Saturday, October 31, 2009

Meeting with Supervisor after three Months..;-)

Tomorrow I am hopeful of catching up with my PhD supervisor as he is visiting his home institute for two days. I met him in the first week of August, since then there were around 15 email exchanges between us related to various stuffs. Although he managed to give couple of useful feedbacks regarding my paper (which I have recently submitted to PLB) , I am not being able to work much towards my next paper. I always feel, I need to do lots of live discussions to clear doubts and move ahead which is hardly a reality. And my supervisor is so busy with non-academic activities that he hardly replies to my mails. Sometimes I get replies to some mails sent around two months before. I do not think I am smart enough to carry on my research like that. I always feel like communicating this to him, specially from next semester point of view. This semester at least I am finishing my coursework although not being able to do much research , but in the next semester I have no purpose of staying in the campus if my supervisor is not here. The problem is that he is going to McGill on sabbatical for the next semester, which again gonna screw my research. I have spent two semesters already here in the campus (autumn 2008, autumn 2009) without much progress in my work as my supervisor was in a different institute. I just do not want to make such a repetition in the next semester. It's two frustrating to spend days without any useful work. Let's see what happens tomorrow, just keeping my fingers crossed.

Friday, October 30, 2009

May their souls rest in peace...

Today, the 30th October reminds us of the deadliest terrorist attack in the history of Assam. A couple of serial blasts within few hours rocked various parts of the state with Guwahati, the heart of North-East the worst sufferer. More than 100 people were killed and thousand injured in the blasts. Guwahati probably does not live with the same spirit as Bombay lives and I am pretty sure the memories of last year are still haunting the Guwahatians. While talking to friends, relatives staying in the city I feel it, they are scared to go out for classes, office etc as if the same thing gonna happen today which happened one year back. As usual, the local media is also making too much hype putting all those terrible blast pictures on the front pages of news papers. Anyway life is not all about getting scared thinking what happened in the past, people need to move on looking towards a better future. Let's pray for all those innocent victims, may their souls rest in peace.

Saturday, October 24, 2009

Do we need "Bombay to Mumbai" type conversions every year?

It has become so common nowadays to see changes in the name of cities, streets as well as states in India. Every time I see the news "Union Cabinet has approved the change in nomenclature from xyz to abc", I find it so odd. People are so used to the earlier names that such a sudden change brings real chaos. Someone says correctly that everything was done by the British, we just keep changing the names. I agree that, some regional sentiments are attached to such changes. The names given by the British to the cities, states may not sound like the way it should be according to the language specific to that state. But why no one was there to think about it before? Its more than sixty years now since India got independence and now people are becoming desperate to change everything. They don't even realize how long it will take for the new name they give to become familiar to the world. For example if you change the name of a fifty year old institute like IIT Bombay to IIT Mumbai just because some political parties change the name of the city from Bombay to Mumbai, people would find it very difficult (specially abroad) whether these two names correspond to the same institute or not and that will surely gonna affect the academic part. But no matter what happens to the institute reputation and popularity, political parties will change the name for sure sooner or later. Today I have seen "Orissa is now Odisha, Oriya becomes Odiya" in Times of India which is just a replica of Bombay->Mumbai, Bangalore->Bangaluru and many others. I remember people in my state were also proposing the change of the name from "Assam" to "Asom". I am however not in favor of it. Basically the true ethnic pronounciation is neither Assam nor Asom. It is just a convenient way to write since there are some letters in Assamese alphabet which are pronounced in such a way that there is no counterpart in English or in Hindi. People write those alphabets either by using "s" or "h" in English. Thus although change in such nomenclature may have some correctness in the case of other states, this is not the case with "Assam->Asom". May be we should better stick to the earlier and most popular name of our state. Personally I feel, its the people of the state who have to carry the true identity of the state they belong to and their ethnic culture, not the name of the state.

