Fostering science across frontiers

AD: It’s a pleasure. Thank you for being here. Bhāvanā has been doing great work, so I am glad to be doing this interview with you.

AD: I had heard about ICTP already when I was an undergraduate at IIT Kanpur. After my particle physics course, I heard for the first time that in 1979 a certain Abdus Salam had received the Nobel Prize for “electroweak unification”. It was something of an inspiration to learn that a Pakistani scientist had received a Nobel Prize for contributing to a major breakthrough in theoretical physics.

My first visit to ICTP happened around 1991–92, for a school in string theory. I had just graduated from Princeton and was a postdoc at Rutgers. This was when I had the opportunity to meet Salam. He was already quite frail and not keeping in good health, but it was great to meet him in person. Of course, I had no idea that one day I would be in his shoes leading ICTP. In fact, this used to be his office.

AD: Yes, this is his blackboard. Of course, he is not responsible for what’s scribbled there (smiles). For me, Salam has been an inspiration in two ways. First, of course, because of his science. I have been working in string theory and theoretical high energy physics, on the unification of general relativity and quantum mechanics, on aspects of quantum gravity including quantum black holes and holography, which could be thought of as intellectually in the same stream as Salam’s work on unification of electromagnetic and weak nuclear interactions. Second, because of his real commitment to global science—his deep concern for science in the developing world. This is also something that deeply resonates with me.

AD: In many ways, I can identify with Salam. He came from a small town in Pakistan, went on to work at Cambridge, a major centre in theoretical physics, and was very keen to contribute to science in his home country, in Pakistan. I came from a small town in India and had the opportunity to work in theoretical physics at some of the leading centres in the US and then returned to India.

I had no idea that one day I would be in his shoes leading ICTP

Growing up in rural India, I got to see a large cross-section of the society with close friends from all strata, which I would not have seen in a big city like Mumbai. While Salam grew up in a devout Muslim household, I would describe my upbringing as basically progressive atheist.

My parents were academicians but with an unusual bent, from the post-independence generation who were excited with certain idealism about national reconstruction. They worked at a new rural university that was started as a pilot project with funding from the central government, with the involvement of some of the prominent intellectuals and educationists. The motto for this initiative was `Development through Education’ – somewhat similar to the motivations behind ICTP.

My mother taught sociology and my father mathematics. He later left the university to lead an important movement which could be best described perhaps as a people’s science movement to `demystify’ science for addressing real life situations. It eventually became very successful with engagement from thousands of small farmers, many school dropouts, who organized themselves. They mastered advanced viticulture from a post-graduate level classic book of Winkler published by the University of California and adapted the science to the local conditions with many innovations. They transformed themselves into major exporters of grapes using the latest scientific know-how which had a big economic impact in the region. These contributions and his methods received considerable recognition from some of the eminent educational thinkers like J.P. Naik, Ivan Illich and Paolo Freire and with national accolades like the Jamanalal Bajaj award. These experiences were quite influential even as I pursued a career in the abstract realms of theoretical physics.

My mother taught sociology and my father mathematics

As with Salam, it was important for me to not only do good science – it was great to be in places like Princeton where I had wonderful opportunities – but also to be able to give back to Indian science and indirectly to society in some way. Psychologically, this was very important for me. So I was really committed to returning to India while I was in the US – much like Salam, who was determined to return to Pakistan.

Of course, the times were quite different. You know, Salam joined the Government College in Lahore when he returned to Pakistan and had to spend time as the coach of their football team. The possibilities for pursuing serious physics were rather limited for him in pre-independence Pakistan of his days. When I returned to India to the Tata Institute of Fundamental Research, the situation was very different in terms of the scientific opportunities and facilities. For me, salaries and material comforts were not particularly deciding considerations. It was far more important to be able to continue doing good physics at some of the frontiers that I was interested in.

TIFR was already an internationally recognized centre in string theory. So, I never felt that returning from Caltech in the US to TIFR in India compromised my scientific career in any way. In this sense, I did not quite experience the kind of acute intellectual isolation that Salam must have experienced and which was something which provided him with the burning motivation towards founding an international hub for science like ICTP. Nevertheless, I do share this strong internal impulse with Salam in this regard to be able to make a contribution to science in my home country and more broadly to make scientific opportunities globally available.

India in the 90s or today is not quite comparable to Pakistan in the 50s. Nevertheless, some of the main challenges for building science in the developing world still remain but in a somewhat different form. My experience of working in India gave me clearer understanding and a better perspective on some of the key issues which proved to be very valuable later in my role as ICTP Director.

AD: My earlier exposure working first at TIFR and then at ICTP provided in some ways two `case studies’ which were quite important for me when I was trying to articulate to myself the mission of ICTP for the future. We all recognize the transformative power of science which can have a direct bearing upon the economic and social development of a society. Without a strong scientific base, developing countries risk being only consumers and not creators of science and its technological fruits. Thus, the ultimate goal must be to create self-reliant, strong scientific communities locally. With this same final goal in mind, for historical reasons, Bhabha and Salam followed quite different paths with different visions.

TIFR, founded by Bhabha, could be viewed as the embodiment of `Bhabha’s vision’ whereas ICTP, founded by Salam, could be viewed as the embodiment of `Salam’s vision’. Bhabha was able to create TIFR and BARC and the institutions that grew around them in India. This was possible in no small measure thanks to the unwavering support he received from the then Prime Minister Jawaharlal Nehru who had the vision and an understanding of the importance of science. This has helped create a vibrant scientific community in India.

Salam was less fortunate in getting such support from within Pakistan and was compelled to leave his home country. However, with the same impulse, he founded ICTP as an international hub for science. It works towards the same goal, but in a different way, on a more global scale by making advanced science available to scientists from all corners of the world including those from disadvantaged regions.

