## Week 2 at TIFR

Yesterday marked the end of my second week at TIFR. I’m slowly getting acclamatized to life here and the rather hard routine of going to bed at 10:30 PM and waking up at 6 AM. I now understand why Dr. Suresh told me that being bused in is, in some ways, a good thing. Maybe my body will learn to go into deep sleep real fast, at last.

That apart, the food here is slowly getting boring, my project is slowly progressing with a lot of back-tracking (like those progress bars on most applications – the KStars conjunction tool for instance – that seem to make time travel in the past a reality), and I’m learning stuff.

This week started off with some more reading of Frisch’s book on ‘Turbulence’. I finally managed to start Chapter 6, on Kolmogorov theory. Early this week, I had a long discussion with Prof. Spenta Wadia, which eventually gave me an understanding of Functional Integrals, the Feynman Path Integral formulation… He loaned me his copy of Feynman and Hibbs (Quantum Mechanics and Path Integrals) from which I learnt the basics of the path integral formulation of QM. I think it’s a nice idea. He said he’d also teach me the Dirac equation sometime for fun.

We were trying to write part of the Navier-Stokes equation as a potential energy. I even came up with a solution, that I realised was incorrect because of an extremely stupid mistake I had made – I had written the convective derivative which is $v^i \partial_i v^j$ as $\partial_i v^i v^j$ which is zero for an incompressible fluid! For a whole day, I thought I was right and we tried to put in Lagrangian multipliers into the potential to fix the $\partial_i v^i$ appearing in it. When I realised my mistake yesterday, I was looking for other possibilities and realised that no “local” potential is possible. In the evening, my guide told me that it was not possible because the field was not curl-free in the first place to get a potential term! We’re now left to deal with more complicated stuff, and in the meanwhile I’m going to continue my reading of Frisch’s book and Srinivasan’s articles on turbulent flow. But the point of this exercise for me, was that I learnt something – and I got a feel for what research might look like.

Recently, there were two interesting colloquia here. I attended a talk on the LHC and the Dark Universe by Dr. Rolf Heuer, Director General of CERN. He had pitched it at a low level, so I could understand a fairly large part of it. There was yet another colloquium by Dr. Atsuto Suzuki, Director of KEK which I attended, in which Dr. Suzuki talked about Neutrino Telescopes, the Solar Neutrino problem, and the Super-Kamiokande and KamLAND neutrino detectors. Again, the talk was at a popular level, so I could understand most of it. The departmental introduction talks for VSRP students ended this week, with the last one being the Theoretical Physics department. I learnt quite some stuff there as well.

I also went to Dr. Umesh’s labs, where he did his research to earn his PhD, and built quality instrumentation. He also showed plots of electron scattering by Hydrogen molecules that showed the Young’s double-slit interference due to the two hydrogen atoms, which he had talked about in our class. I also saw parts of the Pelletron from outside. I hope to visit the Petawatt LASER lab and the Pelletron some time.

I’m now trying to find ways to spend the weekend.

## My first week at TIFR

Today marks the end of my first week at TIFR. So far, this place has been amazing. Let’s make a quick summary of plus points and minus points:

Work environment:
I’ve currently settled on a desk in the students’ room with my laptop and just enough space to keep my books. Air conditioned, Wireless net access. I’m surrounded by a lot of PhD students. They work a lot and that’s good because it motivates me to work as well. It’s so nice to see the next generation of scientists pacing up and down thinking, occasionally writing a few equations (that interestingly seem at least remotely familiar!) on the board. I like the work environment, although sometimes I wish it were cleaner – but after all, I’m used to dirty desks!

Lectures and other stuff:
We’re currently hearing from various departments about their work. So far, we’ve heard from 6 departments. Some of the speakers were very impressive, while some were talking to their colleagues and not to students – making their talks drab. Today, we heard from the condensed matter physics group, and we also had a nice discussion after the talk. I’ve been learning something new, something totally different everyday!
It was interesting to see a non-scientist at TIFR saying “You should always try to do science with enthusiasm.” or something carrying a similar message, as he fiddled around with an interesting experiment saying, “The scientists at TIFR have done this to me!”. I enjoyed the fact that learning about the world around is so enjoyable – to everyone.

