination? - When you said rigor, in fact, recently I was doing a conference, I was making a comment about meaning of rigor. There is conceptual rigor, physical rigor, and mathematical rigor. My colleagues, some of them are very rigorous in mathematics, they will make very sharp statements. There are people who will make very conceptually rigorous statements, mathematically may be very loose. So physics has all of them.
Turns out, if you look at the development of physics, conceptual rigor plays very important role and mathematical rigor or using appropriate mathematics has been extremely important. One good example is Maxwell's equations. We had Faraday's law, Ampere's law, Biot-Savart's law and then Gauss's law. And Maxwell had the genius to put them together in the then new calculus into one form, it became Maxwell's equation and changed the world.
So mathematical rigor in the sense of using appropriate mathematics is very important in physics. In terms of calculus, it was available to Einstein, he used it. Hilbert space was available, people like (indistinct) and Heisenberg, they used it. So using the right mathematics in the right place is something very important.
So it did not be rigorous in the sense of my mathematical physics friends call it as rigorous, or like existence, showing that something exists and is unique, that's the next level. What often worries, this is not the, they exists in their imagination, it exists in their mind, they want to bring it out. Very often, you know intuitively what is going to be the result, so you strive towards it, you are guided by mathematics towards it and this very often happens.
- In preparation for our conversation, you sent us a few articles that you had written. And one thing that stood out to me right away is that there were not many mathematical equations in those papers. So this was actually something I already wanted to ask you about is if maybe this is something that you tend to prefer or you find yourself more drawn to a conceptual, rigorous way of thinking? - Yeah, because as I said, there are many ways of looking at the structures in science.
For example, one of my papers where I said that all condensed matter phenomena mirror in biology in some way or other, simply because biology had three billion years of time to think through and work through, evolve and so on. So we are struggling for the last 500 years in modern scientific methods, so you have discovered many things, but biology has found it. So I do not know what mathematics will help me to think about it.
To me, there are many conceptual issues which are very important, but of course, without mathematics, they will stay there. You have to put it in the form of mathematics, elementary, simple models and if possible, new mathematics. That will take a long way. This combination of mathematics and conceptualization is something very fundamental in theoretical physics. I do not know if it is called rigorous, but the conceptualization and using right mathematics, maybe inventing new mathematics.
- That idea that you said everything in condensed matter physics has a mirror in biology, I had never thought of it that way until you sent us this paper. And then thankfully for me, that wasn't full of math and I was able to follow along. And it really hadn't occurred to me that, yeah, evolution has had billions of years of a head start on our physics.
And it almost feels like even though we're doing incredibly intricate and complex physics, we're still playing catch up to what nature has built already. How did you go down that line of thought? How did that first enter your? - Oh it goes to my teachers. I was fortunate enough to become a student at Indian Institute of Science at Bangalore. I had a wonderful mentor and teacher, Narendra Kumar. He was not my official guide.
He started as an electrical engineer and he ended up as a maintenance engineer in a national chemical laboratory. Then there was a theoretical physics was doing theoretical. We joined him and wrote a very quick PHD in theoretical physics, then he started working on cosmology and biology. So he essentially showed us that science is one. There is a web of science, every science is connected with everything else. So he was a source of inspiration for us.
So we had this inhibition competition into biology and math and so I was removed by my teachers. The five years that during my PhD days, I was like a playboy, you know, in the sense of never focused on my research, but seriously took other things, other courses and enjoying it all the way because I had a good fellowship. - So you were earning a PhD in one subject and learning about all the others at the same? - All the other things except for- - Except for what you were supposed be doing?
- To the extent my PhD paper, he's a great man, he's 95 now, he's still in Bangalore. So he was worried, he let me loose, he gave me full independence, but he thought at some point I should write my thesis. So at the end of three years he asked me, "Why don't you write your thesis?" I said, "I'm not satisfied." So he waited for six more months, asked the same question. Then after one year, that means at the end of four years. I said, "Professor, I'm not satisfied, I want to do some more work."
Then, apparently he thought in his mind, this fellow is gone case, he will never get a PhD. - He'd given up on you? - No, he didn't do, he couldn't do anything because he was a kind man, so I was doing enjoying physics. Then, you know, I do not know if I can say this, in India, marriages are fixed, are arranged, so marriage was arranged. So then I thought that before I submit myself to some lady, I should submit my thesis.
So literally in three months I wrote my thesis in preparation to get married. - I've never heard, no one has ever told us I got my PhD so I could get married. You're the first one to mention that. - No, it's that way because I thought if I get married, then there'll be other competitions, I will have no time to finish my PhD. And my guide was very good. He grabbed this opportunity and corrected my entire thesis in three days and gave it back to me so that I can type the manuscript.
So he was waiting for an opportunity. So I had good people in all along. - When we first sat down to chat with you, we got speaking right away and the conversation was flowing and we got talking about biology and quantum biology and I said to you, "Is this your specialty, your line of research?" And you said, "Oh no, no, that's not my bread and butter. That's something else I do."
And it amazed me that your sort of professional focus has been largely condensed matter and- - Strongly correlated electron system. - Yeah, super conductivity questions, but your interests are so broad. And so we continued carrying on about this subject of quantum biology. Has it been that way your whole life, even prior to the PhD, where you're just interested in a wide range of subjects? - No, it's very interesting question.
Prior to PhD, I was in a good college in Madurai, where I had a masters, very good teachers. So I took the subject seriously and I learned whatever I was learning. I had no particular fascination about quantum mechanics or mathematical physics. So I had no vision what to do. In fact, it's after coming to Bangalore, my ideas got sharpened. In fact, that's also an accident coming to Bangalore. I was about to finish my first year so I had no idea what I will do.
So one day my professor, Richard Pieris, he's a great man, it was a missionary college, Madurai American College. Missionaries used to invite like scientists to spend one year around sabbatical. So Richard Pieris was a scientist at Bell Laboratories, came to Chennai and Madurai for one year to teach physics. Then he fell in love with Madurai and stayed there for 35 years. So that was Richard Pieris.