I regard these two perspectives as being complementary to each other. When I became the director, this complementarity is what convinced me of the relevance of ICTP in the years to come. I came to the conclusion that the vision for ICTP of the future must synthesize these two in an effective way. This has been one of my guiding principles. We can discuss this more later.

AD: What is unique about ICTP is that it manages to combine excellence with inclusion. Not only in words but really concretely. For example, when I first visited ICTP, I was coming from New Jersey, so not exactly from a developing country. I came here for the `Spring School in String Theory’ because of its excellence – because it was one of the best conferences on the subject.

Even today, the Spring school remains one of the most important events on the international calendar. Leading scientists in string theory and related topics come to lecture here on the latest developments as do some of the best students and postdocs during their formative years. But the school is open to all interested students, including from the developing world with full support from ICTP for their travel and stay. Thus, it makes these excellences more inclusive and globally available which otherwise would have been restricted to only those who could afford to come to ICTP.

It is an added bonus that the ICTP campus is in a wonderful location right next to a nature park and the Adriatic sea in the beautiful and welcoming city of Trieste. This adds to the charm and you really love it when you first come here. All of this made an impression on me.

Later on, I had another interaction with ICTP after returning to India. While I was a professor at the Tata Institute (TIFR Mumbai) we organized the `Strings 2001’ conference, for which I was one of the main organizers together with Sunil Mukhi and Spenta Wadia. It was a major conference in string theory for the first time in a developing country,¹ which in itself was an important recognition of the contributions of the Indian string community. We were able to get all the leading lights in the subject from around the globe, including Michael Green, David Gross, Jeff Harvey, Stephen Hawking, John Schwarz, and Edward Witten to name a few. It was a big challenge to organize something of that scale in India. Though we were the three main coordinators, the entire string theory community of India was of course involved and behind it, including Avinash Dhar, Gautam Mandal, Ashoke Sen, Sandip Trivedi and many others. So it was really an event organized by the Indian string theory community.

I remember visiting ICTP to seek possible funding support for this important event in India. We were grateful that ICTP immediately came forward with quite a generous grant without which it would have been difficult for us to pay for the air travel of foreign participants. Thus I once again saw the big impact of ICTP, indirectly around the world, and not only on the Trieste campus. Even remotely, it acted as a kind of lighthouse. A lighthouse for science in the developing world.

AD:

ICTP was actually a fairly small operation in the beginning. It was Salam and a few people around him. That’s how it started. By the time I visited here for the first time, as I mentioned, it had already grown into three Sections. We only had High Energy Physics to begin with. Then two new sections in Mathematics and Condensed Matter Physics were added. We now have strong sections in Climate Science and Earth System Physics, and Quantitative Life Sciences. So we have sort of responded to the time as you need both, the cosmic sciences² and the practical sciences.³

ICTP is now a mid-size research institute. At its core, it remains a place where `curiosity driven’ blue-sky research is pursued, emphasizing fundamental sciences. Even in climate science, we are more into the science of it, like modeling and so on which can, of course, become relevant for policy recommendations. ICTP has thus grown over the years with this more diverse portfolio of subjects. However, the core mission of ICTP has not really changed but, evidently, it must now be implemented very differently.

AD: ICTP has contributed to many important breakthroughs in science. A number of Nobel Prizes have been awarded for the work done at ICTP. Apart from Salam’s Nobel Prize, there is also Alexei Smirnov’s work on the Mikheyev–Smirnov–Wolfenstein (MSW) effect which gives the theoretical basis of the experimental Nobel Prize for solar neutrinos. This was all done here. ICTP scientists played a major role on the technical side at the IPCC (Intergovernmental Panel on Climate Change)⁴ and Filippo Giorgi was a co-recipient of the Nobel Peace Prize. ICTP has been part of the ATLAS⁵ and the gravitational wave LIGO (Laser Interferometer Gravitational-Wave Observatory) experiments. Also, in many other areas like string theory, ICTP scientists have made pioneering contributions.

Of course, there are many places of excellence around the world. What makes ICTP special is that it makes this excellence inclusive. It makes it global. That is the biggest success of ICTP. A related component is that ICTP is truly international, being a UN organization. We can bring countries together for advanced science even when there are political differences. For example, at the height of the cold war, ICTP was essentially the only place where American and Soviet plasma physicists could meet and discuss physics. I think these are some of the biggest achievements of ICTP.

AD: A number of colleagues, whose opinions I greatly value, urged me to consider the possibility of taking up the directorship of ICTP. I was rather reluctant at first. I was quite happy with my own research in theoretical physics and was not sure if I wanted the time-commitment. While I admired the role of ICTP, I was not overly keen to take up this major responsibility of leading such an international centre just for the sake of it.

For me, there were three critical questions. What part of the mission of ICTP still remains relevant today? What should be the essential elements of the vision for ICTP of the future, to implement this mission in the current geopolitical landscape? What effective strategy can one realistically pursue given the specific structure and mandate of ICTP? It was important to be able to answer these questions satisfactorily to myself before being convinced that it would be worth my time to take up this responsibility.

Let me elaborate a bit upon this. The need for ICTP was very clear in the 60s, because the countries in the Global South,⁶ which had just become independent after a disastrous and debilitating colonial rule, really had very few resources, both financially and scientifically. There was post-war optimism with a strong desire for international cooperation within the United Nations system. Moreover, theoretical high energy physics was viewed by policy makers essentially as an outgrowth of nuclear physics and nuclear energy which had a dramatic promise and therefore was a national priority for many countries. It is not an accident that research in high energy physics in many countries was often primarily funded by departments of energy. All these elements made it much easier to realize a center like ICTP in the sixties. It’s noteworthy that Salam himself was rather pessimistic about the chances of succeeding with something like the ICTP in the ambience of the eighties.

