Dr Swapna Mahapatra explains the context of her research in string theory and takes us through her forty year-long journey in the male-dominated field of high energy physics.
Dr Swapna Mahapatra. Credit: The Life of Science
Professor, head of department, director of research and development, dean of science – “You see, I have several responsibilities at same time,” chuckled Swapna Mahapatra, a high energy physicist who joined Utkal University in 1997. Patient and calmly self-assured right from the outset, Mahapatra seemed to carry the burden and honour of leadership roles with relative ease.
Of course, like any administrator in a State university, her schedules are generally chockablock with classes and meetings. Yet, Mahapatra promised me half an hour of her time and stood by her word. Without rushing through questions, she explained the context of her research in string theory and took me through her forty year-long journey in the male-dominated field of high energy physics. It was only an hour later, when she was alerted that a contingent of scientists had arrived for her next meeting, did she excuse herself.
When HEP became hip
The 70s and 80s were spine-tingling times for high energy physicists around the world. Aided by technological advances such as particle accelerators, they were making great progress in understanding what primary particles make up the entire universe and what kinds of interactions can exist between them.
Four fundamental interactions/forces exist – electromagnetic, weak, strong and gravitational – and the big question was whether the theories for each could all be ‘unified’ into a single theory that can explain the working of our universe. In 1983, CERN discovered the W- and Z-boson – the particles which are responsible for the ‘weak force’. This was a big step forward in the goal for unification.
The excitement was infectious and it did not spare 23-year-old Mahapatra, who was just commencing her PhD at Department of Atomic Energy research establishment Institute of Physics (IOP). “I had heard couple of talks on unification of fundamental interactions during my MSc and also during my PhD coursework and it fascinated me. That’s why I decided to work in high energy physics.” The reason these discoveries come under the umbrella of “high energy” physics is because larger and larger amounts of energy are required to zoom in to particles that are tinier and tinier (yet have high mass), she explained.
The central section of the UA1 experiment (during which W and Z bosons were discovered) on display at the Microcosm museum at CERN. Credit: Wikimedia Commons
With the W & Z-boson discovery, two of the four forces – electromagnetic and weak – were successfully unified into the ‘electroweak theory’. Mahapatra joined the movement to accomplish the next two steps. “I worked on how strong interactions can be unified to give a Grand Unified Theory (GUT), and also how gravity can be incorporated into that. This is called supergravity theory.”
Mahapatra’s work is theoretical; and very often; it is theoretical predictions that direct the design of experimental set-ups because it tells the scientists what they should be looking for. “For example, the electroweak theory (unifying electromagnetic and weak interactions) was proposed long back in the 70s by Sheldon Glashow, Abdus Salam, and Steven Weinberg. They won the 1979 Nobel Prize for predicting the existence of w-boson and z-boson particles which mediate weak interactions. But to understand mass of these particles, physicists needed an extra particle – the Higgs particle. All three of these are now experimentally verified.”
A GUT (that merges the first three forces) is not yet a reality. However, merging strong interactions is still considered a more attainable goal than merging gravity, the fourth force. Gravity is still relatively mysterious and so it seems like an alternative model is required to unify all four into a theory of everything (TOE). To Mahapatra, string theory seems like a good bet to get there.
All strings attached
She delved into this sub-domain of high energy physics during her postdoctoral research at TIFR, Mumbai and Institute of Mathematical Sciences, Chennai. This was when string theory was still very new in India. “Unlike imagining particles as points, string theory assumes that everything starts from a string,” she explained. “Electrons and other fundamental particles are just various modes of vibration on a string. What emerges from this is very different and interesting.”
Driven by the fast moving nature of the field, Mahapatra spends a lot of time making sure she is up to date. “If you ask me if whether there are any experimental signatures of string theory, I’d say there isn’t any direct evidence, but there is lots of indirect evidence.” She pointed out the example of the supersymmetry theory which predicts that every particle will have a supersymmetric partner particle (with a spin that differs by half of a unit, for example bosons and fermions) that can explain a lot of gaps in the reigning Standard Model. Supersymmetric particles are also a key ingredient in string theory. The pieces of the puzzle as starting to fit.
The implications of Mahapatra’s research lie in cosmology too. “String theory is going to answer some profound questions in cosmology such as ‘what is the entropy of a black hole?’, ‘how can we understand the thermodynamics of a black hole?’, ‘what happened in the first few microseconds of the beginning of the universe?’, ‘what is the nature of dark matter and dark energy?’, ‘why is the universe dominated by matter?’.”
It’s no wonder that after all these years, high energy physics continues to hold her fancy. “Various branches of physics come together – gravitation, cosmology, hydrodynamics, string theory, supergravity, supersymmetry, even condensed matter physics – everything is now interrelated!
