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Nirmalya Kajuri

@kajunut.bsky.social
1.2K followers 120 following 443 posts

Assistant Professor of Physics at IIT Mandi and Science Writer. Writing a pop sci book about black hole information loss paradox.

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Nirmalya Kajuri @kajunut.bsky.social · 16h
I have a question about analog gravity/qft experiments: what do we learn from them about nature? The math of QFT in curved spacetime was never in any doubt, and that's the part these experiments test. Put different, a negative result won't lead us to conclude that we got QFT wrong. ⚛️
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Nirmalya Kajuri @kajunut.bsky.social · 01/10/2026
Had a good time at RQI-N. Nice to get an overview of where the field of relativistic quantum information is at. Got a few ideas for future projects too!
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Nirmalya Kajuri @kajunut.bsky.social · 29/09/2026
A sure sign of a stagnant field is that fashions come and go, leaving no trace. Healthy fields are not immune to fashion, but some of them do end up transforming the fields, and future developments build on top of them. 1/2 🧪
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Nirmalya Kajuri @kajunut.bsky.social · 28/09/2026
The fields of relativistic quantum information and theoretical high energy physics have some overlap, but somehow the communities do not talk to each other as much as one might expect. So it is nice to attend RQI-N 2026 at IISER Mohali and learn about what they are up to.
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Nirmalya Kajuri @kajunut.bsky.social · 28/09/2026
Years ago, Rafael was visiting RRI Bangalore. I was a PhD student at the time. I travelled from Chennai to Bangalore (5 hrs by train) to talk quantum gravity with him. When I met them, his wife Fatma greeted me with "Oh you are the guy who travelled all this way to meet Rafael!" 1/2 ⚛️
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Nirmalya Kajuri @kajunut.bsky.social · 13/09/2026
Deeply saddened to learn that Rafael Sorkin is no more. One of the deepest and most original thinkers of quantum gravity and the pioneer of causal set theory, he was also among the nicest, gentlest physicists I have met.
image of rafael sorkin
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Nirmalya Kajuri @kajunut.bsky.social · 10/09/2026
Rage against the machine meet rage against the dying of light.
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Nirmalya Kajuri @kajunut.bsky.social · 03/09/2026
With six research students, I don't get time to pursue projects of my own. This little paper happened when I sat down one evening and worked through an old idea. I didn't think it was significant enough to publish but with some encouragement I did put it out ⚛️ arxiv.org/abs/2604.03003
arxiv.org
Black Hole Interior Operators and Dilatation Symmetry in Planar Black Branes
Planar AdS black branes have a scaling symmetry that maps a brane solution at one temperature to a solution at another. It is natural to expect that boundary representations of bulk field modes should...
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Nirmalya Kajuri @kajunut.bsky.social · 30/08/2026
In case you guys are missing this stuff
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Nirmalya Kajuri @kajunut.bsky.social · 16/07/2026
At CERN
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Nirmalya Kajuri @kajunut.bsky.social · 16/07/2026
If I have pain in my shoulders, it is because this Newton asshole kept standing on them: giant
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Nirmalya Kajuri @kajunut.bsky.social · 16/07/2026
Spotted at CERN
Virgin/Chad meme involving LHC physicist and neutrino enjoyer
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Nirmalya Kajuri @kajunut.bsky.social · 10/07/2026
I am at CERN. Come say hi if you are around ⚛️
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Nirmalya Kajuri @kajunut.bsky.social · 08/07/2026
Heard they invented the www here or something ⚛️
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Nirmalya Kajuri @kajunut.bsky.social · 25/06/2026
Theoretical high energy physics ended today. Everyone saw Witten use Opus and decided to give up ⚛️
Arxiv shows no new lisings in hep-th today
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Reposted by Nirmalya Kajuri
Sean Carroll @seanmcarroll.bsky.social · 10/06/2026
“Everything fits, nothing is broken, and I think that makes the puzzle that is our universe even better,” said Kokorev. science.nasa.gov/missions/web...
science.nasa.gov
NASA Webb Finds Strongest Evidence Yet for ‘Black Hole Stars’ - NASA Science
The complex puzzle known as little red dots has become more complete since their initial discovery by NASA’s James Webb Space Telescope in 2022. Now a
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Nirmalya Kajuri @kajunut.bsky.social · 10/06/2026
My workspace
Desk with a view of mountains.
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Nirmalya Kajuri @kajunut.bsky.social · 10/06/2026
⚛️
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Nirmalya Kajuri @kajunut.bsky.social · 09/06/2026
New paper! Two recent approaches to black hole information loss paradox are islands and holography of information (HoI). We studied HoI in a 2d gravity model and investigated the difference between HoI and islands. Our result says that they correspond to different quantizations.
