Various thoughts and advertisements! Posts before 29 August 2026 are an archived copy of public Facebook posts. Comments? Email me.
Very privileged to have attended the Advanced Summer School on Quantum Physics organized by Scientists for Palestine. I learned a lot from the courageous and generous Palestinian students who attended the event despite everything that is happening. Many thanks to Scientists for Palestine for organizing this.
Please join us for an interaction between academics from India and Pakistan on Thursday evening. See below for details and Zoom link. This meeting is open to everyone.
๐๐ง๐๐ข๐-๐๐๐ค๐ข๐ฌ๐ญ๐๐ง ๐๐๐๐๐๐ฆ๐ข๐๐ฌ ๐๐ข๐๐ฅ๐จ๐ ๐ฎ๐
When nations are at war, nationalism dominates the narrative and exercising freedom of speech may be misconstrued as treason. In the prevailing atmosphere of jingoism and warmongering, how should academic scholars conduct themselves and advance the causes of peace and justice?
Join Zoom Meeting
https://us06web.zoom.us/j/86579487198?pwd=gvWIpW1FEE37StIbHKeYFDlamSH4f9.1
Date and day: 12 June, Thursday
Time: 7:30 pm, Pakistan time, 8 pm, India time
Chair: Prof. Pervez Hoodbhoy, Physics, Pakistan
Speakers: Mridula Mukherjee, History, India A.H. Nayyar, Physics, Pakistan Achin Vanaik, Political Science, International Relations, India Syed Jaffar Ahmed, Social Sciences, Pakistan Aditya Mukherjee, History, India Sadia Manzoor, Physics, Pakistan Radha Kumar, Peace and Conflict Resolution, India Riaz Ahmad, Chemistry, Pakistan Amit Singh, Mechanical Engineering, India Riaz Shaikh, Social Sciences, Pakistan
Moderator: Suvrat Raju, Physics, India
Academics for Democratic Rights (https://acdr.in/) and India Academic Freedom Network (https://www.indiaacademicfreedom.net/) are organizing a virtual discussion on the UGC Draft Regulations tomorrow: Sunday, 6 April at 3 pm.
The discussion will be led by Dr. Furqan Qamar, Dr. Sudhanshu Bhushan and Dr. P. K. Abdul Rahiman.
If you would like to attend, please register at this link: https://docs.google.com/forms/d/1QhY0ie3gjPyhIXw-SMUTsGJL9eqNIKX4uG6Bpi4WZ8c/edit
(Alternately scan the QR code in the poster below)
I am surprised at how rapidly elite U.S. Universities have crumbled under pressure from the Trump administration and are cracking down on pro-Palestinian activism.
Here is an email I sent to Harvard’s president today in response to an email sent by Harvard’s leadership to all alumni signalling that it is willing to appease the Trump administration.
A second point I find disturbing is that while some academics have been willing to raise the rather obvious concerns about academic freedom, very few are willing to make the other obvious point: the student protesters are taking a brave and morally correct stand by opposing Israel’s genocide in Gaza. The Trump administration is simply responding like other repressive regimes do: faced with criticism that it cannot address on the merits, it chooses to attack its critics by inventing false charges of anti-semitism.
In her budget speech earlier this month, the Finance Minister slipped in a seemingly unrelated remark: the government plans to amend the Indian nuclear liability act. This was deliberately timed so that the Prime Minister could point to this announcement in Washington, which he is visiting today. Nuclear liability might seem to be an arcane detail but this announcement should concern all of us.
Ever since the Indo-US nuclear deal, the U.S. has wanted India to buy nuclear reactors from American companies. However, there are two problems: (a) these reactors are extraordinarily expensive; the main American reactor on offer is the Westinghouse AP1000 and the last two constructed in America cost $36.8 billion. (b) American companies want a legal arrangement where they are completely indemnified from the consequences of an accident! (Similar comments apply to multinational companies from countries like France.)
In 2010-11, the UPA government created a law to appease the U.S. This law overrides the Indian “absolute liability” framework for hazardous enterprises. It channels any liability for an accident to the operator, which is an Indian public sector company and caps the liability at an absurdly small amount. However, due to pressure from civil society and the opposition, the UPA government was forced to include a clause called the “right of recourse”, which allows the operator (but not the victim) to sue the reactor manufacturer if the accident was caused by a design defect. The US has been furious about this clause ever since and, partly for this reason, its companies have been unable to sell in India.