Thursday, October 22, 2009

Coupling Constant Unification

Currently I am working on gauge coupling unification in certain specific models. I studied basic renormalization in abelian gauge theory as well as scalar field theory during my MSc coursework but did not study renormalization group evolution properly. My supervisor advised me to look at Weinberg's QFT volumes, and believe me I liked the way this renormalization topic is written in that book and that has probably given me enough enthu to spend 3500 bucks to buy all the three volumes. The renormalization group evolution is given by $ \mu (d g/d \mu) = \beta(g) $, where g is the coupling constant and $ \mu $ is the mass scale. Thus this equation basically predicts the evolution of the gauge coupling constant with energy scale. I have not yet looked into the derivations of the beta functions for the most general case. I am just using the standard formula for one-loop beta function from text books and using it in my own model. The new thing I have learnt is that choosing a specific gauge group does not decide the beta function completely. Its the particle content of that group: the fermions, gauge bosons as well as Higgs scalars which decide the form of beta function. Thus for the same gauge group if we modify the particle content, the beta function will also change and accordingly the evolution of the coupling constants.

String Theory Video Lecture Part 5

Yesterday we had the video screening of String Theory Lecture part 5 by Prof Shiraz Minwalla. It was longer than the previous ones as well as harder to follow. He was doing Path Integrals and Conformal Field Theory most of the time, both of which I have not learned yet in a systematic way. He is referring to the chapter on CFT in Polchincki's book. I really need to go through it before attending the next video. It is not possible to sleep also during the video lecture since not more than five people come for it...:P Hence there is no other way than listening carefully to what Prof Minwalla says.

Wednesday, October 21, 2009

An Unbelievable/Uncomfortable/Inconvenient Truth

Yesterday I came to know about an article related to P. Sainath, the 2007 winner of Magsaysay Award for journalism, literature, and creative communication arts and his studies as well as various published articles on Indian Poverty. The article titled "Uncomfortable Truth: P. Sainath reminds us that India is still a poor country" was published more than one year ago. The link to the same is here ( It is billion times more shocking than "An Inconvenient Truth", the documentary film on global warming. Nowadays due to media coverage as well as increase in public awareness, global warming has become the topic of discussion everywhere and people at least know what it is. But this "Uncomfortable Truth" about Indian poverty will probably give a shock to people from all over the world. Specially at a time when Indian economy is considered as one of the fastest growing economy and people projecting Indian economy as one of the most dominant one in coming years, people can hardly imagine that more than seventy percent of the Indian population is below the so called poverty line. However the Government report says a different story ( It is difficult to say which one is true. But an extensive study made by a person like P. Sainath can not be ignored at all. I do not know how the Indian Government will react to it. But if it is true, it will surely show how fragile Indian economy is. After all, an economy which is surviving on just one fourth of the population can not be a stable economy although for a certain period it may show significant growth. I have just come to know that P. Sainath is coming to IIT Bombay sometime in November. I hope he will make the things clear to us.

Monday, October 19, 2009

China leaves no stone unturned to keep India worried all the time..

From Kashmir to Arunachal Pradesh, from fake medicines with "Made in India" tag to Extremists in North East, it seems China is very much interested in keeping India worried. After declaring Sikkim as a part of India, China has directed its attention towards Kashmir and North East, the two most unstable regions of India hit by insurgency problem and many others. Needless to mention that China claims several thousands square kilometers of Arunachal Pradesh as its own territory. Having objected to Dalai Lama's proposed visit to Tawang in November, China even raised protest after the Indian PM visited Arunachal. It is also believed for a long time that the militants in the North Eastern states of India who are fighting for so called "sovereignty" get arms as well as shelter in China. According to media report China is also planning to construct a dam in Tibet which will severely affect the flow of the river Brahmaputra in Assam. It has also been reported that China is involved in various civilian projects (and may be military also) in the Pakistan occupied Kashmir (PoK) region, which India considers as illegally occupied by Pakistan. Apart from issuing separate visa to Indian nationals who are from Kashmir, China is now projecting Kashmir as a separate country. The handouts given to invited journalists in Tibet by the Chinese Government says "Tibet borders with India, Nepal, Myanmar and Kashmir". What the hell does it mean? Leave these political issues aside. China is doing more than that. Few months back I have seen in the news that China is exporting fake medicines with "Made in India" tag to African countries. What China wants after all? They would have probably invaded India again like they did in 1962 if India had not developed nukes by now. I hope India will act strongly against all these in a diplomatic way. China may be the fastest growing economy in the world, it may have the largest military strength, but that does not mean they will keep doing whatever they want. I was surprised to see the US president cancelling his meeting with Dalai Lama(during His visit to the US) just to keep the Chinese happy before his visit to China. Anyway I know too little politics to comment more on such issues. Its better to get back to physics...:)

