by Panos Charitos. Published: 15 September 2013

During Dinesh Srivastava's visit to CERN we had the chance to meet him and Tapan Nayak and discuss how the field of heavy-ion physics developed over the years, the participation of Indian institutes in ALICE as well as the meaning of being a good teacher.

Is there a growing interest in heavy-ion physics in India?

Well, I would say yes. I remember that when we started in 1988 no one was working in Quark Gluon Plasma while today there are more than 200 people actively working in the field. There is also a rather strong community of 50 – 60 theorists including students. This change is also reflected in the number of meetings that are often hosted in various institutes across the country while many of them are specializing in various aspects of the study of the QGP and heavy-ion collisions.

Do you think there is a balance between theorists and experimentalists?

I found this question particularly important and as director of a research institute but also as a theorist I am trying to grasp the right answer.

What should be noted is that Indian experimentalists in ALICE as well as in other experiments have thrived because they are coming from a very successful mix-up of home-grown theorists and home-grown experimentalists. I think this is particularly important and I would say a key to success that has to be acknowledged.

Of course, these days there is an increasing trend in the number of positions for experimental physicists and I believe that many of our students are often influenced by this fact when they face the decision about their career path. Nowadays, there are fewer and fewer postdoc positions in theory and this also holds for faculty positions.

It seems that experimentalists are also preferred for teaching positions. However, theorists can be  equally good as teachers and I believe that the nature of their research helps them in certain respect as they have to use an analytic method. In that context they can be extremely efficient in transmitting new concepts and ideas to the students.

Now to return to your question one can see that there are fewer theorists and especially in heavy-ion physics. Think for example that no Indian theorists recently visited CERN to work in heavy-ion physics. I hope that in the next years we will be able to change the situation and I am thinking how we should establish a formal way for doing that.

Perhaps, one step towards this direction is that the Indian government agreed to invest a sufficient amount of money in trying to set up a Centre for Nuclear theory. As director of a laboratory that covers almost every aspect of nuclear physics - from low energy to nuclear structure and intermediate nuclear physics up to high energy heavy-ion physics – I think this is a unique opportunity not only for theoretical physics but more broadly for the community of Nuclear and High Energy physicists in India. For any further development in the field more theorists are needed as they can offer useful insights to the experimentalists.

Last but not least there are two more reasons why I think it is important to invest in a new generation of theorists: The first is related to the new computer facilities that we have that allow large computations that are often needed in our field. The second is the strong tradition that India had in many of these fields like for example the study of nuclear structure. I think that this tradition gives an advantage that should be further exploited. Finally, I would like to add that I would appreciate a bit more theory contribution in heavy-ion physics given also the strong participation that India has in high energy particle physics.

Dinesh Srivastava visits ALICE at P2. From left to right: Satyajit Jena, Tapan Kumar Nayak, Dinesh Srivastava and Paolo Giubellino.

What was the biggest surprise from what we have learnt from the study of strong interactions?

Well, many unexpected things happened in the course of the study of QGP and in developing Quantum Chromodynamics. In the past I tried to compile in a way all the things that theorists didn’t expect even in their wildest dreams. As I see it now I believe that we should be more open and ready to see new things coming.

One example from my personal experience is related to the event by event fluctuations that have been observed both at RICH and the LHC. I believe this is a wonderful confirmation of quantum mechanics; a wonderful demonstration of the quantum description of the nucleus.  

Another example is perhaps the study of the elliptic flow. In a way it is an observation that was not explicitly expected. For the first time we had a hydrodynamic description of the collision describing both nuclei and we were the first to predict that the photons will “see” this elliptic flow. However, although there is a qualitative description of this phenomenon, no theorist has so far been able to explain it quantitatively. This means that there is still some lacuna in our understanding of the structure of the QGP and how it evolves.

Dinesh Srivastava with Tapan Kumar Nayak, Paolo Giubellino and Satyajit Jena in the ALICE Cavern.

To conclude I believe that the study of QGP remains a very interesting field. Looking back one can see that we have moved from the early days when all we had was a speculative understanding to an era of quantitative description. This step was possible thanks to the relentless efforts of large groups of people. It is a very nice feeling and I am happy that India participated in this step.

After almost one year as director of VECC what are your feelings about your new post?

Being head of an institute with certain administrative and financial powers is a big responsibility but  also a great opportunity; an opportunity to remove the bottlenecks and try to make things work in a more effective and faster way.

Of course I do regret not having more time that I could dedicate to my personal scientific research. However, I think it’s an important job that someone has to do even though it means that you have to make some sacrifices. I honestly believe that with the right administration you can also contribute to the scientific endeavour, giving more opportunities to young scientists and try to make more efficient the work done by your colleagues.

Which are the qualities that you think are the most important to be a good teacher?

First of all, as you may know, in India the teacher is a sacred person. She/He has to be immaculately honest and with a low ego. The teacher has to realize that he is really prospering and developing only if his student is better than him. The student has to do something better than his teacher and the teacher must make it happen.

Moreover, She/He should be friendly and avoid scaring his students or competing with them. Students should feel able to discuss with their teachers their dreams and their nightmares. It is often the case that students share their personal and family problems with their teachers as they trust their advice.

Many of my students were coming to my family’s house sharing not only their scientific but also their personal problems and dilemmas. I think that almost all successful teachers that I know in India have a family-association with their students. So I think that it is a true blessing to have a good teacher. At the end when you ask students why they choose to study science you will find that the most important factor is the inspiration they got from the high school teachersf. On the contrary, if the teacher is not enjoying what he is doing then he will never be able to teach his students. As a quote that I often use says: “only a lamp can light another lamp”.

What are your plans regarding the collaboration between VECC and ALICE?

I think our collaboration with CERN has given us confidence, exposure, and most importantly a hunger to do better. It has inculcated a resolve to keep doing front line basic research. It also gave us exposure to detector building, modern management, modern computing, e.g., grid, etc. It has taught our colleagues a way to form a team where individual egos are subsumed into the activity of the group. The satisfaction of having participated in the discovery of the Quark Gluon Plasma and its properties cannot be over-emphasized.

I look forward to VECC participating in building the forward calorimeter for ALICE and to having a larger GRID centre at VECC. I would like our students to continue to participate in the experiments and analysis of data at CERN. I also hope that our theory persons as well as students also get to work regularly at CERN as they are already doing a good job and interacting with the international community will help them become better. Specifically, regarding the physics of ALICE, I should mention that we specialize in photons, jet-quenching, hydrodynamics and heavy quark production and propagation, all that ALICE will continue to study.

Finally, I should mention that I find exciting the possibility that India might become an Associate Member of CERN. I am quite sure that we can make valuable contribution to ISOLDE, RD51 and a large number of accelerator activities.