New Year's Eve!

Maintaining the tradition of spending new year's eve in the capital, I am "planning" to leave for New Delhi tomorrow. I am saying "planning" because there is still chances of this trip getting ruined. There are some strikes going on in Rajasthan through which my train is supposed to pass through. The Gujjar community there are protesting against the government by blocking rail and road traffic. Their demand is around 5% reservations in education, jobs etc. Anyone can imagine how ridiculous the way of their protest is. As far as their demand is concerned, I would say all the Indian citizens should get reservations so as to remove the existing bias as well as to rule out such stupid agitations in future ;) My train has been diverted from the usual route I guess, and hopefully I will be able to reach New Delhi before new years' eve. The dense fog around the capital is another problem hitting both rail and air traffic. I am still optimistic about reaching Delhi somehow. I have to leave for Calcutta also for a workshop in SINP from 4th Jan-8th Jan'2011.

Rajasthan 2010

I was in Jaipur for around one week attending a conference in LNMIIT as mentioned in the previous post. The city of Jaipur has got tremendous historical importance and the number of monuments in and around the city are still carrying the pride of Jaipur and the kings who ruled there. First of all the whole city is surrounded by hills and on top of the hills you can see various forts and huge walls. The ancient city of Jaipur was slightly away from the main city today and it was surrounded by huge walls. The fort of Amber was simply amazing. The beautiful ceilings inside reminded me of some of those in Vatican museum. It was great to see the Rajasthan Government taking all necessary steps to keep the monuments evergreen. Apart from the this grand fort, the Jalmahal, the Jaigarh fort, the Nahargarh fort, the Hawa mahal, the City Palace were also amazing. Jaipur don't look so good from the point of view of a modern city, but it has got so much historical monuments that no other city in India can probably beat Jaipur. And the interesting fact is that most of the cities in Rajasthan have such huge monuments which make Rajasthan a hot tourist spot in India.

Apart from historical monuments, Rajasthan is famous for wildlife also. Bharatpur Bird Sanctuary and Ranthambhore Tiger Reserve are pretty famous for that. Bharatpur is around 4 hours journey by bus from Jaipur. It's a small town, a bit dirty and unorganized. But the autowala took us to a nice place to stay. It was a part of a person's residence which he gives to tourists on rent. It was pretty close to the gate of the Keoladeo National Park (or Bharatpur Bird Sanctuary) . We went inside the sanctuary twice: we walked on the first day and took bikes for the second day. Although the sanctuary is spread over an area of 30 square kilometer, most of it were unavailable for tourists. Apparently a tiger came out from Ranthambhore national park and entered into some village from where people drove him off to Bharatpur. The authorities are yet to transfer that tiger from Bharatpur to some other national park. People said , it would be done within one week and the entire park will then be open for visitors. We saw a wide varieties of birds there mostly unfamiliar to me. The Siberian Cranes for which the park was very famous at one time, don't come nowadays. According to a guide there, since the Afghan war started, those birds stopped visiting the park since their route to India was over Afghanistan. Apart from birds, there were deers, antilope, wild lizards, jackal and lots of cows, bulls.

Ranthambhore national park is around 190 km from Bharatpur. And there is no good bus service between these two famous tourist destinations. We had to take some pathetic train to reach Sawai Madhopur (which is the district center and very close to Ranthambhore). Sawai Madhopur is again a very small town, but fact that the town has more number of hi-class hotels than shops surprised us a lot. We need to survey a lot to find a room which fits our budget. The Taj Group , the Oberoi group also have hotels over there. And due to high demands from lots of tourists, the prices of rooms were a bit high for Indian grad students ;) Anyway, we managed to find a small tent for us at 600 rupees per night. We took two safaris there, one in the afternoon and one in the morning. Although the afternoon safari went in vain (in the sense that we could not see any tiger), the morning safari made it possible. The guide is the second safari was a bit more experienced than the first one. He followed the warning calls from spotted deer and sambar deer and lead us to spot the tiger. The tiger quietly came and crossed our roads. We felt so lucky to see it in the very second safari, people don't see tiger there even after taking 4-5 safaris. The park is spread over an area of 392 square km and there are only around 30 tigers. So the probability of spotting a tiger in a 3-hour long safari is quite low. Apart from tiger, we saw many birds (which we already saw in Bharatpur), crocodiles, deers, antilope etc.