Sunday, October 18, 2009

Hitler and IIT attendence...a must watch video..:D

Yesterday one of my friend suggested me to watch this video. This video is originally taken from the movie 'Downfall(Der Untergang)'. But a few clever IIT ians have changed the subtitles in such way that after watching this video people (who don't understant German of course) won't believe that it's fake. Have a look:

Purpose of Blogging

Sometimes I wonder why I am spending my time on the blogosphere. I keep writing random stuffs through which I don't have to carry any information to anyone. And I don't even think whatever I write here may prove to be useful for someone. But personally I was benefited a lot by several blogs. Those sincere bloggers are really doing a great job by sharing their ideas, opinions related to diverse fields. Specially the physics stuffs they write are very recent as well as significant. Whereas I use my blog as an open diary. I just write whatever I learn, whatever I do and all. I don't even know if they are worth writing, but it seems from a couple of months it has become one of my hobbies. I hope after spending another two-three years on the blogosphere I would be able to write some constructive things based on my own ideas.

Beer with Nair

After he got his "awesome-max" job few months back, he has sponsored beer party twice so far for us (his classmates who have not yet got their degree..:(.. ). Yesterday we had the occasion once again for such a beer party. After his first come back from the US, we had the first one where we had some Mexican beer called Corona. I never heard of it before, but believe me, it does not suck at all like Indian beers. It was really awesome. Yesterday I don't remember which beer we had, but it was not bad. Since I drink very rarely nowadays, yesterday I could not drink more than say 600 ml. It seems my capacity has fallen down a lot, not bad huh? Actually nowadays very few such occasions come and without any occasion I do not prefer to drink at all. I hope the next occasion will come again when Nair will come back from the US after six weeks. Thanks a lot Nair, keep sponsoring beer party every time you come home from abroad.

Friday, October 16, 2009

"What is more important is Science, not the country of origin of a scientist"...This is what Chemistry 09 Nobel Winner has to say!!

I saw a Times of India article today titled "A little less nationalistic hero worship, please" ( by 2009 Chemistry Nobel winner (with two others) Prof Venkatraman Ramakrishnan. It was quite natural for the billion Indians to cheer for him after he got the prize. But what he wants from us is to appreciate science more than nationalistic worship. Well, from my point of view he is correct. In the age of globalisation we after all have to work together to make earth a better place to live in rather than confining within the country barriers. However, I don't think Indians overreacted when he got the prize. Looking at the fact that there are very few Nobel laureates from this country which however has given birth to many great scientists as great as Nobel Laureates, people became naturally overwhelmed with joy. As mentioned in the article, many Indians were offended when Prof Ramakrishnan said "nationality being an accident of birth", and that's why he has come up with this TOI article to apologise as well as to convey a very important message why appreciating science is more important. Some of his lines as quoted from the article are ....
"...The best way to take pleasure in someone’s achievement is to take an interest in their work and feel motivated to learn more about science. I remember reading about Gellman’s work as an undergraduate in Baroda, and, when he won the Nobel prize, rushing upstairs to tell my parents. It did not matter to me whether he was Indian or not. In my case, I am lucky to have had a combination of education, opportunities and a great team of co-workers to have made a contribution to an important problem. I am not personally that important. If I hadn’t existed, this work would still have been done. It is the work that is important, and that should be what excites people....."
It is after all his capability to come out of country barriers and work for the human being as a whole which makes him so special. Think Global..Act Global...:)