He started postgraduate department of physics at Madurai and then he was my professor, very inspiring professor. So one day he asked me, "What are your plans?" Honestly I had no plans. So I told him, "I may become a tutor in a college." It's like a junior lecturer. "Suppose you don't get it, what will you do?" I said, "I may become a research scholar in Madurai University because I saw an advertisement they say about some fellowship so I may go for that."
"Suppose you don't get it, what will you do?" I had no idea. And he asked me, "Do you know about Indian Institute of Science at Bangalore? Have you heard about it?" I said, "No." "So you have some motivation, you have some energy, so why don't you apply for a PhD program?" So that's how I ended up in Indian Institute of Science Bangalore. The time took me, I never planned for anything in my whole life. I'm carried by time. I was not thinking about job at all, I was enjoying whatever I was doing.
Physics department won't invite me for an interview 'cause they had a way of screening. My marks at junior college level was not satisfactory so I was screened out on that basis. Then mathematics department selected me. They didn't have too many applications so I got in. The head department pass away, so the director of the institute, Satish Dhawan. So he was sitting in the entry committee and I answered questions so I was selected.
After four months, I was fascinated by a course on quantum body theory given by Professor N. Kumar whom I was mentioning. So I was so fascinated by it, I wanted to change to physics department if possible. So I directly went to the head of department who was the director. So he called the department, "Baskaran is interested in shifting, will you?" He said, "No, no, we won't call him because he was not even called for interview. We have different standards."
So he said, "As a director, I'm requesting you, please have a second interview for him." So they had a second interview for me and then I was selected. And that meant that Satish Dhawan, he's the father of Indian Space Mission. He was a very effective man, very selfless. He became the chairman of Indian Space Research Organization. And in India, among the various ministries, organizations, space research is one of the best. It's because of Satish Dhawan.
- You know, I love this story that you know, some departments maybe overlooked you at first just because of marks. and I think that we tend to look at marks as the first thing when selecting students, but I'm not sure that it's really the best metric. So what do you think we really should be looking for instead? - Yeah, that's a very good question. So as much as possible, one should interact with students. In our own institute, we often don't give too much importance to marks.
We are very liberated in terms of getting students for interview. There will be students with very low marks, but you can see their talents very clearly. Of course, you know it's very difficult to, when you have a big organization, there are rules and so on, it's very difficult to overcome this. But as much as possible, one should talk to people.
In fact, I know of some universities in India where they do this, they invite students and then they have about 50 students in a group and they go with the professors, they spend half a day together. That makes a difference other than looking at the application and marks and so on. One pyramid and scholars international, I know that they don't depend on mark, they depend on recommendation letters, which is another very important thing.
- And if you were 18, 19 years old now, would you follow a similar path as you've taken before or do you have advice for people who are just starting out? - I tell them that just follow your passion because these days, you can excel in anything. The world is different from my days. There are people who I want to become only a doctor, nothing else. But then on the other hand, you don't know your own talents. Your own talents may be in painting, you are fascinated, so give it a chance.
- It seems that you've benefited in your life from mentors and teachers who gave you that kind of encouragement, who gave you the leeway to explore. - Exactly, I should, very important to mention two teachers. When I was studying my 10th standard, I was regularly failing in my mathematics exam and I used to be a good student, I was not a naughty student, there were 52 students in the class, 52, 55, so it was a big class. So I was always sitting in the front and very attentive.
He said that, "You seem to be attentive, why are you failing at math?" "Sir, I understand whatever you are saying. I revised the subject one day before the exam. I go and sit in the exam hall, I'm not able to answer any question." He said, "Do you do homework and work out problems?" I said, "No sir, I help my mother." He said, "You should work out mathematical problems. Mathematics comes only by working out."
So he taught me how to do homework and work on problems because we had nothing like a homework, there is no compulsion. So he taught me how to record the problems. So from that period onwards, I started getting better marks, past mark. - He taught you how to reason through the problems, how to figure them out yourself or was it that you were not understanding how he was teaching them or you weren't
ingesting it? - No, no, no, I was understanding but I simply had no time to do my homework 'cause once I go home I started playing 'cause I am from hardworking parents, nine children and I had many, many friends. We used to play and there was a public park nearby, there's a gym, I used to be a street gymnast kind of thing, you know, do all kinds of things there. My parents were happy as long as I am not naughty and I'm not rowdy. So there was no insistence on sitting at home and studying.
Like in my one family, when I completed eighth grade, that's an interesting point, in which if you are studying, you can study. Otherwise, you go for a job. So many of my relatives came and wanted to take me away for, to become their apprentice in a shop. And my mom and dad, they were very enlightened. My dad was a very hard worker and he has not studied, he has studied until second grade. He was a socialist, you know, he believed in socialism and money should be spent for everybody.
Also, he realized the importance of education. So he said, since I'm studying without failing my annual exam, he said, "Let him continue." My mom also, she had completed eighth grade, which is a big step in her days. She said, "This boy should continue." So none of my brothers went beyond high school. And the thanks to great politician by the name Kamaraj, he had just introduced free education for poor children. Otherwise, it would have been impossible for them to pay my fees.
- So your education was government? - Government, exactly until my, nominal, half a dollar or even much less in Indian, two Rupees That's why I was able to study and I was not a problematic child. I was good at hands, I can make things, break it. So I wanted to become an engineer. But when I finished my school and enter college, you need some mark, some minimum mark. I did not have a minimum mark so I could not become an engineer. My friend said take chemistry or zoology or this and that.
I had no clear idea. Then one day I was going to the principal's office with the application form in which I had left the group without mentioning what it is. So my friend came out of principal's office. I asked him, "Christian, what subject are you taking?" He said, "Physics." I put physics. That was my how I entered into physics. - That's pretty amazing from a family where most people don't go past eighth grade to you eventually earning a PhD and then working as a physicist your whole life.
