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Posts by nicholas rui

Something is poppin in the state of Denmark

9 months ago 1 0 0 0

my hottest educational take is that schools should actively, non-punitively teach students how to admit when they don't know something, aren't sure or have made a mistake, with various teaching frameworks adapted to support this ideal, because people who can't admit fault are breaking the world

10 months ago 5307 1475 81 111

congrats!

10 months ago 1 0 1 0
My cat Alfvie, a gray and brown tabby, stretched out on the couch with his stripes exposed.

My cat Alfvie, a gray and brown tabby, stretched out on the couch with his stripes exposed.

This is my cat, Alfvie. In my last thread, I mentioned that he’s very cute – this is still true. But how are Alfvie’s stripes like the magnetic fields in a plasma?

A thread on Alfvén’s theorem [15 posts]:

#astronomy #astroedu #cats

11 months ago 34 4 4 1

Thank you so much!!

1 year ago 2 0 0 0

Apparently making a bid for the record for the largest number of illegal and unconstitutional declarations to be fit inside just one short social media post

1 year ago 1264 158 43 7

Undergraduate research opportunities are incredibly valuable, both for the students and for the progress of the work. And having undergraduate research experience is a massive help for grad school admission. REU cancellations harm students’ preparedness & career prospects, and slow research progress

1 year ago 721 181 13 26
Screenshot of the title/auth list/abstract:

Length dependence of waveform mismatch:
a caveat on waveform accuracy

Keefe Mitman, Leo C. Stein, Michael Boyle, Nils Deppe, Lawrence E. Kidder, Harald P. Pfeiffer, Mark A. Scheel

Abstract. The Simulating eXtreme Spacetimes Collaboration’s code SpEC can now routinely simulate binary black hole mergers undergoing ∼ 25 orbits, with the longest simulations undergoing nearly ∼ 180 orbits. While this sounds impressive, the mismatch between the highest resolutions for this long simulation is O(10^−1). Meanwhile, the mismatch between resolutions for the more typical simulations tends to be O(10^−4), despite the resolutions being similar to the long simulations’. In this note, we explain why mismatch alone gives an incomplete picture of code—and waveform—quality, especially in the context of providing waveform templates for LISA and 3G detectors, which require templates with O(10^3) − O(10^5) orbits. We argue that to ready the GW community for the sensitivity of future detectors, numerical relativity groups must be aware of this caveat, and also run future simulations with at least three resolutions to properly assess waveform accuracy.

Screenshot of the title/auth list/abstract: Length dependence of waveform mismatch: a caveat on waveform accuracy Keefe Mitman, Leo C. Stein, Michael Boyle, Nils Deppe, Lawrence E. Kidder, Harald P. Pfeiffer, Mark A. Scheel Abstract. The Simulating eXtreme Spacetimes Collaboration’s code SpEC can now routinely simulate binary black hole mergers undergoing ∼ 25 orbits, with the longest simulations undergoing nearly ∼ 180 orbits. While this sounds impressive, the mismatch between the highest resolutions for this long simulation is O(10^−1). Meanwhile, the mismatch between resolutions for the more typical simulations tends to be O(10^−4), despite the resolutions being similar to the long simulations’. In this note, we explain why mismatch alone gives an incomplete picture of code—and waveform—quality, especially in the context of providing waveform templates for LISA and 3G detectors, which require templates with O(10^3) − O(10^5) orbits. We argue that to ready the GW community for the sensitivity of future detectors, numerical relativity groups must be aware of this caveat, and also run future simulations with at least three resolutions to properly assess waveform accuracy.

Fig 2 from the preprint, which shows mismatch (between resolutions) as a function of length of time interval over which the mismatch is computed. There are 4 curves, each going roughly like M ~ t^2. The four curves are in two groups: Two from simulations SXS:BBH:1412, and two from SXS:BBH:1132. Each simulation has two different truncation error comparisons: med vs. low and high vs. med. They both show convergence.

Fig 2 from the preprint, which shows mismatch (between resolutions) as a function of length of time interval over which the mismatch is computed. There are 4 curves, each going roughly like M ~ t^2. The four curves are in two groups: Two from simulations SXS:BBH:1412, and two from SXS:BBH:1132. Each simulation has two different truncation error comparisons: med vs. low and high vs. med. They both show convergence.

Wake up babe, new preprint just dropped

Length dependence of waveform mismatch:
a caveat on waveform accuracy
Mitman, Stein, et al.
arxiv.org/abs/2502.14025

⚛️🧪🔭

1 year ago 17 2 0 1

congrats!!

1 year ago 0 0 0 0

oh no officer, i'm not for dei, i'm simply an avid fan of multi-wavelength observations

1 year ago 1 0 0 0
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Really happy to see more people doing this! I started a collection here; please let me know if you've made your own papper annotation or seen one I missed: cmlamman.github.io/paper_doodle...

1 year ago 24 5 1 0

he got put down :(

1 year ago 0 0 0 0

it’s my main fear too, and that the guardrails are off, but clinging to whatever hope there is tbh

1 year ago 1 0 0 0

shaping up like this Trump admin, despite being staffed by bigger sycophants, may still not avoid the daily infighting of the previous one

1 year ago 1 0 1 0

i’ll say this: i did a video on tiktok about the fact that federal limits on abortion would supersede all state protections and a lot of people refuse to believe it

1 year ago 4187 744 165 56
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“The fate of the American republic will depend on how willing Americans are to take up the fight.”

Found this from @vox.com newsletter this am helpful for my mindset

1 year ago 152 47 7 5
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Reskeet to save someone’s fucking life

2 years ago 9793 10127 40 105

I like the ones that are along the lines of, "Since I was 12 years old, it has been my dream to advance the field of Gaussian process regression..."

1 year ago 6 1 1 0

petition to measure sound intensity in magnitudes

2 years ago 1 0 0 0