Thursday, October 15, 2009

SERC XXV Main School in Theoretical High Energy Physics

The official announcement for the 25th SERC (Science and Engineering Research Council) school in theoretical high energy physics to be held in Punjab University, Chandigarh, India from 2-22nd April, 2010 came almost one month before. However the official poster for advertisement came two days back. The courses this year seems interesting like those of the previous school. Usually what happens is that people don't attend two consecutive SERC main school since the topics are totally different in two consecutive schools. But to my surprise, this SERC school topics are not too much unrelated to those covered in the previous one. In the previous main school we had basic string theory course and in the coming one there is a course on AdS-CFT and hydrodynamics. Similarly we had cosmology and particle physics course in the previous school and there is a course on GUT and leptogenesis in the coming one. So it is very difficult to resist from applying for the coming school as it appears (to me at least) that the topics covered in the previous school may come out to be of much help while attending the coming school. The poster for the school containing the details is below(click the image to get a better view):
After attending string theory lectures by Prof Sunil Mukhi in the previous SERC school, I am really looking forward this time to attend the AdS-CFT lectures by another big shot in string theory, Prof Shiraz Minwalla. The course on GUT, leptogenesis will be an another attraction of this school since the lecturer is Goran Senjanovic from ICTP, Trieste and the tutor is Borut Bajc. These names are very familiar to me for a long time since I have been reading couple of papers written by Goran, Borut, Aulakh et al. It will be a great privilege for me to meet these three big shots in High Energy Phenomenology at the same time. I just hope I will get selected to participate in the school.

FERMI does not confirm the rise in positron fraction with energy...:(

Today I saw a paper by W. de Boer titled "Indirect Dark Matter Searches in the Light of ATIC, FERMI, EGRET and PAMELA" ( It is related to the Invited talk at SUSY09, the 17th International Conference on Supersymmetry and the Unification of Fundamental Interactions, Boston, 2009. The author gives a good comparison between the results from various experiments related to cosmic ray positron excess. I must say after looking at the FERMI results in this paper I am not that much enthusiastic about working on the dark matter interpretation of positron excess as I was when I first saw PAMELA results. The basic difference between latest FERMI data is that it does not confirm the peak in positron fraction at several hundreds GeV. The FERMI spectrum is more or less flat. The plot shown in the paper is as follows
The author has mentioned all the attempts so far for the positron excess explanation and commented that all the explanations seem correct and nobody can rule out any one of them. He has considered contribution of all such effects in the paper. I was particularly interested in dark matter interpretation of this excess which was quite interesting as well as challenging, since you need to make your particle physics model such that the proposed dark matter candidate unlike neutralinos annihilate primarily into leptons and not hadrons. Anyway as the author says we should wait for the future FERMI data which might focus more on possible dark matter link.

String Theory Video Lecture Part 4

Yesterday we had the 4th weekly session of watching the string theory video lecture by Prof Shiraz Minwalla. Unfortunately the seminar room was occupied by some people and we had to move to an another room where I could not not configure my laptop with the projector and after trying for more than half an hour we decided to watch the video in the laptop only. In this part of his lecture he talked about tachyonic states in bosonic string theory and showed how 26 space-time dimensions appear naturally for the consistency of the theory. But the ground state of the theory still remains tachyonic. The first excited becomes massless for D=26. Since the 1st excited state behaves like a vector which has D-2 components and hence transform under SO(D-2) it can not be massive which transform under SO(D-1). I was wondering if we fix N=1 (1st excited state) in the the relation $$ m^2 = \frac{2}{\alpha}[ 2N-(D-2)/12] $$ and requiring this state to be massless, arrive at D=26 how would the same value of D would make the second excited state massless. Then Prof Ramadevi cleared my doubt saying that the higher excited states are Higher dimensional representation of SO(D-2) and hence need not be massless. Then he talked about $$ N= \tilde{N} = 1 $$ where the tilde means the right moving ( in case of closed string we have both left and right moving fourier modes). This corresponds to $ 24 \times 24 $ representation of SO(24) which will give rise to a massless symmetric tensor field $G_{\mu \nu}$, a massless antisymmetric tensor field $B_{\mu \nu}$ and a scalar field $ \Phi$ called the dilaton. Thus gravity comes out automatically in closed string theory. After that he gave a brief introduction to path integrals which he will probably use in his next lecture.