It's a different path that I assume most of your friends- - Oh yeah, yeah, totally different path, and at every stage I can say somebody lifted me up and put me up, that's something. Then, as I tell, in 10th standard, my maths teacher, and 11th standard, my English teacher. I was also failing in English. My English teacher, Reverend Father, KSR Antham he was a great man, but he was a terror to the students, he was very strict guy.
One day, he was reading the marks and I got 32 marks in English. 35 is the pass mark out of hundred. So he asked me, "Why are you failing?" I said, "Father, I can't memorize things." He said, "No, no, you should not memorize, you should understand." So he told me how to understand. He asked me to buy a dictionary and draw line under a word that you don't understand and then write the meaning in Tamil.
Then he said, "Read each lesson 10 times slowly and something will sink into your mind and go and write whatever comes out of your mind, you'll pass." And then I started passing the exam. So that was a very important step for me. - And then at some point I guess you had to even further specialize into strongly correlated electron systems. How did that choice happen?
- My professor, N. Kumar, he used to go to ICTP, International Center for Theoretical Physics, every time he'll come back and tell what is exciting. So he gave a set of lectures on strongly correlated electron system and modern developments in the field. - Just to stop, ICTP, that's in Trieste, Italy, that's the International Center for Theoretical Physics? - My professor was a regular visitor there.
He was an young professor and then he also started working on some, we had an outstanding visitor from Bell Labs by name Jay Ramen and he gave some series of lectures on some outstanding phenomena and strongly correlated system and heavy fermions. So I was exposed to that. That was not part of my PhD thesis. And it became very clear, strongly correlated electron systems are very, offer many challenges. Again, I have to tell, it's very important. I was fortunate to meet professor at Bangalore
by name S.K. Rangarajan. He was a phenomena himself. He was only an undergraduate, he became a senior professor, he had no PhD, because of his talent. So he found us students with Department of Theoretical Physics. So he collected us one day. "You are all very motivated and so on, but the way that you are doing theoretical physics is not correct. So you should have group discussion.
So he just collected us together and put us together and he would invite us to his house, which is not far from the institute, so we'll go at eight o'clock and sit for two, three hours. And he said the idea is not to read papers. He made it very clear. The idea is to go deep into classic papers. And one of the classic papers was by Philip W. Anderson, the great Nobel Laureate So I was introduced to Anderson's paper in Rangarajan's house through discussion.
So that's how I was exposed to this quantum many-body systems and so on. P.W. Anderson became my hero. It was very clear he's outstanding the way that he was doing things and so on. So it's in that background I grew up and wrote a thesis. - And he eventually became not just your hero but your longtime collaborator, is that right? - Yeah, that was thanks to ICTP. So I submitted my thesis.
The Institute of Mathematical Sciences wanted to give me a job, but they could not because I had no publications. So they gave me a nice fellowship. I got married already. So then I saw this advertisement by Winter College at ICTP so I applied for it. A friend of mine helped me to get travel fellowship and I went there. So there, it was again in a place, an eclectic place, I listened to all talks. My mentors there liked it because many people came down there to just write papers.
I never wrote any papers. I was interacting with people, so they were very happy with me, they made me an associate and so on. So I was going there every year since '76 for three months participating actively. And in fact they were so nice, in the second year they asked me to be responsible for a conference. They asked me to collect the best people in that field and organize a conference, which I did, and it allowed me to interact, I met many great people.
- You mentioned that a friend arranged a travel fellowship. Would you have been able to go, had that travel reimbursement not been possible? - No, it would not have been possible because it's a huge amount in Indian's salary and my background. See this friend's name is Subbiah Arunachalam. He's a champion of open access. He's 80 plus, he's still very active in India. So this guy and me met, we were together at Indian Science Bangalore. He was four years senior to me, four or five years.
But still, he came for a PhD much later so we were friends. So I wrote to to him saying that I am applying for a travel fellowship and you know there are bureaucracy and there are ways there may be delay and so on. He immediately took my application and went around the offices in Delhi and said that this boy should be supported 'cause he is very serious. So that's how I got my travel fellowship. Arunachalam is that. He's a kind of angel, you know, he helps everybody.
Whenever he gets a chance, he'll get people. He's a very selfless person. - So I think what we're talking about right now relates a little bit to the talk that you gave here at Perimeter Institute on Friday. Could you tell us a little bit about the subject of this talk you gave? - It was Abdus Salam and the International Center for Theoretical Physics, Abdus Salam at ICTP. Abdus Salam, as many of you know, is a very famous Nobel Laureate.
He got his Nobel Prize along with Glashow for standard model, grand unification of strong, weak and electromagnetic interaction. In addition to being a great theoretical physicist, he was a remarkable human being who was passionate about wellbeing of common people all over the world. So in particular, he said that poor countries should make use of science in their development 'cause science and technology has been helping humanity enormously over the years.
So we should not lose that talent, we should nurture it in every developing countries. So he himself was an example, you know, he did a good theoretical physics PhD at Cambridge, Princeton and he went back, was isolated. So he wanted to move that isolation. So one way is to build an institute, international center, where isolated people are brought together, get their batteries charged and then go back and perform. So that man started ICTP and I was fortunate that I went there in 1976.
I spent nearly three months every year for the next 20, 30 years. I became an associate, I became a staff associate, then I ran some colleges there, spring colleges and I also ran about 12 successful workshops because there is a very good infrastructure, good help and you could do all these things. It started with theoretical physics, which is, you know, an important component of modern science.
There are many capable people in third world countries, but because of isolation, they are not able to catch up, so bring them together. So it was doing the service extremely well and then I grew up there. So I met Professor Salam several times. I have seen him in action and his passion for people and science. So that's why I gave a talk. And it definitely helped my career.
