Tuesday, March 5, 2024
Rahul Basu 04/03/1956-05/03/2011
Monday, January 22, 2024
Ram Mandir post
Sunday, December 17, 2023
IPA Rahul Basu Memorial Award 2022
Here is a short summary of the work for which the IPA Rahul Basu Memorial award for 2022 was given.
The awardees:
Dr. Anupam Ray, Tata Institute of Fundamental Research, Mumbai Thesis Title: Unravelling the Mystery of Dark Matter with Stars & Black Holes.
Dr. Anuparam Ray won the award for his important contributions to astroparticle physics. Anupam improved the formalism of dark matter capture in stars using multiple scattering techniques. He also studied the possibility that neutron stars could transmute into light black holes. One of the remarkable results he found was that asymmetric dark matter could accumulate inside neutron stars and transmute them into a low-mass black hole. These transmuted black holes could be lighter than allowed by the naive Chandrasekhar limit, and could find relevance for the unusual mass-gap objects being seen by LIGO. Another interesting direction in his work was the calculation of neutrino based constraints on the abundance of light primordial black holes.
Dr. Shubham Pandey, Indian Institute of Science Education and research Pune
Thesis title: Performance of High Granularity Calorimeter prototypes for the CMS HL-LHC upgrade in beam test experiments at CERN.
Dr Shubham Pandey was a part of the efforts towards preparations for beam test experiments and data taking at CERN for high luminosity LHC operations.
He provided the first set of calibrations of calorimeters using muons in the beam test experiments, which led to alignment corrections and signal to noise studies. His analysis of pion data led to an algorithm which performed well across the full energy scale used in the experiment. His work superceded previous results and led to the identification of lacuna in calibration and resolved discrepancies in the scale, leading to improved final results. His thesis constitutes an important reference document for new analysers.
The runners up:
Dr. Biswajit Sahoo, Harish-Chandra Research Institute, Prayagraj. Thesis title: Classical and Quantum Subleading Soft Theorem in Four Spacetime Dimensions.
Dr Biswajit and collaborators gave a proof of the a multiple soft graviton theorem in a general theory of matter coupled to graviton fields. He also verified this for a special case. They further extended this to the quantum version of the soft graviton theorem, and found logarithmic corrections similar to those found earlier for the classical case. He also added the case of electromagnetic radiation. Here, these logarithmic corrections determine the late time tail of the gravitational radiation emitted during any scattering or explosion, and could be observed in future gravitational wave experiments. Further analysis of these corrections was carried out via classical analysis.
To summarise, Dr Biswajit's thesis contained very sophisticated technical analysis with consequences which can in principle be tested in the classical limits and in experiments.
Dr. Samir Banik, National Institute of Science Education and Research, Bhubaneswar
Thesis title: Search for Lightly Ionizing Particles in SuperCDMS and simulation of neutron
backgrounds.
Dr Samir Banik's work is a very important contribution towards detectors of very low energies where lightly ionising particles can exhibit fractional charge. The thesis developed suitable modules in GEANT4 which is a universal simulation tool for nuclear and particle physics.
The simulation work done here is to be integrated in the official GEANT4 toolkit in future.
This was a highly commendable contribution. In addition, the thesis set very strong limits for fractional charges. These results provide an important step towards search of light charged particles and design of dark matter detectors in India.
It was a great pleasure to listen to the awardees present their work, exactly one year ago at IISER Mohali.
The depth and breadth of the thesis nominated and awarded speaks for the high level at which research is carried out in Particle Physics in the country.
Grateful thanks to the award committee and others who did the gruelling work of reading the 20+ nominations and narrowing them to 4, and also to the Indian Physics Association for administering this award.
This (much delayed) blog post is by Neelima Gupte and Sumathi Rao.
Wednesday, August 23, 2023
Chandrayaan 3 lands on the moon
Chandrayaan 3 made a successful soft landing on the moon. India now joins the elite group of four countries which has managed to do this, the earlier three being the United States, Russia and China.
Also happy Madras week. Now that we have landed on the moon, maybe Chennai corporation can acquire from Isro the technology required to fix the lunar surface on the roads of Velachery (our local suburb).