Tuesday, October 13, 2009

Its surprising to see more voter turnout in Arunachal than Maharashtra..:)

What a surprise! Almost 72% voter turnout was recorded in Arunachal Pradesh whereas only 60% in Maharashtra during today's Assembly elections. In a state like Arunachal Pradesh where there is hardly any kind of development, or which hardly get any kind of central government attention, people seem to have more faith in the political system than a state like Maharashtra, the capital of which is also the financial capital of the whole country. As a resident of the neighbouring state Assam, I always feel that North-Eastern states like Arunachal Pradesh are completely neglected by the Central Government in terms of infrastructure,transport, education, Industry and many others. It is needless to say that Arunachal has much better potential in terms of natural resources and tourism compared to most of the states in India. People become serious about Arunachal only when China says something related to Arunachal. It is quite well known that China claims several thousand square kilometers in Arunachal to be a part of its own territory which India always keeps denying. But instead of this cold war with China over Arunachal, I believe the Government should work more for the development of this state. Specially looking at such an impressive voter turnout which reflects the fact that people have faith in the great Indian Democracy there is absolutely no reason not to work for a better Arunachal.

Dark Matter and Black Hole!!

A few days back, I was having an interesting discussion with one of my friend in a public forum known as Actaphysica . He seemed to be an expert in Black Hole physics who opened various threads related to some interesting aspects related to black holes, hawking radiation(HR) as well as dark matter. He talked about the possibility of a black hole formed out of two unstable micro black holes. As we know the black body temperature associated with a black hole in inversely proportional to the mass squared. Thus smaller the mass is , higher is the temperature and sooner the black hole will evaporate. I had a doubt while discussing the possibility of an atom formed out of a black hole with charge -1 and mass $m_e$ which we call and eBH (electron black hole) and another with charge +1 and mass $m_p$ which we call a pBH (proton black hole). I raised the doubt saying that eBH being tiny will evaporate soon by emitting HR and hence there won't be any bound state forming between eBH and pBH. But my friend pointed out that only isolated black holes can radiate HR and finally evaporate. Thus within a bound state eBH and pBH won't be emitting HR. However if the radius of their bound state is smaller than the corresponding Schwarzchild Radius then the bound state itself can behave like a black hole and hence emit HR since the bound state is an isolated state by itself. This would be , according to him, a ground breaking result since so far people have no idea about internal substructure of black holes. One more interesting aspect of such bound state could be the relation with dark matter. If the bound state does not become a black hole then it would be a stable entity and hence can be studied from dark matter point of view. I do not know how much work is done in this direction but it seems like an interesting field to explore.

A purely supersymmetric origin of neutrino mass

Yesterday I came to know about a completely supersymmetric(SUSY) origin of tiny neutrino mass, that is, in the non-SUSY version of the model neutrino mass remains either zero or comparable to lepton/quark masses. This comes when neutrino mixes with the neutralinos in the Supersymmetric model. The neutralinos are the mass eigenstates of neutral gauginos as well as Higgsinos. Neutrinos can mix with the neutralinos only if the sneutrino field get a vacuum expectation value (vev). Diagonalizing the mixing mass matrix will give rise to a small neutrino mass by sutable adjustment of different scales. However since neutrino/sneutrino carry a lepton number whereas neutralinos do not, such mixing violate R-parity. This R-parity violation however should not lead to dangerous proton decay, but it will make the standard neutralinos decay into neutrinos. If neutralino is to be a dark matter candidate, the relic abundance will put a constraint on the R-parity violation. Thus this scenario will be tightly constrained by smallness of neutrino mass as well as dark matter relic abundance. I am trying to see if there is any other advantage of this approach, say from the point of view of recent positron excess measured by various dark matter indirect detection probes.