A I said in my talk, I met my hero, P.W. Anderson at ICTP, accidentally I should say, because he gave a beautiful talk and I thought that's it. Then my host Irir Torsati came and dragged me and he said, "Anderson is free, please go and talk to him." I was reluctant to talk to him. He was too big for me. - You were intimidated? - No, he was a nice man. He is a Nobel Laureate already and he has produced Nobel Prizes. So I was kind of feeling reluctant to meet him. Then I was forced to meet him.
then that's how it began. So bringing people together is one of the important jobs spontaneously meeting comes naturally. So I was fortunate that I was in ICTP. Then I went to Princeton for three years. Again, it's a very interesting thing. In November '84, the first year I was there, there was a beautiful talk by John Hopfield, the father of neural network. John was a good friend of Phil Anderson.
Since I was already interested in biology from a distance, so I was fascinated by the talk, and in a moment of weakness, I thought I have understood what is a brain, it was one of those illusions because John gave such a beautiful talk about brain and Hebb's Rule and connections, pruning and then basal attraction and things that I could understand, relate to. So it was fascinating. Then I decided, next moment I would work on neurobiology.
So at Princeton. And when I told this to Phil Anderson, he encouraged me. He said, "It's a fantastic decision, please go." So he said, "Don't worry about doing metaphysics. You are here, we are happy, do whatever you like." So I spent two years learning neurobiology, and it's a very tough subject. I even participated in the conference at Santa Barbara. The date was neurobiology for physicists, it was a workshop. And the workshop was really special.
Only neuroscientists spoke. Even John Hopkins was in the audience. But the point is neurobiologists would make fun of physicists. They say, these physicists come and in one day make a model and get away with it. Neuroscience is really complicated. So they will tell clinical facts, this fact. So it was a good dialogue between two different communities with different views because we think some simplified model for them. Simplified models are useless 'cause for practical clinicians and so on.
Whereas for general understanding, it's important. I was spending two years very seriously thinking about that. Then high temperature, super connected to revolution broke. Then it shifted my direction and I gave up, I started working with Anderson on those problems. So those three years at Princeton was memorable in many, many respects, met great people, started thinking about great problems.
- I remember in your talk on Friday, you said that that initial trip to ICTP in 1976, because you had a travel fellowship, that that launched your career essentially. And it sounds like the place, ICTP is designed to help launch careers for those who may not be able to launch them otherwise because of where they're from or how much money they have. - Yeah, I know a lot of students attended your talk and postdocs and researchers and also administrative staff.
It was accessible to everyone, and we had a few questions sent in as follow-up. So maybe let's first play the question from Anna Kanur. She's a PSI student here. - Okay. - In a recent talk at Perimeter, you stated that in building up the International Center for Theoretical Physics, Professor Abdus Salam had a profound impact in making scientific exchange and education more accessible. But you also said that he would do things differently today.
So how would you envision a truly impactful scientific institution in the early 21st century? - Having said that very quickly, I don't know how I will do it, but let me tell you, when Salam started, it was early '60's. It's nearly 60 years ago. The world was connected by electromagnetic radiation and wireless communications but it's very different now. So let me give you one specific example that I recently gave a talk.
Salam will start, for example, encouraging private donors to contribute money and use lots of programs which are connected by suppose I had no opportunity to come from Bangalore to ICTP. I had no travel fellowship. I could have still benefited by Zoom talks because some of the Zoom talks are very inspiring, I could even talk, so that kind of things would've happened.
It is in this context I was telling you about the experience of Einstein and how it could be used in modern times to propagate signs and get people from third world countries to get deeply involved in science. So the first part of my answer is people are not able to go to ICTP or come to Perimeter, there can be Zoom talks. With (indistinct), I had a discussion and we tried very hard to implement it in India. It was called PSA mirror at Chennai.
The idea is to employ our own post docs as tutors and run the video lectures from here and get about 30 students from Chennai, just finished their master's, motivated students, and give them the same assignments, so it's mirroring it. The office was very enthusiastic and so on and then finally there was some budget crunch and then it fell down. Because of internet connections and because of this new fantastic facility, Salam will do it differently, that's what I mean.
The personal presence will be definitely good, but then in case you cannot do it, what is the next best? Then in that context, I also wanted to tell you Neil Turok has this fantastic African Institute of Mathematical Sciences and that they started something called Next Einstein from Africa. So I gave a talk in India, Next Einstein from Developing Countries. This was inspiration that came from Einstein himself.
Einstein, when he joined ETH at the Hague in Switzerland as five year course student from day number one, he collected about 10, 12 like-minded students and started discussing physics, philosophy, religion, everything every day for three hours intensely. Sometimes they came across a book by a famous mathematician Henri Poincare, great mathematician. The title of the book is "Science and Hypothesis". In fact, I have a copy of that book. Poincare was a generalist. He knew a lot of science.
So he eliminated what are the unsolved problems in science now. So three of the striking problems that he put was in Brownian motion, photoelectric effect, and is there ether? So these young minds started discussing that problem fearlessly without any inhibition and slowly dug deep and equipped themselves with enough mathematics and phenomenology. Because there are 10 people, everybody is strong in one way so they complimented each other.
In three years, apparently teachers started envying the group because these boys and girls knew more than the teachers. Then in five years, they even started writing papers. Minkowski was one of the things and Melegos was also there. For some reasons, Einstein did not get a research fellowship. He became a patent of his clerk thanks to one of the fathers of this group and then he continued in the name academia. They would meet in the evenings and discuss.
And then in few years, they wrote the famous 1905 paper on Brownian motion, relativity theory and so on. So what I said was, now I will go to a remote village, it could be in Africa or it could be in India, nothing is remote for the satellite. Suppose you give everybody a cheap tablet.
So let them sit and go to internet, all courses, MIT, Harvard courses are available, start with the element, Perimeter courses are available, and sit together every day for two hours, whatever Einstein had, whatever facilities they had, it's there in the library, so they can go deeply into it. and if such things are initiated and if they're encouraged, there'll be many more Einstein's from all over the world. That was my point.
In fact, my professor, Rangarajan in Bangalore, he was inspired by Einstein. That way, he said theoretical should be done through group discussion. Everybody has a strength and you can share it. So I wanted to say that about this Anna's question. Thanks to modern technology, there is no isolation in some sense. Like minded people can work together cause nothing like group discussion among peers because then you have no inhibition, no fear, you can ask stupid questions, no question is stupid.
