Astral Odyssey: Thesis Journeys Part 5

In a riveting interview, Gagandeep shared his deep dive into the realm of black holes and gravitational waves. His thesis, under the guidance of Prof. Nils Andersson and Dr. Kinjalk Lochan, focused on exploring super-radiance and quasinormal modes through scalar fields.

1. What was your thesis topic ?

 Exploring super-radiance and quasinormal modes of Black Holes through scalar fields. 

2. Who was your guide ? 

Prof. Nils Andersson, University of Southampton Local guide : Dr. Kinjalk Lochan

 3. Why did you choose ? 

In the summer after the third year, i.e. 2022, I worked with Prof. Nils on rotating black holes. I found it very fascinating and wanted to explore the realm of black holes. I told this to my supervisor and he suggested that we can work on exploring the properties of black holes, thus extending my summer internship into a master’s project. 

4. What did you like about it? 

My thesis exposed me to the field of theoretical astrophysics. Black holes have always been a subject of fascination for me and I got the opportunity to explore the field. Although it was a review thesis, i.e. I did a review on the works already published in the field and nothing original, I learned about the research in the field of theoretical physics. During the summer of 2022, I came across a phenomenon, the ”Penrose Process” and it blew my mind. It talks about the possibility of extracting energy from a rotating black hole. In my thesis, I extended upon this and studied a better phenomenon, Super-radiance. Better as in it is more easily observable than the penrose process. We can find frequencies of the fields surrounding a black hole that may undergo super-radiance and thus extracting mass and spin from the black hole. These fields can form a cloud around a black hole that may radiate gravitational waves, whose detection will provide us with the information about these fields. To work on the models of the gravitational waves from the system of the black hole and the (scalar) cloud, I needed to understand the concept of detection of gravitational waves, so in the second half of my project, I worked on the quasinormal modes of black holes. Detection of gravitational waves is dominated by these modes. 

5. Was Astro always the plan? 

Yes. Ever since middle school, when I learned about planets and stars, I was tempted to study astronomy. Different documentaries and shows only increased my interest in the field. Even though attraction towards the Universe and space at that age does not necessarily means that you want a career in the field, as it can just be some naive fascination with the stories of the explorers, but it drove me to study physics at IISER Mohali. At IISER, I took various Astro courses, attended a few seminars and completed some courses on different MOOC platforms. It made me realize that I am interested in the theoretical aspects of Astrophysics and Cosmology, so I chose my thesis project accordingly. 

6. Internship done in this field ? 

In the summer of 2021, the summer after my second year, I worked on the special theory of relativity, its applications on mechanics and optics under the supervision of Dr. H.K. Jassal. Next summer I worked on the general theory of relativity and rotating black holes under the supervision of prof. Nils Andersson. I continued on this the next year i.e. 2023 during the summer and the thesis. I also attended a few conferences, seminars and summer schools like ICTP summer school, IAGRG School on Gravitation and Cosmology which were online and a little difficult to follow for a master’s student but I got to know about the current research being done in the field. 

7. Any mistakes that you have done, and would recommend the juniors to avoid? 

One of the mistakes that I made was not working on anything after the first year. Even though it was difficult at that time due to Covid, I could have got some project if I had started to look for the opportunity a little early. So, I would like to suggest that start looking for internships as early as possible. During the first two years, you can explore on different opportunities and different fields but try to land on a path that is best for you as soon as possible. Another thing is that even if you want to work on theory, try to gain some experience with computation and observations, basically try to develop different skills. This will only help you in a long run. Also, choose your supervisor wisely. If you are doing your thesis outside of IISER Mohali, then make sure your local supervisor is helpful and understanding. 

8. What are your future plans?

 Currently I am continuing my work on the models of gravitational waves through the system of super-radiating fields and rotating black hole under the supervision of prof. Nils Andersson. And in the future, I will look for a PhD in the field of theoretical Cosmology as I want to continue on this path and remain in academia. 

--Avni(MS22)