Timeline of the metric expansion of space. Credit: Wikimedia Commons
Born in the city of Cuttack in Odisha, Mahapatra was brought up in a very academically-inclined family. One of her aunts was a mathematician in Berhampur University, another was a psychiatrist, and her father was a professor of Odia literature. “My mother was also a student of science, very interested in chemistry. But she was too shy to protest getting married. She became a housewife. It was her dream that I should do well in education. They gave me full freedom to study whatever I wanted,” she said.
Physics being her strongest subject, Mahapatra decided to take it up with a BSc (honours) at Ravenshaw College (now University) in Cuttack. “Those days, all good students would go for physics,” she recalled. She continued there for MSc, despite there being better institutes she could have moved to. “Masters there was [just] okay. Utkal University was much better but I was in Cuttack, and you know how it used to be in those times… they tell women ‘if there is a college here, why go to Bhubaneswar’. It was not like today. Now things have changed unimaginably.” But she insists that she has no regrets – “After all, now I’m here, right?”
For her PhD, Mahapatra finally made the big move out of home to IOP in Bhubaneswar. Towards the end of her PhD, she got married to fellow physicist Karmadeva Maharana, who was a faculty member at Utkal University till he retired in 2011. Postdocs in Mumbai and Chennai followed.
In 1996, Mahapatra’s research career got a boost with a prestigious Humboldt Research Fellowship. She spent the next year in Humboldt University in Berlin. The fellowship lasts for two years, but when Mahapatra got an offer from Utkal University one year into it, she decided to return to India. A permanent position at Utkal felt like an offer she could not refuse because it was a good institute and her husband was there as well. They had already been apart for more than five years. Moreover, she stressed that options were few back then. “There were no NISERs (National Institute of Science Education and Research), IISERs, IITs were few… and it was tough to get positions in universities.”
Nevertheless, her ties with the European high energy physics scene remain tight. “There is a provision in the Humboldt Fellowship that if you have not completed your tenure, you can make several visits. I have to utilise my summer vacations for this (collaborations) as the rest of the year, there is lots of teaching and administration work, especially now!”
Balancing priorities
The building where Mahapatra works in Utkal University. Credit: The Life of Science
Mahapatra admitted that she would have loved to spend more time doing research, but state universities are generally not the best place for this. “I’m not very happy here [in terms of research] – see, in state universities, you don’t get much facilities and you spend much more time teaching. HODs have the same workload as any other faculty… But you have to give something up when you get something else. Our family needed us. We don’t have children but we want to be here to look after my parents and in-laws.”
Because of obligations to the university and to her family, Mahapatra’s visits abroad are no longer two and three months long as they used to be. “When I go, my people in Cuttack feel insecure, so I go away for a maximum of one month these days.”
For this physicist couple, not having children was a conscious decision. “We wanted to focus on physics. People will find that crazy now, but at that time my friends also had similar ideas. Somehow, this younger generation does not think in this way. If I had children, I would not have been able to go for postdoc. This field is very demanding. You have to give 100% to remain in the field because you need to keep track with what is happening if you want to contribute. This means spending lots of time to understand even a single paper. You need to be totally devoted.”
So does that mean that high energy physicists should not start families? “I’m not at all saying that. I always tell my female students, ‘if you find a good person please go ahead. Never think of what I will say. It’s your life.’ Just that if you want to get married or have children, you need family or people to support you.”
In Mahapatra’s department, one-third of the students are women. “Still you don’t see so many at the highest levels. That’s because many are pressured to get married.” So she advises her students to be very firm, as she had to be. “I had told my family that I won’t get married because I want to do physics. But very few families will accept that.”
The role of state universities
Mahapatra is proud about the tradition of good research that her department has cultivated. “We got accredited A+ this time by NAAC. Very few state universities manage this. We worked very hard for this,” she said. She is also pleasantly surprised with the amount of applications her department receives every year. “We are receiving about 1,300 applications for 30 seats. Most are from Odisha or West Bengal”.
A significant fraction of the students at Utkal, according to Mahapatra, come from financially poor backgrounds. “These students are interested in science but could not afford to go for engineering or medical coaching classes. Utkal doesn’t compare to IITs but here we publish in all SCOPUS journals – which have good impact factors.”
“Our students are very good. They don’t remain unemployed. Many have gone to various places all over the world as postdocs and now they are faculty members all over the country. That says that our teaching is good, the atmosphere is good. We motivate them, mentor them, give them exposure to a world outside of Utkal University. It’s part of our job.”
High energy physics is a male-dominated field, Mahapatra affirmed. “But somehow, I have not felt any discrimination. The people in my field give me lot of respect. They know I have struggled a lot to be and continue here. I have tried to keep my dignity and work hard to stand up in the field with whatever limitations I have. It feels nice to be in this field.”
This piece was originally published by The Life of Science.