- That notion that the next Einstein could come from anywhere in the world is really helped by the idea that now at relatively low cost people can do what you couldn't do. And so it opens up doors to more people. - Thanks to arranging these Abdus Salam lectures, I started going back to my lecture on Next Einstein from Developing Countries. This article appeared somewhere. I want to rewrite it and put it more accessible to people because people can think about it.
This a new power because it's also good for young minds because young children are, you know, they don't know what to do these days. They're isolated, but they can be united also through this group discussion and they can make useful things. - I think this is such an important point that technology can enable us to include more people in these discussions. And I think this leads in really well to another question that was sent in. This one is from Estelle Inac, she's a research scientist.
- Yeah, Estelle, yes. - And we've interviewed her for our podcast as well. - Oh, wonderful. - Hello, Baskaran. Thank you very much for the time that you took to talk with me and for the very nice seminar that you gave on Friday. So I have two questions for you today and my first question is the following, In your opinion, why are developing countries still lagging as far as progress in cutting edge theoretical physics is concerned?
And the second question is, what should be done to close the gap of research excellence with the developed world? Thank you very much. - We take a developing country, they have many, many problems, starting from bad politicians to water, poverty, disease and so on so they have to prioritize. Politicians always find it convenient to prioritize something else rather than education. So we have to slowly convince them.
I think it's a question of perception because the kind of vision that Perimeter has, that theoretical physics eventually helps technology, it's not obvious to people in development. They say, "No, no, we have a problem, we want a solution. We can't be waiting for 100 years" which may be relevant. So people like Estelle, you should go and convince your government, educate them, it'll take time.
For example, in my own country, soon after independence, it was realized by the leaders in those days that science and technology is very important. So unlike many parallel neighboring countries, we had some men late and if I tell the name, I don't want to be belong to any particular politics, you know, this leader by named Jawaharlal Nehru, he worked with Mahatma Gandhi for liberation now in India and so on, he envisioned that science is important, science and technology.
So from the beginning, he put money and good people, so we are reaping that benefit now. it has not happened in many other countries. It is a question of convincing people over time. And also in India, many of my colleagues complain, they are very bitter about what is happening in politics and so on. I tell them that India is an end democracy. We are 1.5 billion people. We got freedom only 60 years ago. 100 years from now will be much better. Then they get angry.
But I'm just saying that, you know, things take time, there's a time scale for everything. So we should be patient but constantly trying. - It seems like time though for richer nations is a luxury that they have because they can afford to address immediate problems, medium term problems. It seems in the developing world, like you said, the instinct would be let's fix the immediate problems right in front of us.
So how do you convince politicians to look maybe 10, 50, 100 years into the future, which is the timeframe of some fundamental science. - So for example, what I will do is there is a very famous book by former director of Institute for Advanced Studies at Princeton. The title of the book is "Usefulness of Useless Science". He hired Einstein and so on. So we have to translate such books into regional languages.
But to me, more urgent thing is to start group activity among enthusiastic children and the scientists, because Abdus Salam return from Princeton and went to his town and he was isolated. Now if Abdus Salam goes, there is no reason why he should be isolated. He can have Zoom meeting every day, two Zoom meeting, which is happening now. Then, politicians appreciate it. Internet should be used in a much more creative way, bringing people together.
- It seems like a lot of the challenges about, you know, bringing people together who maybe have different experiences, and it actually kind of reminds me of something you said in your paper when you were describing condensed matter physicists collaborating with biologists.
And so in your paper that was called "Condensed matter, Physics Biology Resonance", I wrote down something you wrote which was that, "the urgent problem facing a hardcore biologist is often very different from what a physicist genuinely interested in biology is capable of solving in a short time period." And so I think here too, you maybe have the challenge that these two types of scientists are approaching things from a different setup or a different way of thinking.
So can you maybe talk about that challenge there? - Yeah, very good. I will give you an example of Stan Liebler. So he was a condensed matter theorist, statist school mechanic in Chicago or somewhere. He slowly got into biology. Now he's at the Institute for Advanced Studies a professor of biology. He used to do wet biology.
So yeah biologist, suppose you go and tell him that this model is important, he will not, because he's working very, very hard, one Nobel Laureate from Stanford, I forget his name, he spent his whole life separating out one enzyme, one particular enzyme and got Nobel Prize, but he's not interested in the whole quantum biology or you know, holistic things. So there are people who have their own compulsions.
So you like to tell them that these things are important, you know like in nature, there are a variety of things, there is desert, there is Mount Everest, there is this and that. Imagine a world without ocean, imagine a world without desert, so it's important. In that sense, yeah theoretical biology, in the long run, it will definitely, but it has to be convinced, and it's happening in many places. Because I remember, once there was a colloquium at the Institute for Advanced Studies.
Frank Wilczek had invited some very distinguished biologists from MIT to give a talk. So he just, you know, made fun of theoretical physicists. He said, "That you guys come into few talks and you come with a model. What I'm going through today is a hypothesis which I made 20 years ago and it has taken 20 years for me to prove that hypothesis." But on the other hand, what he says is true, but then there are also people who have to see the forest from a distance and you know, it's very important.
And it's happening. Compared to 50 years ago, now biology, physics interaction is amazing. - When we first chatted a week or so ago, I was so fascinated about the conversation we had about quantum biology, partly 'cause it's an area I haven't learned much about, but also because it's the kind of thing that we can in a sense relate to because we are biological entities.
So you know, we talked about how there may be quantum processes in bird migration or in how bacteria use the magnetic field of the world. Can you speak a little bit about how biology and theoretical physics are coming together in your own work? - Okay, see I should confess that I'm not an expert. On my webpage in the institute, I don't find this, I had a sentence about myself interested in biology. It said, "Love at a distance and I am longing for a residence with her in the last 40 years."