Quantum Foundation Lecture 3 cancelled without any email notifications...

It was really embarrassing yesterday when I was sitting in the P C Saxena Auditorium for almost 20 minutes along with 6-7 other students hoping that sooner or later the lecture will happen. But I finally gave up and went to the physics department which is ten minutes walk from the auditorium. There I saw a small notice saying that the lecture has been canceled due to health problem of Prof Roy. But there could have been a better way to communicate the message. In fact, the people who used to make the video recording of the lectures also came to the auditorium and preparing for the recording when I left the place. I have no idea how long they as well as the other 6-7 students were waiting there. At least the message could have been put in the auditorium notice board. I don't think I will be enthusiastic enough to attend the remaining lectures. May be it is better to look at the lecture slides which will be put in the department website after the lecture ends.

Friday, October 9, 2009

Quantum Foundation Lecture part 2

Today's lecture was more like a question answer session. It was natural that students will come up with many doubts after yesterday's overdose..:P. Most of the time Prof Roy had to answer very basic doubts raised by the students. He started with two comments regarding yesterday's class: Bell's inequality is fully relativistic and violation of local reality by Quantum Mechanics does not mean that information can carried from one place to another with speed more than the speed of light in vacuum. Then he gave an introduction to density matrix for pure and mixed states. Then he talked about separable pure states. These states are basically non-entangled and obeys local reality, Bell's inequality. He then talked about N-particle correlation function and how difficult it is to find out whether the N particle states are entangled or not. Since violation of local reality grows exponentially with number of particles and so does entanglement, hence it can speed-up quantum computation very efficiently. He skipped the latter half of the lecture since he ran out of time answering the doubts of the students and will probably talk about that in the next lecture which is on 12th October.

Wake Up Sid

Yesterday I watched the movie called "Wake Up Sid" released recently starring Ranbeer Kapoor and Konkona Sen Sharma. Well, I won't say it is a good movie, but an average one. The story was all about Sid, son of a famous industrialist in Bombay and Ayesha, a struggling, hard-working young lady who has come from Calcutta to Bombay in search of work. When they first met, they were just on two opposite poles. Sid was very childish, immatured whereas Ayesha was well focused on her dream of getting established in Bombay. The story basically shows the transition of Sid from a stupid boy into a self-established hard working man. It has a happy ending where Sid becomes quite matured, hard-working and independent young man to make himself upto Ayesha's mark and live together. As it is obvious by now, the story has not much depth as we expect in a movie starring Konkona. I have no idea if I would have even bothered to write about the movie if Konkona were not there...:P. But I would obviously rate this movie thousand times better than movies like KANK, another Karan Johar film. The movie reminded me of a news which I saw in Times of India few days back which said Karan Johar had to apologise for using the word "Bombay" instead of "Mumbai" in this movie. I don't see what is wrong in it, after all so many people are still used to Bombay instead of Mumbai, Victoria Terminus instead of Chattrapati Shivaji Terminus etc and Karan might have just picked up two such real persons in his movie.

Thursday, October 8, 2009

Quantum Foundation Lecture part 1

Today I have attended the first part of the lecture series I mentioned in one of my previous posts. Prof Roy covered lots of things in his very first lecture which might have made the junior undergraduate students feel slightly demotivated. This is obvious because the students who have not yet learned basic quantum mechanics properly, how will they appreciate the inadequacies as well as inconsistencies in quantum mechanics which have led to extension of quantum mechanics. At the end of the lecture the Head of the Physics department had to request Prof Roy to teach at slightly lower level from tomorrow looking at the fact that there are many junior students who are attending the lectures.
Anyway being a senior graduate student, I even could not follow the latter half of the lecture. He started with the theoretical inadequacies in quantum mechanics in spite of tremendous success experimentally and tried to motivate why we need a richer theory. He then mentioned Schrodinger's Cat experiment, Double Slit experiment, Wheeler's delayed choice double slit experiment, EPR Paradox, the concept of local reality and Bell's inequality. Then he showed how quantum mechanics does not obey this inequality. Although the qualitative part was very clear, the rigorous mathematical steps to derive the inequality was too much within an hour and in the very first lecture I believe. I hope he will repeat some of the things which he did today in tomorrow's lecture and will make the ideas, motivations very clear instead of spending much time on the mathematical derivations. Since most of the people are not familiar to this field at all, so they should get the motivations first to do it rather than start with the mathematics. Hope to see as many people as there were today. It could have been better to arrange some coffee and cookies to attract more people. Hope SAPD will do that in future lecture series....:)