This is an excellent outcome! It has saved us from several Enron-type deals: had India bought these reactors, we would have been paying for them for years, with this money lining the pockets of U.S. companies. The fact that no such reactor has been imported in almost two decades is a significant success of peoples movements that have pointed out their problems.
It now appears that the Modi government has announced its intention to bend the knee and amend the law to please Washington.
In today’s Hindu, Ramana and I wrote about the implications of this potential amendment and what it reveals about the government’s priorities. https://www.thehindu.com/opinion/lead/nuclear-energy-dangerous-concessions-on-liability/article69211997.ece
Lectures from my introductory QFT course last year: https://www.youtube.com/playlist?list=PL04QVxpjcnjhg3WHxG8sC1QHrpY_7dnoz
This is a fairly standard course that we offer at ICTS annually. I don’t think I said much that was new. We keep the Moodle open for anyone to join and view. A few months back, an unidentified person downloaded the lecture videos and uploaded them to Youtube – the same person also took them down a few weeks later. To my surprise, I heard from a number of students from other institutes who said they had found them useful. So we have now uploaded this ourselves.
New paper to end the year with Kristan and Antony. Last year, with Jonathan, Antony and Kristan studied quantum information measures for subregions in gravitational theories. Some of their results might appear puzzling if you have been following recent progress on the holography of information. In quantum gravity, information in a bounded subregion is available in its complement. This might suggest that it shouldn’t make sense to measure the information content of a bounded region in gravitational theories.
In today’s paper we reconcile these observations. One should think about the holographic properties of gravity like unitarity. Unitarity is important for precise nonperturbative questions about any system, and can be verified in perturbation theory about simple states, as we do in elementary QFT courses. But, in the presence of a macroscopic background, if we coarse grain our observables — as we do in everyday life — physics appears dissipative. Similarly, holography is important if we ask precise questions about information loss. And, for simple states, one can check perturbatively that gravity localizes information differently from quantum field theories. But, in the presence of a macroscopic observer with coarse-grained abilities, holography can be obscured and this allows one to define “algebras” for bounded regions and their complements and quantify their information content.
The observer needs to be heavier than the cosmological scale but lighter than the Planck scale. In our world, a virus on top of the vacuum would do: the mass of a virus is 10^(-15)g (see the biophysics paper in our refs ) — well above the cosmological scale (410^(-66) g) and well below the Planck scale (210^(-5)g).
Quasilocal observables about macroscopic backgrounds have been studied many times before. But it doesn’t seem to have been noted that, with some jiggling of notation, the formulas used to define these observables go over exactly into the formulas used to define the so-called “crossed product” in the literature on von Neumann algebras. This is not only true for the formulas in today’s paper. We went back and looked at a paper with Kyriakos from 2015, exploring the interior of an eternal black hole, and the crossed product had appeared secretly there as well!
P.S: Just to be clear and to anticipate possibe confusion: these techniques can’t be used to define a meaningful Page curve for black-hole evaporation. The unitarity of black-hole evaporation relies on nonperturbative effects and in this regime, these quasilocal constructions break down. It is an invitation to paradox to conflate everyday intuition about locality with intuition from unitarity, as both Hawking and Page did.
Of course, if one demands that the Page curve should be the answer then one can find the right question by adding nongravitational baths to AdS, or by dividing the boundary into two regions etc. but these curves don’t represent information “emerging” from the black hole; holography of information tells us the information never goes “in”, and so it doesn’t have to emerge.
See http://www.arxiv.org/pdf/2412.21185 for this discussion and more!
Last month, as part of Academics for Democratic Rights, we organized a talk by Sundos Hammad and Ahmad Sabobeh who are part of the Right to Education campaign at Birzeit University in Palestine. The talk was titled “Introduction to Scholasticide and Genocide”. Education is a means of empowerment and the speakers explained, powerfully and movingly, how Israel has violently disrupted educational systems in Palestine for decades. It is very important to hear directly from those who are living in Palestine under the occupation. I urge everyone who would like to understand the situation in Palestine to watch this recorded video. Please also share it with others.