- Unrequited love? - Exactly, well yeah, that's kind of. So two years I spent thinking of going into neurobiology but that was too short, then I came back. Since then, suppose somebody gives me a paper on "Nature" or "Science" magazine, I don't go to physics section, I go to biology to you see what is going on, just to get an idea. And also, I gave a full fledged course on biology from a very good book at my institute many years ago.
Just no equation, just phenomena because physicists are not used to it. - It was biology for physicists, this course? - Yeah, biology for physicists, it was a six months full fledged course. Bruce Alberts is a very famous biologist. He got Nobel Prize and so on. He has a book called "Essential Cell Biology", very nice book, very descriptive, so I covered the entire book for my course. So I have been enjoying it from a distance. So I have not contributed any even epsilon to real progress.
In fact, once I had a post-doc who started working with me on some issues in photosynthesis, quantum equivalence, then he left, but I seriously think about it. - It's more of a passion than your line of? - Two examples that you gave. In fact, it's almost confirmed in bionavigation, the theory due to Klaus Schulten is correct in the sense. So the challenges of falling, that is birds seem to find the direction of magnetic field in their migration. But magnetic field is very weak, one goes.
So if you convert it into some energy scale in terms of, it's one kelvin. So we are at 300 kelvins, how do you do this? So Klaus Schulten thought, it's called radical pair hypothesis. There are some chemical reactions in which a radical has an unpaired spin. So there is a biradical, two radicals. So the two spins are weekly coupled and they can form a spin singlet or a spin triplet. Spin triplet is an entangled state. A spinning triplet lets up, is a product state.
Now depending on the spin state, the reaction pathway can be very different, they can bifurcate. Klaus Schulten's point was this entanglement is sensed by a nuclear spin and then it remembers that. I cannot explain it in a very short time. So there is very important role played by nuclear spin, which is well isolated from the environment because of the weak coupling with the rest of the world through hyper fan coupling.
I heard a talk in fact some years ago at Berkeley, Klaus Schulten was sitting next to me, somebody confirming his hypothesis. It's getting more and more favorable from an experimental point of view. So in that sense, nuclear spins are very important. Every water molecule has two protons and even if you forget the spin of oxygen nucleus, proton spins are, they are like qubit, what are they doing? Some people have speculated wildly so people shy away from it.
But recently, Matthew Fisher, one of our deviants, has come up with a very concrete idea using some molecule where this entangled nuclear spin, even when they are separated, they may remain entangled because of weak coupling and it can trigger something, we do not know. So this is a kind of new friend, but people are careful for good reasons. People start speculating without doing calculations. They similar is very seriously and they say we understand everything, which is wrong.
So it is in this field, I can see in my last 30, 40 years experience, it's the experiment which is pushy. Like bird navigation, now experiments are confirming the hypothesis that Klaus Schulten made. - These processes are actually part of bird migration? - Exactly, they've done create experiments with cage and changing magnetic field, found the correlations. It's amazing. It's respected by serious people and that they're doing more and more experiments.
- From my perspective, I've always thought that quantum processes happen in a very, very small, very isolated, non-biological system that we biological animals are all wet and meaty and large and all the things that make quantum processes not happen. - In fact what you are saying is, or often people say, quantum mechanic starts at the level of bonding, then the rest is chemistry, rest are reaction rates, which was true. But however, thanks to experiments, we see surprises, like photosynthesis.
In photosynthesis, photon gets absorbed by a molecule and it gets excited, it's called exciton. This exciton people thought hops from place to place and then delivers its energy at the place which delivers an electron, so it starts an electron transfer reaction. But there was a surprise from Toronto schools and other people that the exciton remains quantum coherent over time scale than we suspected. Nature smile at people that something else happen.
Now there are many theories to convince that it is possible because after all, biology is a regulated system, we pump energy, could pump energy to keep a place cool. You know, in fact, in the colloquium that we had last week. - Was it Nicole? - Yeah, exactly, Nicole. I asked her a question because she said her quantum battery, there are applications to photosynthesis. I asked her and she sent me a pre-print.
It's fascinating because they are implicating kind of physics that they have found out at the level of single photon detection in our vision. Because it's well known that vision begins like yeah, at the level of detecting a single photon, basically it's a long molecule, it's confirmation changes from cis to trans or trans to cis. Now apparently for that to happen in a regulated way, you need some of these ideas. So it's a beginning, nobody suspected it before.
So there's a whole lot of things, again, thanks to experiments. Without experiments, we cannot make any of these things 'cause it'll become very wild because people say that our consciousness is quantum mechanical. Maybe, but who can prove it? But this photosynthesis, I was also telling you the case of only faction. In fact I heard a talk in the same Berkeley meeting by Luca Turin. So apparently in the theory of smell or in the experiments, a specific molecule corresponds to a specific smell.
So it goes and fits like a lock and key into some enzyme. Then there is a chemical reaction or a electron transfer reaction. And it was experimentally found, apparently when the molecule fits, there is no such smelling if the molecule is replaced by its isotope, for example, if you replace all the hydrogen atom 'cause the mass is different. then look at it in speculated, that somehow the electron transfer is phonon assisted tunneling.
The phonon quantile from the molecule is delivered to the electron with jumps, but it is not the right quanta. So it's a lesson in tunneling, so smelling stuff. and I was very happy to hear that that's also getting confirmed. So there are many, many small, small processes, there are many such things, you know, who knows? - So there was one that you mentioned actually in a paper that just, I was so fascinated by.
In one of the papers that you sent us, the last paragraph starts with the sentence, "Nature is remarkable." And then you give the example of a snapping shrimp, that it snaps its claw, which creates a sound, but then the sound, the bubble collapse and it actually creates light.
And I, first of all, that's amazing to me, I didn't know that shrimp could create light by snapping its claw, but this is another example of nature has been at this for billions of years and we're sort of trying to catch up with our experiments. - See, I was writing that article and my professor on his 60th birthday. I made the thesis that all (indistinct) in biology.
Then as I was finishing that paper, I came across this paper in "Nature" where sonoluminescene is been made use of by biological creatures in the deep ocean. And sonoluminescene according to this researcher was discovered 150 years ago by some people but nature had it. - Yeah, nature's been doing some of this stuff well before we even were on the scene to examine it.