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Nirmalya Kajuri @kajunut.bsky.social · 04/06/2026
Planning to be in Europe in July but in a bit of a pickle with Visa issues. I booked my return on 30 July, but my visit to CERN ends on the 17th. I need an official invitation for the interim. If anyone in Schengen lands would beinterested to host me at their uni bw July 20-29, send me a DM. ⚛️
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Nirmalya Kajuri @kajunut.bsky.social · 24/05/2026
Real Estate Agent: It’s a wonderful neighbourhood. Very warm, very friendly. Everyone knows everyone, people are always dropping in, borrowing stuff, checking on each other. Honestly? It’s one of the most close-knit communities I’ve ever seen. Physicist (disappointed): So not Hausdorff?
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Nirmalya Kajuri @kajunut.bsky.social · 11/05/2026
Paul Painlevé was a mathematician who served twice as the prime minister of France. Georges Lemaître was a pioneer of cosmology and also a Catholic priest. These days we have tech bruhs larping as physicists and mathematicians.
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Nirmalya Kajuri @kajunut.bsky.social · 06/05/2026
⚛️🧪 If you don't like tree level Feynman diagrams for phi-cubed theory you can just
image shows s-channel, t-channel and u-channel Feynman diagrams with a f in between, spelling stfu
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Nirmalya Kajuri @kajunut.bsky.social · 04/05/2026
Pauli once told von Neumann the result of a difficult physical problem and how he had arrived at it. Von Neumann replied that the same result could be derived from just one axiom. Pauli responded, 'Herr von Neumann! If physics could be done with axioms, you'd be a great physicist!' ⚛️🧪
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Nirmalya Kajuri @kajunut.bsky.social · 28/04/2026
The man who ensured Einstein never won a Nobel prize for relativity was an eye doctor. Ironically, he ended up making an important contribution to Einstein’s theory. This is the story of Allvar Gulstrand ⚛️🧪 nirmalyakajuri.substack.com/p/einsteins-...
nirmalyakajuri.substack.com
Einstein's Nemesis
Story of a genius who tried to disprove Einstein
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Nirmalya Kajuri @kajunut.bsky.social · 28/04/2026
The man who ensured Einstein never won a Nobel prize for relativity was an eye doctor. Ironically, he ended up making an important contribution to Einstein’s theory. This is the story of Allvar Gulstrand ⚛️🧪 nirmalyakajuri.substack.com/p/einsteins-...
nirmalyakajuri.substack.com
Einstein's Nemesis
Story of a genius who tried to disprove Einstein
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Nirmalya Kajuri @kajunut.bsky.social · 27/04/2026
In 1939, Einstein wrote a paper which claimed that black holes cannot form. Even though his own theory of general relativity predicted their possibility, Einstein believed that they were bugs of the maths, not features of the world. In this paper, he set out to prove it. 🧵⚛️🧪
Image of Einstein's 1939 paper title "On a stationary system with spherical symmetry consisting of many gravitating masses"
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Nirmalya Kajuri @kajunut.bsky.social · 07/04/2026
I wrote up a small observation I had on the interplay between symmetries and state-dependent operators. arxiv.org/abs/2604.03003
arxiv.org
Black Hole Interior Operators and Dilatation Symmetry in Planar Black Branes
Planar AdS black branes have a scaling symmetry that maps a brane solution at one temperature to a solution at another. It is natural to expect that boundary representations of bulk field modes should...
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Nirmalya Kajuri @kajunut.bsky.social · 03/04/2026
New preprint, with my students Arundhati Goldar and Rhitaparna Pal! We extend Grinberg-Maldacena's result that the boundary thermal one-point function encodes the bulk geodesic distance from boundary to singularity in AdS black holes, to 3D de Sitter black holes. arxiv.org/abs/2603.21425
arxiv.org
Holographic One-Point Function and Geodesics in SdS$_3$
Grinberg-Maldacena showed that, for AdS/CFT, the thermal one-point function of a heavy boundary operator in the dual conformal field theory encodes the complex geodesic length from the boundary insert...
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Reposted by Nirmalya Kajuri
Eugene Lim @tukohbin.bsky.social · 02/04/2026
My students printed out my General Relativity lecture notes from a few years ago and made this cover for it!