Evidently, the geopolitical situation and the frontiers in science are now radically different. Both these points require a serious reflection.

AD: First, one must recognize that many countries, especially the BRICS countries (Brazil, Russia, India, China, South Africa), now are at quite a different stage of their economic and scientific development. For example, India has made major investments in fundamental science, and we have strong scientific communities within India, Brazil, and China in many areas of science.

Second, as already noted above, ICTP must adequately respond to the changing frontiers of science. It was already recognized by my predecessors that ICTP must grow in other areas of science. However, there are now newer opportunities and challenges on the horizon with the developments in artificial intelligence, high performance computing, quantum information and computing. These developments have added an entirely new dimension to the notion of Open Science which must be taken into account.

From this perspective, the role of ICTP must be re-imagined. The essential inspiration remains the same for me as it was for Salam but it is natural that many aspects will have to be thought through and implemented differently. One should not merely continue by inertia with the same policies and modalities which Salam had adopted.

This introspection was quite useful for me. I came to the conclusion that ICTP is perhaps even more relevant today, and it is something where I could imagine contributing meaningfully both at the personal and institutional level.

AD: As I said before, the situation in BRICS countries is very different now. However, even in a country like India, the opportunities are not always uniformly distributed; we have some centres which are doing very well at the international level, but in some other places where there are very good people but the facilities or the opportunities for international interactions are not at the same level. Free and open knowledge exchange has always been, and remains, an essential precondition for important breakthroughs in science. So I felt that making science globally available remains a very important need even today, even within BRICS countries.

India or Brazil are not necessarily lacking in economic resources. So one cannot simply continue to parrot the rationales that were compelling at the time of Salam. ICTP must engage now quite differently, more in equal partnerships, rather than the model that was followed earlier in Salam’s time which was more uni-directional.

As I see it, the main significance of ICTP today and tomorrow is two-fold.

ICTP has a critical role to help internationalize the science even in the BRICS countries with what it can offer in terms of intellectual and scientific resources. This can be done with a greater sense of collaboration building partnerships where the financial resources can be jointly contributed. In some other countries in Asia and Africa one should engage a bit differently, not solo but with public-private partnerships involving governments, development agencies and private donors.

Another unique asset of ICTP is its global standing as an international hub for science. This is going to be increasingly important, perhaps even more so now than in the sixties, in the turbulent times that lie ahead. ICTP has the neutrality and convening power as a UN organization to bring together scientists bridging over the politics or the visa regimes. As I mentioned, even during the Iron Curtain days, ICTP was like an oasis where scientists from both sides of the curtain could come together to freely discuss science.

during the Iron Curtain days, ICTP was like an oasis

I think these two roles of ICTP, to make the excellences in science available to as broad a community as possible, remain very relevant today. Overcoming the barriers of gender and ethnicity is something that is always talked about. But oftentimes geopolitics and economics are much bigger barriers for open exchange and equity. Now we are confronting some questions with the same urgency as in the 60s but on different frontiers from climate science to artificial intelligence. For example, we have been organizing monsoon workshops at ICTP for over a decade. In these workshops, Indian, Chinese and Pakistani climatologists can come together without the hurdles from the visa regimes and geopolitical differences. Something which they are not able to do in their home countries. This is very important because monsoon or heat waves necessarily require a collective response going beyond national boundaries or political differences.

Our approach in the future should take all these considerations into account. Perhaps we can come back to it later since some of the initiatives at ICTP that we have undertaken recently are indeed informed by these considerations.

AD: It’s an interesting observation vis-à-vis India but it has more to do with local situations rather than ICTP policies. Two-thirds of women scientists coming to ICTP apparently are from the least developed countries. Yeah, I think these disparities are kind of cross-cutting. A woman living in Europe sometimes has many more privileges than a man growing up in a developing country, depending on where you are. ICTP is very committed to gender equity and is taking necessary steps on all fronts. It must be recognized that it’s a process that demands long-term commitment and sustained efforts.

AD: First of all, as soon as I became the director, COVID started. That was certainly not something I had bargained for. Especially at a place like ICTP where there are many scientists from all over the world, it had a direct impact on our mission. In fact, the pandemic in Europe broke out first in this part of Italy.

AD: Very badly. Especially this region in north Italy. It was a major challenge to deal with, and fortunately we came out of it in one piece. We were able to repatriate many of the scientists who were here at the time. This was not easy. Then we switched to online mode quite successfully, which is very difficult if you are dealing with scientists from all around the globe because connectivity can be an issue or time zones can be an issue. Then we made a decision to continue with our Masters program and successfully graduated about 200 diploma students in spite of COVID. We decided to bring them in here because doing a full year’s course online remotely, for example, sitting in Ethiopia, would have been practically impossible. Their careers would have been badly affected.

I remember that it was not an easy decision for me but it was the right decision. It was not easy to determine whether to take this risk because if you brought in students from 80 different countries and if you had 100 students each year, their vaccination status and many other cultural aspects were quite varied. Also, in the early days of COVID, there was a great deal of uncertainty. It was not practical to house them in the city since there were no buses. So there were many practical difficulties that immediately popped up.

Since there were no visitors, we decided to use the Adriatico and Galileo guest houses as a student dormitory. In some ways, for the students it was like being in a very nice prison far away from home because they were not allowed to even leave their rooms. Some had food restrictions like halal, some would crave for home food after a few days, some had psychological difficulties from loneliness and anxiety. We had to handle all this, in many ways like their local guardians. I have to really thank my colleagues, both academic and administrative, who helped make it happen, successfully graduating 200 students from over 100 countries during these difficult two years.

