Monday, February 2, 2015

Dust in our eyes?

It appears that the latest Planck satellite data is conducive to the conclusion that the discovery of gravitational waves claimed by the BICEP2 collaboration last year, is not yet one to get starry eyed about. The latest data which measures the concentration of dust in the region where the BICEP2 measurements are carried out indicates that the quantum of dust is sufficiently large that it could be responsible for about half the B-wave polarisation observed in the BICEP2 signal. This has led to wide-spread disavowal of the BICEP2 results, and caused some dismay in circles that have been heartened by their support for inflationary scenarios. Those that went overboard in the opposite direction even said `Big Bang theory disproved' ! (The Times of India should really get some proper science reporters).

However, these reports of the demise of the theory are also highly premature (as in the case of Mark Twain!). The European Space Agency, which manages the Planck satellite,  puts it more soberly, “Despite earlier reports of a possible detection, a joint analysis of data from ESA’s Planck satellite and the ground-based BICEP2 and Keck Array experiments has found no conclusive evidence of primordial gravitational waves”.

 This null result does not disprove the existence of gravitational waves, nor does it rule out inflation. It merely indicates that BICEP2 has not detected gravitational waves yet, with a high degree of certainty. The gravitational wave signal may still exist in the observed BICEP2 data, but may be obscured by the noise, so this new result can place an upper limit on the possible strength of the B-mode polarisation caused by gravitational waves. The search for gravitational waves still continues, and we look forward to more conclusively established results in the near future.

This blog post is by Neelima Gupte and Sumathi Rao.

BTW: Speaking of science reporting, this is a good place to draw attention to the  IIT Madras science magazine brought out completely by IITM students on some of the research done at IIT Madras, including research on inflationary scenarios carried out at the Physics Department. Do have a look.

Friday, December 26, 2014

The IPA Rahul Basu Memorial Award

The IPA Rahul Basu Memorial Award  (2014) for the best thesis in High Energy Physics was presented on 12th December, 2014, at the DAE Symposium held at IIT Guwahati. As mentioned in one of the earlier posts, the two awardees for the 2012-2014 period were Dr. Pratishruti Saha (Univ. of Delhi) for her thesis entitled `Addressing some issues beyond the standard model at Hadron Colliders', and Dr.  Nikhil Karthik (TIFR, Mumbai) for his thesis entitled `Studies on gauge link smearing and their applications to lattice QCD at finite temperature', and two  honourable mentions, Dr.  Ritu Aggarwal (Panjab University) for her thesis entitled `Measurement of High x neutral current ep cross sections and extraction of xF3 structure function using Zeus detector at Hera', and Dr.  Amaresh Jaiswal (TIFR, Mumbai) for his thesis entitled `Formulation of relativistic dissipative fluid dynamics and its applications in heavy-ion collisions'.  The two awardees gave talks on their work during the award ceremony, Dr. Saha, in person, and Dr. Karthik via a Skype connection.

Dr. Saha explained how her work on  direct and indirect searches at various accelerators could be used to identify new physics.  A very well cited paper of her's identifies  how measurements at the Tevatron and the LHC could be used to distinguish between various scenarios which go beyond the Standard Model. Dr. Saha and co-workers had  considered how top polarisation could be used to distinguish between various scenarios, which had been used to explain asymmetries in the top quark production process. The work also had relevance to observations at the Large Hadron Collider.  Her thesis focused on the fact that the top quark occupies a special place in the standard model, and hence, the analysis of its behaviour can have important implications in scenarios which attempt to go beyond the Standard model, in various sectors like the Higgs sector.  She had also analysed the behaviour of the bottom quark and its contribution to resonances.

Dr. Nikhil Karthik spoke about the work in his thesis, which contributes to important technical advances in  lattice QCD, and also studies its deconfined phase. Although the coupling constant in this  phase is not too large, perturbative estimates of quantities like the viscosity and the screening mass do not agree with expectations due to discretization effects. Specifically, existing lattice studies based on the staggered discretization of quarks, found a screening mass which, contrary to expectations is smaller than that of the free field theory. Smoothed gauge configurations are the prescription to ameliorate such unwanted discretization effects. Dr. Karthik's thesis investigated the effects of different types of smoothing, and devised an optimum smoothing strategy which succeeded in   identifying the reasons why the screening mass shows the observed behaviour.  Dr. Karthik's talk was also notable due to the clarity with which technical issues were conveyed to the audience.

The award ceremony was well attended, with many students and many well known physicists in the audience. It was heartwarming that three of these were  Rahul's friends in graduate school,  Prof. Rohini Godbole, Prof. Ashoke Sen, and Prof. Sunil Mukhi, distinguished physicists, and in the case of Profs. Mukhi and Godbole, members of the award committee. We congratulate the winners, and wish them all success in their future endeavours.

This blog post is by Neelima  Gupte and Sumathi Rao. 

Wednesday, December 17, 2014

For the children

For the children of Peshawar

Rest in Peace.

This blog post by Neelima Gupte and Sumathi Rao.

Wednesday, November 26, 2014


But what about the unsung one?
The companion to the great hero,
does he not deserve praise?
Destiny may not have chosen him,
Fate must have overlooked him,
but he still fought the great evil,
slayed the vile demon.

Nothing can be done alone,
too often is this forgotten.
The focus is put on one,
who did not choose,
but was chosen.
What about the other,
the one that did choose?