My project:
My project’s about hydrodynamics. My guide et al found new symmetries in the non-relativistic Navier-Stokes equation for incompressible flow. The symmetry group is the conformal group. Given the generators of the conformal group, I verified today that the Navier-Stokes equation is indeed invariant under the action of the infinitesimal generators conformal group. My summer project will be related to these symmetries.
Today, when I went to meet Prof. Spenta, the discussion drifted to Green’s functions. He explained to me what a Green’s function was in brief (I still need to think), and eventually pulled out a functional integral and said “This is what’s called a Feynman Path Integral”. I said, I don’t know this stuff. And the reply was approximately, ‘Yes! That’s the point! You don’t know this stuff – so try to think about it and reconstruct it – don’t read about it’. He’s always put in the point that the best way to learn things is to think about them and reconstruct them, and not by reading them up in the past few times I’ve met him. I liked that! I’m now left to figure out all by myself what a special conformal transform does, and how a certain Feynman path integral gives me a two-point correlation function!
In the last one week, I also learnt a lot from Frisch’s book on Turbulence.

Food:
Well, I have the choice of 4 canteens! That’s much better than IITM. I don’t complain. Food here is good. The only stuff I don’t like about it is the garlic. It feels great to have nearly authentic Mysore Masala Dosa in Mumbai! We don’t have a choice for dinner, though, and I nevertheless manage to eat roughly the same stuff every evening.

Peers:
My co-VSRPs in the Theoretical Physics Dept are pretty good too. I’m yet to interact with most of the PhD students. I have knowledgeable peers to discuss stuff with.

Accomodation:
We’re accomodated in a furnished apartment at a place called Wadala, which is an hour’s journey by road from TIFR. That’s a little pain, but the accomodation isn’t as bad as we thought it was initially. I feel it’s better than hostel back at IITM, but I do miss internet connection. It doesn’t matter that much because I get just enough time to sleep at the accomodation and spend the rest of the time at TIFR.

I did feel a bit homesick initially, but that’s the case with me everytime I face change. It’s something that happens when you don’t give your brain enough work – but I now have enough to pack my day already!

Overall, I rate the first-week experience as good 😉

I’m going home this weekend and returning on Sunday evening. Our department will introduce its research activities on Tuesday, and I’m looking forward for that!

I completely subscribe to what your guide said about reconstructing things. You get to have lot of fun when you rediscover things. And yes, it is not always true that you will have time to reconstruct things you need yo understand, so make the best use of this time 🙂

Hello
Can you please mention about the entrance tests and interviews for admission(Ph.D. Physics) to TIFR ? I am referring to the kind of questions asked etc and how to prepare.
Thanks

SIR CAN U GUIDE ME ABOUT HOW TO PREPARE 4 THE EXAM (INTEGRATED PHD ,BIOLOGY)
THANKS

## Summer Project Decided!

Yes! 😀

This summer, as I stated in an earlier blogpost, I’m going to be working under Prof. Spenta Wadia and Prof. Avinash Dhar at TIFR as a part of VSRP 2009.

I met Prof. Wadia today and decided the details of my project. I will be doing a “pure” fluid dynamics project, at least on the outset. Prof. Wadia’s group has discovered a new symmetry in the Navier-Stokes equations that was unknown earlier, and my summer project will be closely connected to that.

So far, my initial task is to read the book on “Turbulence” by U. Frisch. It’s quite amazing that concepts from the Dynamical Systems course that I did under Prof. V Balakrishnan last semester are used in this book’s description of turbulence, and I’m glad I did that course. Somehow, it turns out that I can understand that book, although I feel that it is of a pretty advanced level (it’s meant for graduate first years, but we’ve done those required courses now anyway). Frisch also discusses the symmetries in the Navier Stokes equations pretty neatly. I’m still going through the second chapter and will need an understanding of 6th chapter for my work – so there’s some good lot of reading coming up. But the book is really interesting. He presents intuition and phenomenology when required.

Overall, I’m happy with the project.

Congrats on the project!

## Heading for Two months at TIFR

I’ll be heading for Mumbai tomorrow to join the Visiting Students’ Research Programme [VSRP 2009] at TIFR.

I will be studying Theoretical Physics under Dr. Avinash Dhar and Dr. Spenta Wadia. My summer project is going to be on ‘Fluid Mechanics from Gravity’, which will eventually merge with my BTech project.

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