AD: We had some very big challenges which were more intrinsic, independent of the pandemic. ICTP’s structure was looking quite frayed both in terms of human and physical resources. During my first five year mandate, I set myself the task of consolidating and rebuilding on these fronts before thinking about any kind of expansion.

The first challenge about human resources was quite a serious one. For example, there were a large number of colleagues who had not been promoted for a long time because of certain changes in the HR policies of UNESCO. As a result, ICTP was seriously undergraded. As you can imagine, this can be debilitating for any organization and particularly damaging to a major scientific organization since we have to compete in a global market for scientific talent with the top places in the world. It was essential to ensure that ICTP remained attractive with a proper career progression for the staff.

Addressing this issue required a much greater investment of time than what I had anticipated because of the particular governance and administrative structure of ICTP. ICTP is governed by a high level international Tripartite Agreement between the Government of Italy as the host country and two UN organizations – UNESCO, and the International Atomic Energy Agency (IAEA). For our first thirty years, we were administered within the IAEA and since 1996 we have been administered within UNESCO. This governance structure has been very beneficial to ICTP since it confers the status of a UN organization. At the same time, it presents some challenges, because some of the organizational needs of a leading scientific institution like ICTP oriented towards scientific research can be quite different from the needs of the rest of UNESCO which is oriented more towards policy. If this difference is glossed over, as it sometimes was, it can lead to disastrous policy decisions.

Understanding these differences, finding a suitable framework to bring coherence between the needs of a scientific institution and the administrative framework of UNESCO, explaining them to the administrative colleagues, and advocating them to our stakeholders required some difficult diplomacy. At certain points it seemed like a hopeless and insurmountable hurdle which could seriously harm the future of ICTP.

I am very happy that in the end all these efforts were worthwhile. In collaboration with some colleagues at UNESCO, we were able to successfully resolve this issue. Very strong support from the Scientific Council, as well as from the Italian government and IAEA who are the other members of our steering committee also played a crucial role. Together, we managed to upgrade more than one third posts at ICTP to be more commensurate with the actual duties. This very substantial upgrade of our human resources was a major accomplishment for securing the future of ICTP. I was quite relieved because otherwise ICTP would have surely lost much of its attractiveness and lustre.

The second challenge has been to find the means to consolidate and expand our physical resources. The ICTP infrastructure is now 60 years old and is showing its age. We need modern infrastructure commensurate with the global standing of ICTP. Furthermore, some of the more ambitious ideas we have in mind for expanding our scientific mission will also require more funding. ICTP has been generously funded thus far by Italy, UNESCO and the IAEA, but the funding has remained constant and has not been inflation-adjusted over the past three decades. Evidently we need to look for new resources and cannot rely entirely on the generosity of public funding.

Recognizing these needs defined my second priority. We have started a very professional advancement and fundraising initiative to tap into new resources. We also have a high profile Advisory Board including people like Ashvin Chhabra, Thuy Dam, Michael Douglas, David Gross, Andrea Illy, Princess Sumaya of Jordan, Ahmad Salam. They are all actively engaged with ICTP. These efforts are also now bearing fruit and new funding is becoming available in a major way. So much so that I hope in ten years’ time this could change the equation for ICTP completely, bringing substantially more resources to ICTP than are currently available. We are therefore quite ready to start thinking about expansion.

AD: As we discussed before, we need to think anew taking the new realities into account. We need a different articulation to incorporate the newer nuances. As I see it, there are three priorities:

(1) There is a greater need to emphasize the essential unity of pure and applied science to the public and policy makers. There has been an erosion in the prestige and public trust in science now, compared to in the 60s. The importance of fundamental science needs to re-emphasized. ICTP is a living example that embodies the best elements of open science and can be a powerful agent for positive advocacy for science for its own sake and for development.

(2) There is a greater need to ensure equitable opportunities in the ongoing scientific revolution and technological advances like high performance computing, machine learning or quantum computing. This is a completely novel dimension of Open Science which now must include a notion of open access to computational resources and knowhow, open codes and open weights of trained algorithms. It cannot be good for the world if these precious intellectual resources remain locked with a few countries or a few corporations.

(3) There is a greater need to ensure essential global participation to address global challenges like climate response. This existential threat to humanity does not respect national boundaries. At the same time, climate research is often constrained by geopolitics. For an effective global climate policy, it is paramount that those who are most affected are part of the science that informs policy.

This articulation suggested to me three strategic priorities for ICTP.

(i) ICTP 2.0: Reinforce the existing competencies of ICTP, and build upon these core strengths by attracting the best talent to ICTP. Modernize both the physical and scientific infrastructure of the Centre.

(ii) International Science Alliance: Build partnerships with foundations, governments, corporations and private donors from around the world to deliver more effectively on ICTP’s programs by bringing in new sources of funding.

(iii) International Consortium for Scientific Computing: Develop an institutional framework and partnerships for Open Computing.

AD: As I mentioned, ICTP can be a major force for re-emphasizing and advocating the role of fundamental science for development and international cooperation globally. For this to be credible, the core of ICTP needs to be strong and we need to expand wisely both in terms of human and physical resources. This is what I mean by ICTP 2.0.

For any organization, the most important resource is people. For a scientific organization it is all the more important to find the top talent doing the most exciting science and to ensure working conditions that are welcoming. As I mentioned, securing the promotions of our scientists was therefore an important first step. Evidently we need to continue along this path, actively seeking out the best talent in the frontier areas. I am also glad that we are now beginning to change the gender ratio as we make new appointments. The fraction of women among the professional staff has increased from \frac{1}{5}th to \frac{1}{3}rd in the past five years with some excellent scientific appointments.

The frontiers of science have also changed. We are no longer looking for the Higgs particle. In addition to particle physics, there are exciting observational projects like the Square Kilometer Array or gravitational wave telescopes of relevance to primordial cosmology and astroparticle physics. The theoretical explorations could also be oriented towards understanding machine learning, or the new developments in quantum information theory and computing, or neuroscience or automated proof verification or the fascinating connections between quantum entanglement and spacetime geometry. These are exciting frontiers.