- Radical pairing, similar to splitting and quantum coherence, nature has evolved and, in fact, there are serious people working on quantum biology, and of course, it's very tough field because experiments are very few, so you have to collaborate with the experiment at least. Like one mathematician, Roger Penrose, he has a hypothesis of microtubules acting like qubits. So microtubules are collection of proteins which forms tubes, they are like skeletons of the inside the cell.
They carry dipole moment. So his hypothesis is that this could, act electromagnetic mode of that could like qubit. And there are group of people who are trying to prove it. So many people say it's not possible, but there's an active discussion. So there are some latent speculations and there are some wild speculations. That's why people shy away from this field. It's not hard field with experimental evidences, someone can easily go astray. - And some people do go astray.
You know, some of these ideas, people start to think of the brain and quantum and then pseudoscience sometimes takes over. - Exactly, pseudoscience, that's the right word, yeah. I think it's okay for the public, but scientists should not get that, and also the public can get swayed, because they may start emphasizing the wrong things. I do an experiment, you should be able to repeat it.
- I think it's difficult because this area, combining two fields, you know, quantum physics and biology, you've said there's a lot of problems at that intersection that are worth studying. But then some, like consciousness, that at least for now are maybe too complicated to study at that intersection. Do you think there are some problems that will always be too complicated to study? - Ah, that's a very good question. So your question is, will humanity ever understand mind? I suspect, yes.
You know, the universe is too complex and too big to be comprehended. Think about just eight billion people, each person is own universe, his own mind, his one richness, that's one tiny dot, right? And also our own, you know, this is bacteria. The number of bacteria in our body is about five times the number of cells in the body. This came as a shock when I heard it 10 years ago during an interview. Then I started reading about it. It's amazing how we are helped by bacteria.
So there is too much to be comprehended. Even in condensed meta physics, we thought we understand salt, sodium chloride, now we don't understand this. Slowly, progress is taking place. Nature is inexhaustible and we have finite lifetime, we live for 100 years. These days some people say that from 10 years, onwards. No, everybody will live for 100 years 'cause quality of life is changing, medicine and so on. So, but you know, the universe is 13 billion years.
It's already a miracle that we are able to comprehend. As Einstein said, he can't comprehend that we can comprehend little bit of the world. - Well it sounds like you have just as many, if not more questions in your head now than you did when you were starting out - Definitely, exactly, exactly. - So a lifetime of science, but now you're left with more questions than you started with? - Definitely. - Is that part of the joy of it?
- So you understand a little bit of it, then you don't understand more and excitement continues. It's also question of training oneself. You know, I have the habit of spending half an hour every day looking at the archive. I tell young people to do that. - Oh, that's the pre-print site for all the new physics papers? - So I can't do all of them, I am very choosy, strongly correlated systems and super connectivity and quantum physics, I download few papers.
It's exciting to see how developments are taking place. It provokes your thought, you start thinking about, and some of it, all the crazy ideas are at work, so you feel happy about it, satisfied. You didn't write that paper, it's okay.
- Yeah, you know one thing that really stood out to me from our earlier discussion, you said that you have a lot of folders on your computer that contain unfinished projects and I think that's great, you know that your interests are so broad and there's so many questions and sometimes you don't end up answering them, of course, sometimes you do. I'm just curious if there are some of those projects that you look back on and find yourself still wondering about that you might go back to someday.
- Yeah, yeah, it very often happens. You think of something, you start writing a pre-print and you leave it there. You haven't forgotten the name of the paper. In fact, it's a good point I should mention because it's like a public promise. See, great Einstein wrote a paper in 1920 before quantum mechanics was born, a theory of super conductivity. Not many people know about it and a good person from Germany translated it and so Einstein's paper is in the archive.
When I read that paper, I was shocked because Einstein was so ahead of time. He says, okay, so here is a phenomena, zero resistance. I know what is Drude's law, there are electrons which are starting, they have some lifetime. And then he says totally away from any Drude's law it's something totally different. So he comes to the conclusion that our normal metal is a puzzle, it should be thought of as a perturbed superconductor. So he completely reverses.
He says, "You should understand normal metal." And that is what the game in superconductivity is. Then normal metal is very unusual it's called anomalous normal. And then on top of that, what he could think of with available resources and knowledge. So he says, okay, here is a phenomena that I see (indistinct) so how could it be? So he thinks of an electron hopping from one site to another site. Then there'll be strong, cool repulsion. Next electron will not allow you to come.
So it will push the other electron, it will push it so they'll form a cycle. So you call it as a cyclic exchange, I forget the name. So he says, under some conditions, the electron's motion will not be independent, but it will be cyclic motion, and maybe that is under that. In fact, it's very true. In fact, the whole quantum hall effect and many of these things are related to phenomena like that. So Einstein thought about it.
In fact, in the context of quantum hall, this is something ring exchange theory due to Schafer and company. So this collective cooperating motion of electrons in the form of rings is according to Einstein at the heart of super conductivity. In fact, it is related to later something called permutation cycles that happens in both systems. So I had written an article connecting Einstein's old theory with modern theory, and I just saw it yesterday.
I felt like kicking myself, it's 10 years ago, I didn't do anything. So to answer your question- - So you saw it on your computer, not published, it's an unfinished? - Exactly, it's a tech file. I started it and just halfway. - Well, maybe over time if you leave a paper for a year or five years, does your brain, you know, the things that you've learned over that time, you can approach the subject after a break from it with a different perspective? - That's right.
Sometimes, you know, I find that I was wrong, but sometimes I find I'm more right, it happens. - Well, it seems too from what I understand, that going to talks and also having discussions with people is such an important part of your research for you. you mentioned going to Nicole Younger Halpern's talk and it gave you some idea that's maybe related to some other things you have been thinking about.
