lupsasca

7 ms·

1.
by lupsasca 7mo ago
Hi, I'm an author on the paper. It was definitely a human-AI collaboration, but it is also true that the final simplified formula, Eq. 39 in the paper (which is what we had been seeking, without success), was conjectured and proved by
2.
by lupsasca 7mo ago
Correct, on both counts!
3.
by lupsasca 7mo ago
My pleasure---thank you for your interest!
4.
by lupsasca 7mo ago
There are closely related "MHV amplitudes" which naively obey a really complicated formula, but for which there famously also exists a much simpler "Parke-Taylor formula". Alfredo had derived a complicated expression for
5.
by lupsasca 7mo ago
That paper from the 80s (which is cited in the new one) is about "MHV amplitudes" with two negative-helicity gluons, so "double-minus amplitudes". The main significance of this new paper is to point out that "single
6.
by lupsasca 7mo ago
Hi I am an author of the paper. We believed that a simple formula should exist but had not been able to find it despite significant effort. It was a collaborative effort but GPT definitely solved the problem for us.
7.
by lupsasca 8mo ago
By "grabbing references" I meant queries of the type "add paper [bla] to the bibliography" -- that seems useful to me!
8.
by lupsasca 8mo ago
I am very sympathetic to your point of view, but let me offer another perspective. First off, you can already vibe-write slop papers with AI, even in LaTeX format--tools like Prism are not needed for that. On the other hand, it can really h
9.
by lupsasca 2y ago
About ~5x improvement. Recall that the resolution of an interferometric array is set by the distance between telescopes measured in units of the observation wavelength. BHEX will get a ~3x resolution improvement from the increased distance
10.
by lupsasca 2y ago
We're thinking about it! Likely 2025 though.
11.
by lupsasca 2y ago
If you put the source infinitely far away (as we are doing here) and at zero velocity relative to the camera, then there is no redshift effect at all, so you could say that this is the choice of redshift that we made :) If you want the deta
12.
by lupsasca 2y ago
Not currently. As I mentioned elsewhere, the rotating black hole version that we implemented requires GPU code, and porting that to Android is nontrivial---though we'd love it if someone took our open-source code and ported it! In the
13.
by lupsasca 2y ago
Excellent! Hope it looked cool.
14.
by lupsasca 2y ago
Hahaha, I half-expected a plasma physicist to complain that GRRMHD is not self-consistent and we need to include non-ideal fluid effects :D
15.
by lupsasca 2y ago
That would be cool, but then you wouldn't be seeing the world around you anymore. In other words, at that point it becomes a GRMHD simulation, and there is no point in using cameras since the user's environment is obscured, no? Or
16.
by lupsasca 2y ago
I haven't looked into the equations but I expect the effect of varying the electric charge would be similar to (but less dramatic than) changing the spin of the black hole, which as you can see in our app is not that big of a change.
17.
by lupsasca 2y ago
The rotating black hole version that we implemented requires GPU code, and porting that to Android is nontrivial---though we'd love it if someone took our open-source code and ported it! In the meantime, check out this code developed b
18.
by lupsasca 2y ago
What the black hole looks like depends on how you define your field of view. And if the black hole is spinning, then you don't expect a circular shadow at all. But in our app, if you pick the "Static black hole" (the non-rota
19.
by lupsasca 2y ago
Yes, this is one of the wonderful crazy properties of black holes: they get hotter as they evaporate! (More precisely, the Hawking temperature is inversely proportional to the mass!)
20.
by lupsasca 2y ago
Glad to hear that! You'll probably also enjoy reading about the Black Hole Explorer (BHEX): a proposed space mission that will take the sharpest images in the history of astronomy and resolve the "photon ring" of orbiting lig
21.
by lupsasca 2y ago
I think what he showed you was likely a version of this that was coded up by Harvard graduate student Dominic Chang: https://dominic-chang.com/bhi-filter/ It works very well (and in a browser!) but is limited to a non-
22.
by lupsasca 2y ago
Yes, Andy has been very involved in the story of the photon ring and was one of the lead authors on the original paper that started it all: https://www.science.org/doi/10.1126/sciadv.aaz1310 (And he was also my Ph
23.
by lupsasca 2y ago
There are other apps out there for this kind of black hole vision...
24.
by lupsasca 2y ago
Yes, but one issue is that the amount of redshift depends on the motion of the emitter, so we would have to artificially assign some four-velocity to your surroundings in order to give them some redshift. There doesn't seem to be a &qu
25.
by lupsasca 2y ago
As Project Scientist for BHEX, I am of course excited about the project and eager to spread the word about it! But as I wrote in my other comment, what this is really trying to "sell" is gravitational physics to students intereste
26.
by lupsasca 2y ago
Adding options to drop the multi-camera view and to capture a screenshot is relatively straightforward, and I think we can implement that in the next update. Pinning the black hole to a specific place is a whole other undertaking...
27.
by lupsasca 2y ago
Yes, such a great game---it's a fantastic visualization of special relativity and also fun to play! I think we're still a ways off from real time GRMHD sims, but CK Chan from UArizona had a working VR simulation (on the Oculus iir
28.
by lupsasca 2y ago
Glad it worked on second boot! We used to have some bugs in the elliptic integral implementation that led to the app crashing, but we think we've eliminated those, so hopefully this is just a fluke... Anyone else with this issue?
29.
by lupsasca 2y ago
Glad to hear you're excited about BHEX---we are too! If you want to read more about what it's going to do, I wrote a blog post about it on the mission website: https://www.blackholeexplorer.org/bhex-blog/lupsa
30.
by lupsasca 2y ago
The black hole simulation that was shown in the movie Interstellar is explained in detail in this paper, freely available on the arXiv: https://arxiv.org/abs/1502.03808 As a physicist with a modest background in comput

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