For any organization the most important resource is people

We also started the new programme of International Chairs whereby renowned scientists can spend a total of one year at ICTP so that our global community can benefit from the scientific interactions with them. So far we have had Don Zagier and now Carolina Araujo as the Ramanujan Chair, Subir Sachdev on the Virasoro Chair and Sergei Gukov on the Mirzakhani Chair.

Of course, it is equally important to upgrade our infrastructure to offer world-class facilities to our global community. This is also a part of our thinking for ICTP 2.0.

AD: As a first step, I was very grateful that the Italian government came forward with a grant of 10 million euros to renovate the ICTP campus. The Euler-Lagrange lecture hall complex is already beautifully renovated and we will be working on both the Leonardo and Fermi buildings. This has been a real shot in the arm.

Another major success is the very substantial grant of 15 million dollars which we received from the Simons Foundation International (SFI) to create a Science Complex. The iconic Adriatico building is a natural destination for such a complex. It is in a wonderful location just by the sea and has been an integral part of the ICTP experience. But we have been paying a very high rent which is already becoming unaffordable. Moreover, it is now seriously in need of an upgrade. We would like to create a world-class Science Complex not only for accommodation but more broadly our scientific activities that is commensurate with the global standing of ICTP.

The grant from SFI will enable us to achieve this goal. The grant is structured in an interesting way as a challenge to raise a matching 15 million in five years. It is one of our ambitious goals to raise these matching funds, and I’m reasonably optimistic that it will happen. That will really change the way we operate. We are grateful to SFI and their President David Spergel for this generous support.

Another very important development is our project for modernizing the Library. This has been a public-private partnership with some funding coming from Italy and some from friends of ICTP like Drs. Ashvin Chhabra and Daniela Bonafede-Chhabra. The paradigm of a library has now completely changed around the world with digitalization. It is no longer merely a place where books are stored but rather a space for creative thinking and collaboration. We managed to flip our collection so that now our library has over 50K digital books in addition to 50K physical books. All ICTP associates from anywhere in the world get to legally download any of these books and keep them. This is a wonderful implementation of “open science”.

All these developments have been tremendous for ICTP, and are going to be truly transformative.

AD: I imagine the `International Science Alliance’ as a broad umbrella to change ICTP’s way of engaging with the world, for the reasons I’ve explained. For example, at the time of Salam, we had memoranda of understanding with hundreds of universities such as Tribhuvan University in Nepal or University of Mumbai in India. These universities surely benefited from the ICTP identification and with some kind of international recognition but without a really big commitment of funds on either side.

Now, my efforts have been to think a bit differently at the national or regional level to build an `alliance for science’. Such umbrella agreements with a national-level funding agency or a ministry or a foundation can broadly benefit anybody from that country or the region with real funding. It is also more efficient since we don’t have to work with several individual institutions.

This initiative is now beginning to gain some traction with foundations, governments and also private donors. For example, foundations like the Arab Fund and the Kuwait Foundation have made substantial new funding available to ICTP for supporting science in the region. One of the important successes recently is the MOU⁷ we signed with the Ministry of Science, Technology and Innovation of Brazil. It was an honour that ICTP was invited to sign this document with Minister Luciana Santos in Brasilia during the state visit of President Sergio Mattarella of Italy to the Brazilian President Lula. We were discussing this alliance with colleagues in Brazil for the last two years and it was good to see it reaching the level of maturity that it could be signed in the presence of two presidents. All said and done, ICTP is a small scientific institute. It’s not a ministry. So we were honored to be given this kind of a platform. And that has now given us an opportunity to really interact with the funding agencies in Brazil CNPq (​​Conselho Nacional de Desenvolvimento Científico e Tecnológico).⁸ I’m excited about this collaboration which could blossom.

We are currently discussing the modalities with President Galvão of CNPq. If Brazil makes a substantial contribution within the framework of this agreement, ICTP is of course not going to keep the money for itself. If somebody gives an X amount of money, ICTP contributes Y, both directly and in-kind. It’s a win-win situation with a multiplier effect. We have over 6,000 scientists coming from over 100 different countries every year. And we get about 30,000 applications. So, as such, we cannot accommodate all as we have only limited resources. With the International Science Alliance, it would be easier for us to increase the number of scientists or increase the number of students coming to our programs.

This is what I mean by a reciprocal partnership. There is excellent science happening in Brazil and we are now collaborating on many fronts, and funding is not necessarily an issue as it was in the past. At the same time, there is no substitute for actually going to conferences and talking to leading international experts in the field, and getting inspiration to conduct one’s own research. Brazilian scientists therefore are glad to have ICTP as a partner where they can interact with the international community more easily than in Brazil.

I think that this is a new direction that ICTP has taken and we are beginning to see some success. We have taken important steps also with South Africa, Rwanda, Vietnam, Indonesia, China. I do want to realize something like that with India. I have been talking to the Secretary of the Department of Science and Technology Abhay Karandikar, and also the Ministry of Environment and other colleagues. I am optimistic.

It has been heartwarming to see also the support from the scientific community itself for supporting the initiatives of the Alliance. Just during the past year, we have been fortunate to receive over a million euros collectively from several scientists or former scientists connected in some ways to ICTP, including from many of the leading lights. This is a strong validation of the mission of ICTP.

AD: Computation has now become the third pillar of science together with theory and experiment which was the traditional paradigm for science. Artificial Intelligence presents huge opportunities as well challenges and perhaps so will quantum computing in future. If these amazing technological tools at these frontiers do not become available to the developing world, then I think the knowledge gap is only going to increase. Thus, if we are serious about Open Science, I really regard it as an obligation for an institution like ICTP to make computational resources and the know-how globally available.