Area-wise Rajathan is the largest state in India, and of course it's not possible to cover everything within just few days. There are many more interesting places like Jaisalmer, Jodhpur, Bikaner, Ajmer which we could not cover. Will have to plan some trip again to this awesome Indian state in near future :)

DAE Symposium Jaipur

DAE symposium 2010 was in Jaipur this time as I had mentioned earlier. It was held in a brand new institute called L N Mittal Institute of Information Technology (LNMIIT), around 17 km away from the main city. The institute campus was really cool, and the organizers also did a great job I believe with the arrangement of food, accommodations etc. There were two things I did not like about the campus: it is located in a very deserted place away from the city and the campus has too many flies which keep annoying you in the lecture halls as well as in the dining room. The symposium brought many old friends together, it was really nice for me to be in a conference where more than half of the participants are known. Most of them, I met in various other schools in the last few years. This symposium was also very exciting for me since it was the first time I gave a talk in a conference. Although I was a little bit nervous, but my talk went quite well. Each day of the conference was divided into two sessions: one for plenary talks and the other for parallel sessions. The invited speakers for plenary talks were well-known experts in their respective fields and it was really great listening to them, particularly the talks by Sandip Trivedi, A Joshipura and others. Anyway it was a great academic experience for me. The non-academic experiences of Jaipur will follow this post shortly ;-)

Symmetries at High Temperature!

When I read about the spontaneous symmetry breaking (SSB) in the simple scalar field theory, I was wondering many things. In SSB, what happens is that, the ground state of the scalar potential breaks the symmetry but the overall Lagrangian still preserves it. I was wondering if the reverse is possible and if yes, then how will we describe it. My curiosity was natural in the sense that we see more conserved symmetries at low energy like color (strong interaction), electromagnetism, baryon number, lepton number etc than spontaneously broken symmetries like electroweak symmetry. Although we know theories where Lepton number and Baryon number can be violated by the decay of very heavy particles, at GUT (Grand Unified Theory) scale for example, but we always take it for granted that the conserved gauge symmetries like color and electromagnetism at low energy are conserved at high energy as well. However, recently I found some papers which try to investigate such issues in details, the high energy behavior of symmetries. And it can be possible that finite temperature effects can:

1. Restores a symmetry (global or local) at high temperature which is broken at zero temperature and

2. Violates a symmetry (global or local) at high temperature which is preserved at zero temperatures.

Although the first effect of finite temperature is what most of us would naively expect (like in the case of SSB), but the second effect is something counter-intuitive as well unexpected. The second effect is known as Anti Restoration of symmetries at high temperatures. Langacker and Pi had shown in their work that the U(1) symmetry of electromagnetism which is perfectly conserved at zero temperature can be broken at very high temperatures provided your theory has sufficiently rich to account for that. Of course, with just the standard model field content, the second effect would be difficult to show. Although such anti-restoration at high temperatures wont be observed at present universe which is in a supercooled state, but such effects can have very important implications in cosmology. There might be multiple phase transition in the early universe because of this restoring and anti-restoring effects. There are models where the electroweak symmetry is broken at very high scale (~GUT scale for example), and as the Universe cools down, this symmetry gets restored after some critical temperatures and upon further cooling, it gets broken at the electroweak scale. This means that the standard model quarks and leptons were ultra-heavy at very early stage of the Universe which can have various implications. Although this field was very active in the eighties, I do not see anybody working on such models seriously nowadays except the models of supersymmetry breaking. But I find these ideas very interesting although they are kind of out-dated from current research trends point of view.

Delhi proved it once again!

Commonwealth games brought a vast difference to the capital city of India in terms of infrastructure, road, transport, quality of living etc. The successful completion of the games put a very good impression of the city at international level. But better roads, better way of transport do not always mean that the people are good and Delhi has proved it once again. Delhi has maintained the top position in the country probably for a long time in terms of crime against women. It is considered to be one of the most unsafe city for women in India. That clearly shows the typical mind-sent of common people towards women there. The day before yesterday there was another incident of gang-rape in the city. And this time also the victim was a BPO employee. No wonder that states like Haryana which is the worst sufferer of problems like female foeticide, honor killings, dowry and all neighbors the capital city. Until the people change their mindset, develop a little respect for women I doubt if such incidents can be stopped by strict law and order. Delhi has a mixed crowd, people from various parts of the country come there for various purposes. Out of them, may be the number of people coming from the seven north eastern states is the largest. And the crime against north eastern women is also largest. Apart from the most heinous act of rape, there are many incidents of racial abuse also. And north eastern people who look different from the people of rest of India fall prey to such racism very easily. People call them "Chinki", a disgusting word which I came to know of when I went to Delhi for the first time to pursue my BSc. When I introduced myself to couple of friends in the college and told them that I am from North East, their first reaction was how come I don't look like a chinki. People are so used to these words that they don't even think this could be a racist word. You can't make fun of people with their looks, color etc. But it's hard to convince people. Most of the time I give up when I try to convince anyone that these words make fun of people's look and we should not use them. But the same people reacted like anything when there was racial attack against Indians in various cities in Australia. Racism of any kind and anywhere is intolerable and I regret to say that Indians also suffer from it in their country. But it always goes out of notice to most of us, people think the abusive words are just for making fun. They are not only abusing the north eastern women, but at the same time they are making them look like alien to the rest of the people in the city. They feel lonely, insecure because of this and the most unfortunate ones become victims of the most heinous act of rape followed by murder sometimes. We can't always keep blaming the law and order situation, government, police for failing to provide safety to the women in a city. We, the people have to change and develop mutual respect towards our fellow human first.