Congratulations Prof Venkatraman Ramakrishnan...:)

This is the first time I guess, a scientist of Indian origin has got the prestigious Nobel Prize in Chemistry . It's a great privilege to offer Prof Venkatraman Ramakrishnan heartiest congratulations. Although officially he is an American citizen, people back in India are overwhelmed with joy and excitement. Prof Ramakrishnan who did his B.Sc from Baroda University, India and PhD from Ohio University, United States has made the billion Indians proud as well as inspired. Wish you all the luck and a long life. Keep inspiring us again and again!!

Wednesday, October 7, 2009

Video Lecture Part 2 and 3

Today we had the video screening of Prof Shiraz Minwalla's String Theory Lecture Part 3 in the Physics Department. Naturally the number of people coming for the lectures has decreased a lot compared to the lecture part 1. In part 2 he talked about Weyl transformations $$ {g}_{\alpha \beta} \rightarrow e^{\phi} g_{\alpha \beta} $$ as well as reparameterization invariance and how we can use them to remove one degree of freedom from the world-sheet metric and write it as $ g_{\alpha \beta} = \eta_{\alpha \beta} $ where $ \eta $ is the Minkowski metric. Then he showed how to write the action in light-cone world sheet coordinates. Then he used the constraints as well as reparameterization invariance in the light-cone world sheet coordinates to remove two degrees of freedom which results in D-2 modes of oscillations.

Today's lecture (part 3) was a bit more technical : how to quantize the action. He started with the action
$ -\frac{1}{4 \pi \alpha} \int \surd{-g} g^{\alpha \beta} \partial_{\alpha} X^{\mu} \partial_{\beta} X_{\mu} $
and went ahead to quantize it. He did not follow the conventional approach which most of the string theory books follow: find the classical canonical momenta and quantize it by giving operator meaning to the various involved quantities. He used symplectic structure approach in which he wrote the action in terms of two-forms. That part was really confusing since he was writing and erasing so many things on the black board. He mentioned that this symplectic structure approach will be very useful while doing compactifications. He is basically strictly following the string theory book by Luest and Theisen, may be looking at that book will help to understand the things he did today in a better way.

Monday, October 5, 2009

A Dream Come True....:)

Finally I purchased all the three volumes of Steven Weinberg's Quantum Theory of Fields. I could do that a little later also since these books are available in the library and I have the e-copies also. But I was so much pissed off while reading those e-books that I could not stop myself from spending 3500 rupees to purchase those volumes. The worst thing about these QFT texts is that in almost every single page the author will be referring to some equation or some section in the other two volumes. I had a very hard time reading three e-books at a time. Sometimes I wonder why the author did not write a single book instead of three volumes. Its true that the book will become too heavy in that case but for me at least it will be less painful to read one book at a time than three different books. Now I have all the technical books written by Weinberg and I thought it would be great to take a group photo of them..:P

Sunday, October 4, 2009

Latest Assamese full length movie "MON JAI"