Now, this is something that ICTP cannot really deliver on its own. It’s too big a task. Which is why we launched the International Consortium for Scientific Computing, ICOMP⁹. Some of my colleagues at ICTP like Sandro Scandolo have played a crucial role in these developments. ICOMP is conceived not as a Centre or a section but as a consortium transversal to all sections with many partners. For example, we now have agreements with South Africa, with their national supercomputing facility and the National Centre for Theoretical and Computational Sciences (NITheCS). This will allow any scientist in South Africa, irrespective of which university, to come to ICTP and benefit from the programs offered here. We have an agreement with IBM to launch two major schools and two major prizes each year in machine learning and quantum computing. We have an agreement with CECAM (Centre Européen de Calcul Atomique et Moléculaire),¹⁰ one of the international supercomputing collaborations based in Switzerland to make computing resources available to the developing world.

Within ICOMP, ICTP would be the central facilitating node. We have strong domain expertise in many computationally intensive fields such as climate modeling, renewable energy, computational material science, AI, or quantum information. The consortium will harness and amplify the capacities. I really think that this idea has great potential. It will require new resources and considerable investment but it is something worth focusing our energies on.

This initiative can really help to connect the global north and the global south to make new technologies like GPU, Artificial Intelligence, or Quantum Computing broadly available and to address critical problems like climate response.

It is essential that the global south is sufficiently prepared with a strong scientific community. This is very important for downstream applications. For example, you may have a sophisticated climate model using GPU programming or AI developed in the Bay Area or in Bologna. However, if one wants to predict the rainfall in Ghana (whose economy depends heavily on hydro-electricity) for policy recommendations, it is essential that there is a climate and computational community in Ghana who are part of the creation and implementation of this model adapting it to the local conditions. Otherwise, it would be like a black box and one cannot have the public trust and support for the national policy decisions that follow from it. Both the International Science Alliance and ICOMP can play a role here and I think ICTP has a special niche given our global network of scientists and track record.

AD: We are primarily a theory institute. One might say ICTP is like CERN but with a Black Board instead of the LHC. But we do have some necessary facilities for computation and instrumentation.

We have a computing facility with the `Argo supercluster’ which is important for our programmes for high-performance computing for training and development. For actual computations, we have an agreement for cloud computing with CINECA (Common Infrastructure for National Cohorts in Europe, Canada, and Africa),¹¹ the national supercomputing facility in Italy which is among the top in the world. With ICOMP, we would like to see that these resources grow both for training and development onsite, and for cloud computing.

We also have a Science, Technology and Innovation (STI) unit. It’s a relatively small unit but they do a lot of interesting and creative things such as low-cost measuring devices in collaboration with CERN, and with IAEA, which are very useful in the developing countries. For example, for climate modeling, you need data for simple parameters like temperature and humidity but with a large coverage. Even if you have a sophisticated climate model, without this data for initial conditions, it cannot be sufficiently predictive. Large parts of countries in Africa which are not covered adequately, low-cost instrumentation of the kind that the STI unit provides can surely help to improve the coverage. So ICTP has some role to play in these directions.

AD: I would say that it’s a stroke of good luck that our campus is at this amazing location in a wonderful city like Trieste, which is also not overly expensive. The quality of life is high. You can go to the mountains or you can go to the sea. In summer, you can just go to the sea in front of ICTP for a swim at lunch time and come back to work. This does add to the attraction of ICTP.

it’s a stroke of good luck that our campus is at this amazing city like Trieste

In fact, when people were looking for a place for ICTP, there were many possibilities. ICTP could have gone to Florence, for example, which is also a special city but perhaps not from a practical point of view. In an expensive big city, bringing in 6000 scientists would have been challenging with a major cost overhead. Being where we are makes the logistics a lot simpler. Apparently, Trieste received support from the non-aligned countries including Yugoslavia and India because of its geographic location at the East-West border. In some ways, the character and history of Trieste as a city at the East-West frontier rhymes with the international spirit of ICTP. The natural beauty of the location also adds to the charm of the ICTP experience. People remember their stay here even 20 or 30 years later not only for the science but also for the experience.

AD: I’ve had a productive collaboration with Sameer Murthy and Don Zagier. It didn’t start here as such, but I met Sameer for the first time at ICTP when he was a postdoc here and I was visiting from TIFR. We got to know each other and we started to talk. Then I invited him for a postdoctoral position in Paris when I moved to Paris. As you know, scientific collaborations often get started in a very informal way. Sameer and I were worrying about some problems in the theory of quantum black holes to count the number of microstates of a particular set of black holes in string theory. It turns out that the number of microstates for this set of black holes is given by the Fourier coefficients of a meromorphic Siegel modular form or alternatively a meromorphic Jacobi form.

Recall that a classical modular form is a function of a single `modular’ variable \tau. A Jacobi form is generalization to a function which depends on an additional `elliptic’ variable z and thus is a function of z and tau. The theory of Jacobi forms is very well understood when they are holomorphic in z. There is a classic book by Don Zagier and Martin Eichler on the topic. Since we were naturally encountering these objects in our investigations about black holes, I had organized a conference in Paris together with Boris Pioline on this theme of `Black Holes and Modular Forms’. The idea was to bring together physicists and mathematicians who otherwise would not talk to each other. I didn’t really know Don at the time, so had invited him just on a hunch which turned out to be quite fruitful.