And so I guess maybe that's also something that can happen, you attend to talk and that gives you an idea for one of those unfinished projects. - That's right. So for some reason I was searching for something, then I landed on my paper and it made me sad for a while, but then I said, okay, it's fine. - We've been talking a lot about how your interests are so broad, but I've been wondering if there's, is there an idea that maybe ties them together?
And maybe I'm wrong, but I wonder if the idea- - Is there an identifying theme? - Yeah, that maybe understanding emergence is somehow some kind of theme in all this work. Would you say that that's something that's tying all of this together? - Yeah, I think partly influenced by PW Anderson's career and his works and so on. Emergence fascinates me.
In biology, emergence is very obvious because you have atoms, molecules, water molecules, and then many things happen, there are insects of millions and billions types. So we say that over billions of years, these things happen. You could not have predicted next level what will happen by knowing what you know now. There is a famous evolutionary biologist by the name Ernst Meyer. He and Neils Bohr discuss emergence. Apparently Ernst Meyer was bragging about emergence in biology.
Neils Bohr said, "The whole physics is emergence." He said, "Hydrogen atom." Then he suppose, you know hydrogen atom very well. So put hydrogen atoms together, two of them, it becomes hydrogen molecule, tightly bound. Then put a water, oxygen than it become H2O. Then put few water molecules together, there is tendency to form hydrogen bound and quantum tunneling. Then put more together, you get water droplet. Then you freeze them, you get 12 phases of ice.
Then you flow, let the water flow, then you get turbulence, which is one of the most difficult mathematical problems. So you have clouds and all kinds of things emerges from oxygen and water in various associations. So he views physics as full of emergence. While people appreciate it, it was not part of the conscience of condensed matter community. It is here Anderson wrote a paper in 1972, more is different.
Actually, it was a response to some of the attitudes of colleagues saying that including great men, supposed to have said that no, now you have the right equation, the rest is chemistry. You don't need to understand anything. You know, science is done. Some great person, the end of science, you know, the rest is a matter of detail. And Anderson took that as a challenge and he said, "No, that is not true. Nothing ends, new things continue to emerge."
He caught onto this notion of symmetry breaking because you can organize many things in condensed matter, you can develop symmetry breaking. And whenever there is a symmetry breaking, there is a new rigidity that brings a new physics. And then he went across fields. He says, everything has its own important place and you cannot say that it can be discovered on its own. It needs to come from something below. And then there are surprises.
This is also I think some people call it the web of science, connection between various things. So emergence fascinates me. I can't understand my own way, emergence of consciousness and life. Life is what we see, but things like consciousness too personal and too, they call it qualia and so on. I used to have discussion with Phil Anderson. He will say that that's emergence, you can't comprehend it, doesn't mean that it doesn't exist. So people have strong views.
But the emergence that I see in my little field of condensed matter physics is mind boggling. For example, thanks to Anderson, he start identify quantum state called resonating valance ground state, which was discovered by Pauling in a different context as something very important for insulators. So he wrote it in '73, and then in the context of qupids, he brought it, fortunately for me, I was with him. We developed it and so on. Look at the way the field has grown.
People may have forgotten Anderson, but for example, one of the most complicated field in mathematics is called category theory. People tell me, even pure mathematicians call it abstract. Now, category theory, thanks to our friend Zalgon Wen who classified resonating valence ground state and then trying to organize SPT states, he used category theory very casually. Now category theory is corner of condensed metaphysics. So nobody would've thought that it'd be useful.
And once you got that, many things emerge. I can't even understand what is going on there. I wrote an article about graphene. I had a page containing quantum complexity in graphene. there is just carbon atom, then it's capable of harming SP2 bonding or SP3 or SP1 bonding. If you go to SP3, you get diamond. Then if you go to SP2 alone, then you get graphene. because the bonds are 120 degree and there is an unbonded piece at orbital, there is a hopping in honeycomb lattice that leads to daracon.
Because there are daracon, there are two daracon's, (speaking in foreign language), and the daracon's, there is a parity anomaly and there is anti Anderson localization and defects, acting like age fields and then lake effects. If you think about carbon alone, I would not have guessed that there is room for composite pharmacy So in level of few steps, you can reach that level. So I am fascinated. I think similarly, Wojciech has a very fascinating thing about emergence and liquid helium three.
In fact, I think he has a nice title that you can see the universe in a droplet of helium three, because helium three is a helium, you know, isotope of helium atom. Put them together, you get liquid helium and then they exhibit some variety of quantum phase, super helium three, Anderson phase, moral phase and so on. And to look at them, there is, you see the effective theory looks like quantum gravity. So that's a good example of emergence in one component system, Helium three alone.
That fascinates me. Even before going to living systems, animated systems offered so much variety. Now thanks to material science, so we should continue to thank our experimental colleagues. They make all kinds of materials, starting with graphene, now they have (indistinct). Each one is a miracle. People skip away and go into mathematics, but we have to listen to phenomenons, there are lots and lots of fascinating things.
- You've used that word fascinating to describe your own reaction to learning new things. I think that's what's come through in chatting with you last week and today is that your curiosity is just almost insatiable it seems, and that you have this gratitude for science and its place in your life. And that's why I think people here at Perimeter are so excited to sit down with you is that gratitude and enthusiasm feel infectious, that you're helping other people like us get excited.
- Yeah, I'm grateful to science. You know, I'm happy that I became a scientist. II also often say that I'm paid for my enjoyment. What else do you expect? I very often talk to friends that tell me, "you know, when are you going to retire? You are still studying." I have no time actually. There are no so many things to be understood and enjoyed. - You don't have time to retire. - Exactly, I have no time to retire. - That's a good way to put it.
Well, we're very grateful that you've taken the time to sit down and talk with us. I feel so inspired to read more and learn more. Thank you so much for taking the time. - Thank you very much. - Thanks for listening to Conversations at The Perimeter. If you like what you hear, please help us spread the word. Rate, review and subscribe to Conversations at Perimeter wherever you get your podcasts. Every review helps us out a lot and it helps more science enthusiasts find us.
Thanks for being part of the equation.