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Nirmalya Kajuri @kajunut.bsky.social · 01/03/2026
*Takes the tiniest possible bite* "That's a big bite!" If I didn't read the description, I would have thought this was a comedy skit
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Nirmalya Kajuri @kajunut.bsky.social · 28/02/2026
Me: solve the equations x+y=5, x-y=3 Chatbot: (thought for 17 minutes) Simultaneous equations can be tricky. The equations you want solved are x+y=5, x-y=3. If we substitute x=z, y=w, the equations simplify to z+w=5, z-w=3. The next step would be to solve it. Just say the word. 1/3
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Nirmalya Kajuri @kajunut.bsky.social · 26/02/2026
Special relativity does not rule out faster-than-light signals? There's a strong argument showing that it need not. Hat tip to @uberwensch.bsky.social who shared a paper and initiated a discussion that inspired this post nirmalyakajuri.substack.com/p/faster-tha...
nirmalyakajuri.substack.com
Faster than Light Travel, Free from Paradoxes
No grandfathers were hurt in the writing of this article
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Nirmalya Kajuri @kajunut.bsky.social · 24/02/2026
Thinking about hanging this clock in my office to remind me of the problem of time in canonical quantum gravity
Clock with no hands
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Nirmalya Kajuri @kajunut.bsky.social · 22/02/2026
There's so many physicists here on Blusky yet I never see any real discussion or dialogue on any physics topic despite following the physics feed and every physicist in my areas of interest. Am I missing them? What can we do to spark some physics conversations? ⚛️🧪
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Nirmalya Kajuri @kajunut.bsky.social · 21/02/2026
Ravi Vakil on learning mimetically from seminars. The backfilling part is my favorite--it feels like a blurry picture finally coming sharply into focus!
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Nirmalya Kajuri @kajunut.bsky.social · 21/02/2026
Just a tiny croc sunbathing in my office
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Reposted by Nirmalya Kajuri
Astrobites @astrobites.bsky.social · 21/02/2026
From Akshita Mittal: Can a sneezing ant destroy a black hole? Regge and Wheeler set out to find out. ⚛️ 🔭 ☄️ 🧪 astrobites.org/2026/02/18/w...
astrobites.org
What happens when you poke a black hole?
Can a sneezing ant destroy a black hole? Regge and Wheeler set out to find out.
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Nirmalya Kajuri @kajunut.bsky.social · 18/02/2026
Drinking game for high energy physicists: While checking arXiv, take a shot whenever you encounter one of these terms Unparticles Chameleons Fakeons Spurions WIMPzilla Axions Relaxions Dark Photons Fuzzball Galileons Curvatons Ghost Condensate Cuscatons Fractons ⚛️🧪
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Nirmalya Kajuri @kajunut.bsky.social · 17/02/2026
Here's a fun fact you can use to break the ice at parties. Whether a point is inside a black hole horizon or not depends on the entire future of spacetime. You're welcome. ⚛️🧪
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Nirmalya Kajuri @kajunut.bsky.social · 17/02/2026
Can a black hole replace the Large Hadron Collider? Rapidly rotating (Kerr) black holes can accelerate particles to enormously high energies., provided the particles have finetuned values of angular momentum. It can dwarf any accelerator on earth! But.. 1/3 ⚛️🧪
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Nirmalya Kajuri @kajunut.bsky.social · 14/02/2026
An important skillset for physicists is the mastery of computational techniques. With the advent of AI, this particular skillset looks like the first to be replaced. Wonder what this will mean for the the subset of physicists for whom this was the primary skillset. 🧪⚛️
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Nirmalya Kajuri @kajunut.bsky.social · 14/02/2026
Very cool! The field of scattering amplitudes involves working with massive algebraic expressions and finding patterns in them. Which is exactly the sort of thing AI is great at. Expect AI to become indispensable to this field. ⚛️🧪
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Nirmalya Kajuri @kajunut.bsky.social · 13/02/2026
You may have heard that spacetime is geometry, but what if I told you that even Newton’s laws are geometric? Newton’s laws say: if you tell me position and momentum of a system now, I can figure what they will be at any future point by solving equations given by Newton’s laws.. 1/4 ⚛️🧪
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Nirmalya Kajuri @kajunut.bsky.social · 01/02/2026
Physicist Ivette Fuentes turned down Epstein money: "The dream of my life is to build a gravitational-wave detector..So, if someone were to say to me, ‘I'll give you the money to make your dream come true,' it would be very tempting to say yes. But then you have your ethical standards." ⚛️🧪
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Nirmalya Kajuri @kajunut.bsky.social · 29/01/2026
Average PhD in Amplitudes ⚛️
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Nirmalya Kajuri @kajunut.bsky.social · 28/01/2026
Ed Witten, the journalist? ⚛️🧪
Jim Downey asking for clarification
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Nirmalya Kajuri @kajunut.bsky.social · 27/01/2026
Campus looking good these days (photo by Munna Kumar)
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Nirmalya Kajuri @kajunut.bsky.social · 27/01/2026
Is that particle physics in your pocket or are you just happy to see me 🧪⚛️
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Nirmalya Kajuri @kajunut.bsky.social · 21/01/2026
As an ADHD-haver, AI helps me reduce the activation cost of starting tasks. Say I need to check for mistakes in a long computation. I let AI have a look, then check its report. After a bit of back and forth, I know where the mistakes might be. At that point I'm ready to dive in. ⚛️🧪
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