AD: Yes, in Paris. So we were discussing it in a cafe after one of the talks, that the Jacobi form that one encounters in the black hole problem is not holomorphic but is meromorphic: it has poles in z. Sameer and I thought that with help from a mathematician like Don we could hack our way to figure out the right way to deal with these poles. But then Don said, “no, no, it is not such a simple matter of just dealing with a pole. This actually goes back to some deep mathematics and is related to the mock theta functions that Ramanujan introduced in his famous last letter’’. People have been puzzling about these functions since 1919 for years without really having a theory. But then he said, “you know, luckily for you, Zwegers, my former graduate student, has been able to give a proper definition of these `mock modular forms’ which are related in a very precise way to meromorphic Jacobi forms’’. So we started to collaborate. I thought that we would be able to figure things out in a few months. But then it turned into a five-year long serious mathematical collaboration with many new mathematical results and also a complete solution of the physical problem. We wrote a big paper,¹² almost 150 pages long. And then Cambridge University asked us whether we want to publish it as a book. So now we will publish it as an advanced monograph in physics. That is something we have been working on even before coming here.

AD: Correct, but then it so happened that I came to ICTP. And then so did Don. As mentioned earlier, I had started this new program of International Chairs to attract top scientists to ICTP for one year spread over 3–4 years. We offered him the Ramanujan International chair¹³. I have seen Don in action and I would say that his way of thinking is akin to that of Ramanujan. He is really somebody who enjoys working with numbers, and has a remarkable ability to see patterns in numbers.

to bring together physicists and mathematicians who otherwise would not talk to each other

I enjoyed working with him because in some ways he thinks like a physicist. He really wants to compute things. He is very hands-on and not an abstract mathematician like someone from the Grothendieck school. On his 65th birthday, when I was invited to give a talk, I started with the quote from Freeman Dyson who had said that mathematicians are of two kinds. There are birds like eagles who have a panoramic view of deep mathematical structures and then there are frogs, who love the specific mathematical details ¹⁴ It is not intended as a pejorative but as a description of the style since Dyson considered himself or someone like Ramanujan a frog. And of course there are some like Euler who are perhaps both. I would say he is a frog extraordinaire.

ICTP did play a role in many ways. As I said, I met Sameer here for the first time. Then Don and I joined hands once to organize a two-week long school at ICTP on modular forms and physics. So ICTP should get some credit for our collaboration. We continue with the writing of the book which is still not finished. And the three of us have continued to collaborate on different topics where physics and number theory meet. So I think it has turned out to be a very fruitful collaboration.

AD: As you know, a modular form is a holomorphic function that is highly symmetric. It is basically invariant (with some weight) under the action of the modular group {\rm SL}(2, \mathbb{Z}). As a result, it is sufficient to know just the first few Fourier coefficients of a modular form to determine it completely. This is the power of modularity.

A mock modular form is holomorphic but not obviously modular. What makes it interesting is that it is `secretly modular’ in that one can add to it a non-holomorphic `correction term’ to obtain its `completion’. The completion is modular but is no longer holomorphic. This secret modularity and the incompatibility between modularity and holomorphy is the essence of mock modularity.

To give a geometric analogy, a holomorphic modular form is like a blue circle. It is both blue and circular – invariant under the symmetry group of rotations. A mock modular form by contrast is blue but is not quite circular. It is rather like a circular arc which lacks the symmetry of a circle but in an interesting way. One can add a missing arc or the correction to obtain a complete circle as its completion. However, imagine that this correction piece must be red for some reason. As a result, the completion, even though circular, is no longer fully blue. Thus, there is a secret circularity if one is willing to give up on blueness, and there is an incompatibility between circularity and blueness.

What was magical about Ramanujan’s discovery was that he was able to grasp the secret modularity underlying the mock theta functions without explicitly knowing about their completions. This is what made these objects mysterious until the theory was developed by Zwegers.

AD: One of the main results in our paper was to show that, following the work of Zwegers, that the meromorphic Jacobi form admits a canonical decomposition as a sum of an Appel–Lerch sum which has the same pole structure and a mock Jacobi form which has no poles. A mock Jacobi form is a new class of functions which we introduced in this work. It is related to mock modular forms in the same way holomorphic Jacobi forms are related to ordinary modular forms.

Sameer and I found a beautiful physical interpretation of this main theorem. It turns out that the Fourier coefficients of the mock Jacobi form count the number of microstates of single-centered black holes and the Fourier coefficients of the Appel–Lerch sum give the number of microstates of multi-centered black holes. So many of these mathematical objects in the story turn out to have a nice physical realization.

The mock Jacobi forms, like the mock modular forms, are not quite modular, but by adding a non holomorphic completion term, one can obtain the completion which is modular. The assertion that such a completion exists was the nontrivial part of our theorem.

The apparent lack of modularity of the mock Jacobi form is what had bothered me to begin with. For a mathematician like Don, modular symmetry is something sacrosanct, and seeking the modular completion was quite natural. However, one can ask why physics should care about modularity, or the modular completion. My motivations were quite different coming from what is known as holography. In this particular context, I knew that the {\rm SL}(2, \mathbb{Z}) modular symmetry must be a part of global diffeomorphisms because of holography. Diffeomorphism invariance cannot be violated in a physically sensible theory of gravity. Thus, the modular symmetry turns out to be sacrosanct also from a physical point of view. Thus, these very different motivations turned out to be closely related.

The physical origins of this apparent lack of modularity were still not completely clear. In a subsequent paper with Putrov and Witten, in a quite unrelated context, I was able to relate mock modularity to the non-compactness of field space of the underlying path integral for a conformal field theory to get a better physical understanding of mock modularity.

AD:

Well, it was an interesting experience. These topics in number theory were pretty far from my interests and kind of exotic when I started, and I never thought I would go down this track. This was the first paper in my life with a theorem in it. It was a fun collaboration though and I learnt a lot from Don. I think he too enjoyed talking to physicists and learning about quantum black holes. He was thrilled to see this sudden connection with something totally unrelated to mock modular forms.