This time I went to Assam on the occasion of Durga Puja I came to know about a new Assamese movie titled "MON JAI". It is a real surprise for the people of Assam to see the release of full length Assamese movie. After a series of bomb blasts in the movie theaters across Assam few years back, the whole Assamese film industry headed for sure and certain collapse. More than half of the movie theaters had to shut down their business. And for their own survival the people involved in the film industry moved to drama as well as making of short musical VCD s etc. It was really unfortunate to see such a fate of this industry which started in 1935 with the first Assamese movie Joymati. However with the release of Mon Jai starring Zubeen Garg, Nishita Goswami, I am still hopeful of revival of the film industry. Although I did not have time to watch the whole movie, the first part I watched was really nice. The movie is a bit slow one but has been able to present beautifully the true picture of an Assamese well-educated, unemployed, frustrated youth played by Zubeen. Unemployment in Assam has always been a cause of many other problems and vice versa. Anyway I liked the role of Zubeen very much, he has improved a lot in his acting skills. The title track sung by him is really heart-touching, the youtube link of which is below:

Viva La Assamese Film Industry. I am hopeful of many more such releases in the coming years.

Saturday, October 3, 2009

Lecture Series on 8, 9,12 and 13th October 2009

The Student Association of Physics Department IIT Bombay is organizing a series of lectures by Prof S.M. Roy (Retired Professor, TIFR, ). The details of the lectures are as follows:

* Lecture 1 - October 8th, Thursday at 5 PM at KRESIT Auditorium:
- Quantum Foundations
- Einstein Locality / Local Reality
- Einstein-Podolsky-Rosen Paradox
- Bell Inequalities

* Lecture 2 - October 9th, Friday at 6:30 PM at KRESIT Auditorium
- Many particle Bell Inequalities
- Schrodinger Cat States
- Quantum Entanglement & Tests of Quantum Entanglement

* Lecture 3 - October 12th, Monday at 5 PM at P C Saxena Auditorium
- Applications of quantum entanglement:
- Quantum Communication (cryptography, dense coding, teleportation)

* Lecture 4 - October 13th, Tuesday at 5 PM at P C Saxena Auditorium
- Quantum Computation:
- Grover's search algorithm
- Super-Zeno algorithm to preserve quantum states

The interested people can register for these lectures here . Since very few people work on this area specially in India, I do hope this lecture series would generate lots of interest among people towards this field and will push for doing research related to one of the most fundamental aspects of modern physics.

So many bibliographical complaints...:(

Just after I submitted my first paper to arXiv, I am getting complaints from people regarding citations, references etc. As a new entrants to this arxiv, SPIRES world I am naturally surprised to see people care so much about whether a new paper somehow related to their earlier work cites their papers correctly or not. I am currently making a list of all these complaints and hopefully will fix it when I replace my paper in arXiv...:)

Friday, October 2, 2009

Finally put the paper on arXiv...:)

After a long wait and a series of corrections, modifications finally I submitted my paper to . One of my friend Sudhanwa Patra is a co-author of this paper. The arXiv link to the paper is . Hopefully we will soon send it to some journal most preferably PRD. The work is all about incorporating type III seesaw of generating small neutrino masses within a Supersymmetric Left-Right model framework. We have also discussed dark matter phenomenology in a qualitative way. Suggestions, comments and criticisms regarding the paper are most welcome.

Thursday, October 1, 2009

Durga Puja 2009 at Home after 4 years

After four long years, this year I could somehow manage to enjoy durga puja in my state Assam. Although it was my shortest home trip ever, yet it was really enjoyable may be because of the festive environment there. I went there on 24th September and came back on 29th September. Although there is no official holiday for Durga Puja in IIT Bombay, I missed only one class during this period. The weather in Assam was unusually hot during Puja, there was hardly any rainfall, but still I was so happy to be there that the weather had very little impact on my enjoyment. Although my family members were a bit upset when I left home without staying for two complete days, they did not say anything. My journey was cool this time since I did not take the stupid direct train from Mumbai to Guwahati which usually takes around sixty hours. I went there by Jet Airways and came back by Indigo. This was my third journey by domestic aircraft, I was very much surprised by the fact that even the top quality domestic airlines like Jet Airways do not provide any food (except a tiny drinking water bottle) without any extra charges. Indigo was even worse in the sense that they don't give water bottles for free. It seems next time I should not forget to bring my own watter bottle as well as some food each time I travel by a domestic aircraft.