Kartik Prabhu
Some weekend reading: two new papers on blackholes
Canonical Energy and Hertz Potentials for Perturbations of Schwarzschild Spacetime http://arxiv.org/abs/1807.09883
Symmetries and charges of general relativity at null boundaries http://arxiv.org/abs/1807.11499
Kartik Prabhu
Kartik Prabhu
This is so much cooler than the digital one I made for a lab class once!
Kartik Prabhu
reposted

a post on Twitter
because

Totally on point.
Kartik Prabhu
Kartik Prabhu
Here’s my talk on “Conservation of asymptotic charges from past to future null infinity” for #apsapril : https://kartikprabhu.com/static/talks/Conservation-of-asymptotic-charges-from-past-to-future-null-infinity-APS2018/conservation-asymptotic-charges-past-future-null-infinity.html
Come see it anyway on April 16 at 10:45 Session R13
Kartik Prabhu
reposted

a post on Twitter
because

Must read thread.
Kartik Prabhu
Looks like the blackhole stability problem is getting some press https://www.quantamagazine.org/to-test-einsteins-equations-poke-a-black-hole-20180308/
Kartik Prabhu
Rounding up the usual suspects
1) supersymmetry
2) dark matter
3) MoND
4) quantum gravity
Kartik Prabhu
My bet is on tomorrow!
Kartik Prabhu
new stuff with Bob Wald on stability of black holes to axisymmetric electromagnetic perturbations https://arxiv.org/abs/1708.03248
Kartik Prabhu
yes, https://en.wikipedia.org/wiki/Homogeneous_space#Homogeneous_spaces_as_coset_spaces even though I don’t know what you mean by “isometry”.
Kartik Prabhu
OK everyone, back to work. Quantum Gravity is not going to figure itself out!
Kartik Prabhu
In which signature is the “conservation of convention law” stated?
Kartik Prabhu
‘I know, I’ll use Latex macros’ Now you have two problems (also see https://xkcd.com/208/ and https://xkcd.com/927/ )
Kartik Prabhu
hopefully you are using the maths convention — phi_^* for pullback since it is a “dual map”
Kartik Prabhu
there are worse convention-violations in GR; signature, Riemann tensor, extrinsic curvature… comparatively this is not a big deal!
Kartik Prabhu
because it is consistent with the index positions for objects being pulled-back, forms, vs objects being pushed-forward, vectors.
Kartik Prabhu
lot of awesome number theory here — primes, factorisation, Gaussian primes, character functions — pretty neat!
Kartik Prabhu
I never realised that you can get all Pythagorean triples from complex numbers!
Kartik Prabhu
“but much to say about humanity”
nice thoughts on Minority Report and Artificial Intelligence. Sci-fi is best when it is not about the technology but about humans.
Kartik Prabhu
nice demonstration of equilibrium and stability.
Kartik Prabhu
Talked about Canonical energy & linear stability of Schwazschild https://kartikprabhu.com/static/talks/Canonical-energy-and-linear-stability-of-Schwarzschild-APS2017/canonical-energy-linear-stability-schwarzschild.html #apsapril
Kartik Prabhu
Bob Wald’s advice on doing science: Drink lots of coffee and talk to people. #apsapril
Kartik Prabhu
this video by @TheeNerdwriter summarises everything that I disliked about Interstellar… and yes I am a physicist.