Notes

tagged physics

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
Great interview with physicist Sau Lan Wu https://www.quantamagazine.org/sau-lan-wus-three-major-physics-discoveries-and-counting-20180718/
Kartik Prabhu
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
new stuff with Bob Wald on stability of black holes to axisymmetric electromagnetic perturbations https://arxiv.org/abs/1708.03248
Kartik Prabhu
replied to a post on Twitter with
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
replied to a post on Twitter with
OK everyone, back to work. Quantum Gravity is not going to figure itself out!
Kartik Prabhu
replied to a post on Twitter with
In which signature is the “conservation of convention law” stated?
Kartik Prabhu
replied to a post on Twitter with
‘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
replied to a post on Twitter with
hopefully you are using the maths convention — phi_^* for pullback since it is a “dual map”
Kartik Prabhu
replied to a post on Twitter with
there are worse convention-violations in GR; signature, Riemann tensor, extrinsic curvature… comparatively this is not a big deal!
Kartik Prabhu
replied to a post on Twitter with
because it is consistent with the index positions for objects being pulled-back, forms, vs objects being pushed-forward, vectors.
Kartik Prabhu
nice demonstration of equilibrium and stability.
Kartik Prabhu
Bob Wald’s advice on doing science: Drink lots of coffee and talk to people. #apsapril