This post by Neelima Gupte and Sumathi Rao
https://twitter.com/isro/status/1694376945340080398?s=20 https://twitter.com/isro/status/1694376945340080398?s=20https://twithttps://twihttps://twitter.com/isro/status/1694376945340080398?s=20The first few picturestter.com/isro/statushttps://twitter.com/isro/status/1https://twitter.com/isro/status/1694376945340080398/photo/1694376945340080398/photo/1/1694376945340080398?s=20ter.com/isro/status/1694376945340080398?s=20
Sunday, March 5, 2023
Rahul Basu 04/03/1956-05/03/2011
The Good
The good are vulnerable
As any bird in flight,
They do not think of safety,
Are blind to possible extinction
And when most vulnerable
Are most themselves.
The good are real as the sun,
Are best perceived through clouds
Of casual corruption
That cannot kill the luminous sufficiency
That shines on city, sea and wilderness,
Fastidiously revealing
One man to another,
Who yet will not accept
Responsibilities of light.
The good incline to praise,
To have the knack of seeing that
The best is not destroyed
Although forever threatened.
Robert Burns.
This post is by Sumathi Rao and Neelima Gupte.
Sunday, November 27, 2022
The IPA Rahul Basu Memorial Award 2022
It is our great pleasure to declare that the winners of the IPA Rahul Basu Memorial Award have been selected for the period 2020- 2022. These are:
Winners:
Dr. Anupam Ray, Tata Institute of Fundamental Research, Mumbai Thesis Title: Unravelling the Mystery of Dark Matter with Stars & Black Holes.
Dr. Shubham Pandey, Indian Institute of Science Education and
research Pune
Thesis title: Performance of High Granularity Calorimeter
prototypes for the CMS HL-LHC upgrade in beam test experiments
at CERN.
Runners up:
Dr. Biswajit Sahoo, Harish-Chandra Research Institute, Prayagraj
Thesis title: Classical and Quantum Subleading Soft Theorem in
Four Spacetime Dimensions
.
Dr. Samir Banik, National Institute of Science Education and
Research, Bhubaneswar
Thesis title: Search for Lightly Ionizing Particles in SuperCDMS
and simulation of neutron backgrounds.
The award ceremony will be held as a part of the DAE symposium on High Energy Physics, 12th – 16th December 2022 at the Indian Institute of Science Education and Research Mohali. The winners will be given a cash prize of Rs.25,000/- each and a citation. The runners up will be presented a citation.
Sunday, October 9, 2022
The Nobel Prize in Physics 2022
The Nobel Prize in Physics has gone this time to Klauser, Aspect and Zeligman, for their pioneering experiments which proved the existence of the quantum phenomenon that has come to be called entanglement, by which the wave function of a system can carry simultaneous information about two particles which could be widely separated in space. This notion, which is the signature notion of quantum mechanics is at variance with the notion of locality, which lies at the heart of classical physics. Hidden variable theories were proposed by David Bohm, by which the wave function could incorporate a 'hidden variable' which could encode the additional information, and thus make the wavefunction compatible with locality. However, Bell showed, in a series of papers that quantum mechanical wave functions, and wave functions which incorporate hidden variables, had differing levels for correlations for which bounds could be quantified. This led the way to experiments where the predictions of the theories could be verified.
Klauser, a really young man those days, put his career on line and devised ingenious experiments from bits and pieces he found lying around in the lab and set up an experiment which measured the polarisations of two photon states where the photons travelled in opposite directions. Unlike what he hoped, the measurements supported the predictions of quantum mechanics. Aspect and Zeligman in later years added further refinements via very sophisticated experiments which incorporated random elements and very large separations into the experiments. Alas, the photons remained stubbornly correlated, i.e. entangled at levels predicted by quantum mechanics, and notions of locality could not be rescued via hidden variable theories.
It is not quite correct to say that these experiments opened the way to current applications ranging from quantum algorithms to quantum computers which rest on entanglement. Entanglement is anyway central to quantum mechanics. However they are extremely important from the point of view of the foundations of quantum mechanics, and notions of locality, measurement and simultaneity which are crucial ingredients of the theory. It is wonderful that theories and experiments which were considered career breakers for physicists have been honoured with the Nobel prize. Salutations to the stubborn physicists!
This blog post is by Neelima Gupte and Sumathi Rao.
More technical references here.