It’s not always easy to strike such a successful collaboration in such widely disparate fields. Sometimes the tribal pride of being a physicist or a mathematician comes in the way. I think it’s a bit like learning a new language. One has to be a bit adventurous, prepared to sound silly like a beginner and willing to listen, and not be overly embarrassed about making mistakes to learn a new language and then start speaking it fluently.

AD: Yeah, Don is here. He likes Trieste so much that he has bought an apartment here. We are very happy that he has been with ICTP. The Ramanujan chair is for some fixed duration. But we would be happy to try to keep him in a different capacity at the center.¹⁵ He would also be glad to be spending time here.

AD: Yes, in Brazil and Rwanda, not South Africa.

AD: We did this partner institute experiment, and its best implementation is in Brazil. What we have learned from that experiment is that one has to go into it only after careful consideration. I think it can be done in India too. I have had discussions with IIT Bombay to begin with, and we have a memorandum of understanding to start a centre for excellence which could grow into some kind of a partner institute. I am discussing it.

The really important thing is not so much to go for a centre, but build a partnership with scientific exchange first. One really needs to understand the needs and the funding situation, local support, support from the government, and the available leadership and human resources. If any one of these components is missing then it can become a difficult operation. I do hope that we succeed in developing a major collaboration with India as I have had with Brazil and one can then think of more ambitious projects within that framework. I think it’s very much a possibility, and I would really like to see it happen.

AD: For our 60th anniversary, we wanted not only to celebrate the past but also to prepare for the future. Apart from the main event on the Trieste Campus, we have had several events around the world, including at the UNESCO headquarters in Paris, IAEA headquarters in Vienna, in Brazil, in Vietnam, and in the US. I was very glad that the Italian government put forward a resolution in the executive board of UNESCO for the celebration of this important milestone supported by some 28 member states. Next month we have an event at the UN headquarters in New York. These are excellent opportunities to showcase ICTP’s contributions and promise to the member states and to build the ICTP community around the world.

AD:

We got wonderful testimonials from many ICTP scientific alumni from all over the world. For example, consider Raji Mamade from Ethiopia who was a diploma student at ICTP. He worked with me for his master’s thesis over the summer on quite advanced topics in holography and string theory and black holes. He then went on to do his PhD at MIT. He explained how the ICTP program was really critical for his growth as a scientist. Or, consider Nana Klutse who was an associate of ICTP. She is a professor at the University of Ghana. She came to Paris for our celebratory event at UNESCO. It was an impactful testimonial by a leading climate scientist from Ghana, working in Ghana, making important contributions to the scientific reports of IPCC (Intergovernmental Panel on Climate Change) with this strong connection with ICTP. All this amply demonstrated the achievements of ICTP for creating a community of scientists around the world at different levels.

AD: It has been a unique experience to be leading a major international center of this kind with such a special mission. It has been both a challenge and an opportunity. It is not just a scientific institution. I mean, I would be happy to work at such an institution just for the excellent research, but perhaps not to take up the directorship. The mission of ICTP is what makes it special because it is something very close to my heart. It offers an even broader platform not only to contribute as an individual scientist but to contribute to global science especially in the developing world. What little I’ve been able to accomplish in this direction has been deeply satisfying.

little I’ve been able to accomplish has been deeply satisfying

I have a second mandate now for another four years. I hope that we are able to allow ICTP to grow and be an even bigger force in the 21st century and have a much bigger impact. The 60th anniversary was an occasion to imagine ICTP in 2064. Some of the ideas and our vision I have are outlined here and also in my presentation during the celebrations in Trieste.

AD: I’ve been following Salam’s advice to leave the morning free for physics. I have instructed my secretariat to avoid taking morning appointments. If you get really concentrated three or four hours in the morning, that’s a good time for creative thinking. So I’ve been able to continue working on some interesting physics. For example, the work with Witten and Putrov mentioned earlier was done after I became the director. Recently I’ve been quite excited about the connection between quantum entanglement and gravity and am glad to be able to find enough time for research.

One of my main hobbies is Indian classical music. I play the north Indian classical violin. I have been a disciple of Pandit Atulkumar Upadhye from Pune for many years and try to keep it going. Amir Khan, Kumar Gandharva, Kishori Amonkar, Bhimsen Joshi, Nikhil Banerjee, Vilayat Khan are some of my favorite classical musicians. Swimming in the Adriatic and hikes in the Alps near our home in Slovenia are some other modes of relaxation.

It’s indeed a challenge to combine different things in life, but I think it’s a matter of time management to find a balance. You learn to do that at different stages of your life. I guess everybody does it in their own way to balance their time for science, for personal life and for society.

AD: Well, I actually take credit for this idea [laughs] so I’m glad you asked this question. Upamanyu Moitra, an excellent physicist and a very energetic collaborator of mine, who was previously a postdoc here wrote these plaques explaining H bar and Psi Bar. When I was the head of the section, there was this little unused area. So we got it a bit spruced up as a discussion area and called it “Hilbert space’’. Just some physics humor!

AD: (Laughs). That’s a good question. I’m glad that you noticed this. Yeah, we thought of lambda bar which would be like a de Broglie wavelength, but I think it was not so catchy. Then my colleagues in condensed matter introduced the Fock¹⁶ space in their corridor following Hilbert space.

AD: Well, I don’t take credit for it. I had a very good friend, Utpal Lahiri at IIT Kanpur. He was really into languages and later went to MIT to do his PhD in linguistics. He wrote all these names in different languages when we were undergrads. I have had it since those days. Then I learnt how to write in Korean while visiting Seoul. It’s a pretty easy script conceptually similar to Devanagari. Then I had some postdocs and colleagues from Japan and Georgia who added more languages. So now there are few new ones.