He chose to risk everything.
There was nothing great at work,
forcing him to choose.
It was a simple,
yet immense, decision.

Sometimes the greater heros are not the destined ones,
they are the ones that stood by the heros,
by the choice they made,
never regretting it,
only pushing forward to the goal.
Never  overlook  the companions,
for something important will be missed,
that may be lost forever.

-James Anderson ,   'To the unsung hero'.

For  Tukaram Ombale and the other ordinary citizens of Mumbai who did far more than their duty on 26/11.

This blog post is by Neelima Gupte and Sumathi Rao.

Thursday, November 20, 2014

The IPA Rahul Basu Memorial Award (2014)

The winners of the Rahul Basu Memorial Award (2014) for the best thesis  in high energy physics have been announced.

The winners are

1. Pratishruti Saha (Univ. of Delhi) for her thesis entitled

Addressing some issues beyond the standard model at Hadron Colliders

2. Nikhil Karthik (TIFR Mumbai) for his thesis entitled.

Studies on gauge link smearing and their applications to lattice QCD at finite temperature.

The following theses have received Honourable Mention

1. Ritu Aggarwal (Panjab University) for her thesis entitled

Measurement of High x neutral current ep cross sections and extraction of xF3 structure function using Zeus detector at Hera

2. Amaresh Jaiswal (TIFR, Mumbai) for his thesis entitled

Formulation of relativistic dissipative fluid dynamics and its applications in heavy-ion collisions

Congratulations to all winners. The awards will be presented at the next DAE Symposium on High-Energy Physics, being held in Guwahati from December 8-12, 2014. The award ceremony has been scheduled on December 12th from 4-5:30 PM. Dr. Saha and Dr. Karthik will present talks on their theses and receive a cash award, and Drs. Aggarwal and Jaiswal will be presented with citations.

The  Award committee members were Sunanda Bannerjee, Rohini Godbole, Sourendu Gupta, Neelima Gupte, Bedanga Mohanty, and Sunil Mukhi. The award is administered by the Indian Physics Association.

This blog post is by Neelima Gupte and Sumathi Rao.

A short report of the award ceremony can be found in the post on 26/12/2014.

Saturday, November 8, 2014

Who owns India?

After the idea of India has been debated endlessly for years, here comes a new debate: Who owns India? This provocative question was posed by Gopalkrishna Gandhi in his public lecture under the Indian Academy of Sciences auspices  at IIT Madras yesterday.

It appeared that the real question posed was not who owns India, but who thinks they own India. This question can have many answers, some of which were proposed by the speaker in his talk, using the north/south paradigm. These started with the geographic north of India  which has always imposed it's political hegemony on the south. While the presidentship of India has rested many times with those from the south, although C. Rajagopalachari, one the speaker's two distinguished grandfathers,  had to yield his claim to the first presidentship to Dr. Rajendra Prasad, the north's claims to the prime ministership, the executive headship of the nation,  have been consistent, with P. V. Narasimha Rao and K. Deve Gowda having been the two exceptions.  The other exception to the rule, has been Kamaraj's astute stewardship of the country during the crucial transitions after the sad demises of Nehru and Shastri, one after the other. The north has also always  been vocal about it's cultural presumptions and lack of knowledge about the south, especially that of the quite major distinctions between southern states. The south has been philosophical about these assumptions, which arise from the more basic assumption of ownership.

However, the geographic north and south are not the only north south divide! There's the techno-economic north and south divide as well. This north south divide exists both between nations and within nations, with the north's paternalistic assumption that the protection of it's own interests also contributes to the 'development' of  the south, being remarkable for its convenience, and for the justification of its actions. A similar divide also exists between genders. It is not even necessary to state which is north here!

The speaker ended with a specific request to the academies. It's necessary to know who owns India (the people of India, it is clear). It is also necessary to know what India owns. The huge resources of India are well documented, especially by the Surveys of India, starting from the Survey of India from 1757, to the Geological Survey of India  also started circa 1857, the Botanical and Zoological Surveys of India, and others.  It would be well if the scientific academies took advantage of this knowledge, to opine on how this wealth could be used to maximally benefit its owners, the people.  This  request was an eye-opener, and we hope it will chart a direction for our scientific bodies.

This blog post is by Neelima Gupte and Sumathi Rao.

Wednesday, September 24, 2014

MoM's made it to Mars

(A view from the ground. Curiosity Rover picture  (NASA via Scientific American))

First map of Mars,  Giovanni Schiaparelli,  (1888)
The Mangalyaan has safely made it to the Mars orbit, dead on time and with no glitches. We join the nation and PM Modi, (natty in a red Nehru jacket),  in congratulating the ISRO scientists on  success in a difficult mission. We take particular pride in the number of women we saw in the mission control room (on our TV screens, of course!). It was a good start to Wednesday morning, which has now become the Mangalvaar.

More soon, it is a working day after all. In any case ISRO has said it all on it's twitter page  here, an admirable job by their PR team, in publicising the sterling work done by their scientists.

This blog post by Neelima Gupte and Sumathi Rao.

First pic here.

One more.

Dust storm!

A 3-d picture.



Mountains and valleys.

The photo top left shows Elysium, the largest volcanic region of Mars, the bottom right shows the mountains and canyons, Mount Olympus, no less.

MoM's quite the chatterbox, and has lots of friends up there (Five orbiters, two rovers  and a flyby, hope we counted everyone).
They are not all as talkative!