CDM vs WDM

I have been a fan of CDM(Cold Dark Matter) since I learned about dark matter and and it's particle interpretation. By "Cold" it simply means non-relativistic at very early stage of the Universe ( = when it decoupled from the thermal equilibrium and got frozen whereas other standard model particles were still in equilibrium). Their mass can vary from a few GeV to TeV. People who love supersymmetry, would always bet for CDM since supersymmetric models naturally provide a CDM candidate without any ad-hoc assumptions. R-parity, a discrete symmetry which is ad-hoc in Minimal Supersymmetric Standard Model (MSSM), but naturally arises in gauge theories where B-L is a part of the gauge symmetry (Left-Right Symmetric Models for example) makes the CDM perfectly stable. Thus it can satisfy both cosmological relic density constraints as well as structure formation bounds.

Although CDM has been taken most seriously among other Dark Matter interpretations in the last 2-3 decades, there is no experimental evidence yet which can confirm CDM over others. And this slightly discouraging fact demands us to be a little open minded. I recently read a paper by Manfred Lindner et al (Physical Review D 2010) where they have talked about Warm Dark Matter in Left-Right Models (LRSM). Warm means slightly lighter than CDM (mass of the order of say keV) and hence they could be relativistic for a long time. And the most natural candidate is sterile neutrino which naturally arise in LRSM as a part of the Right handed doublet. But since, they are considering non-SUSY models, the stability of sterile neutrino is not guaranteed and hence they have to fit the parameters in such a way that the life-time of the lightest sterile neutrino exceeds the age of the Universe. Although this does not look elegant like in SUSY models, but this is a good alternative and it does not cost you too much. You have far less free parameters compared to SUSY models and it will be easier to rule out or confirm such models in the experiments. In this paper, the authors are focusing more on how the keV scale sterile neutrino DM can satisfy the cosmological bounds as well as neutrino oscillation data. And they have shown it does, although with some undesirable features like one active neutrino becomes too light ( 9 orders of magnitude smaller than 1 eV, but still allowed from neutrino oscillation data).

Apart from cosmological and neutrino oscillation bounds which are of course the most crucial test for a dark matter candidate, there should be a way to actually observe it. The ongoing direct detection experimental results, I don't think we can fit with a keV sterile neutrino. The indirect detection experiments like Positron excess will be even harder to fit with such WDM candidate. But in any case these indirect detection experimental results have other astrophysical explanations and the various direct detection experiments don't agree with each other. Even if LHC gives clue about such keV sterile neutrino, we still wont be able to say if it is the true dark matter candidate or not. We still have to rely on direct detection experiments, provided all of them agree with each other. Anyway as G. Bertone commented in one of his recent review (to be published in Nature), we can not keep on proposing more and more experiments to search for dark matter endlessly, if we do not get some positive signal in coming few years, may be there is a need of paradigm shift and we need to look for alternative scenarios. The worst such alternative to me would the MOND theories. They look so ugly to me that I wont ever be able to believe Nature surrendered herself to them!

DAE Symposium 13-18th Dec'2010, Jaipur

Finally my trip to Jaipur next month is finalized. The abstract I submitted got accepted for an oral presentation. I will be presenting my paper with the PRL guys on D-parity breaking and TeV scale left-right symmetry (http://compactified.blogspot.com/2010/06/arxiv-number-2.html ) . This is going to be the first conference where I will be giving an oral presentation. I am a little scared but I already have enough of such presentations in IITB, so won't be a big deal I guess. Apart from the main results of the paper, I might include some other stuff also which could be a mere proposal at this stage since I have not completed those studies in details. I am looking forward to meeting couple of old friends as well as some well-known people in HEP from all over India. Apart from that Jaipur is one of the hottest (not in terms of temperature :P) tourist destinations in India and most importantly I have never been there except the train station through which my train passed through on the way to Delhi many times. If time permits I am planning to go to Ranthambore, Bharatpur also. These are very famous for wildlife (specially tigers and migratory birds). December will be very tight it seems as I am also planning to come to PRL, Ahmedabad after the conference for some work. I am not at all sure about new years eve party this time. I might not be able to celebrate it in Delhi like in last couple of years. Hope it happens once again. Keeping my fingers crossed right now.