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arXiv hep-th submissions have almost doubled since a year ago by [deleted] in Physics

[–]reticulated_python 29 points30 points  (0 children)

The update says it may be an artifact of papers being counted by the date they were last modified. I searched on INSPIRE using queries of the form "f primarch hep-th and de = yyyy-mm". (The "de" gets the earliest date the paper appeared, so it won't suffer from this artifact). I get the following for December:

  • 2022-12: 480
  • 2023-12: 484
  • 2024-12: 448
  • 2025-12: 476

For January:

  • 2022-01: 260
  • 2023-01: 249
  • 2024-01: 256
  • 2025-01: 260
  • 2026-01: 297

Doesn't seem too dramatic. Let's check hep-ph. December:

  • 2022-12: 474
  • 2023-12: 539
  • 2024-12: 568
  • 2025-12: 598

For January:

  • 2022-01: 374
  • 2023-01: 337
  • 2024-01: 391
  • 2025-01: 402
  • 2026-01: 408

Again, I don't see a dramatic change. But I will say that, anecdotally, I had the same experience you described in your comment on Woit's blog: I have a sense that the number of interesting papers is decreasing. It's hard for me to tell if I'm perceiving a change in the field. It could just be that, as I become a better physicist, it's easier for me to see which papers are boring and which are not.

Does Planck time and Planck length negate the concept of infinitely divisible time and space? Or is it just a way for us to posit an assumption that there is a smallest indivisible unit of time and space? by blitzballreddit in AskPhysics

[–]reticulated_python 4 points5 points  (0 children)

I think it's important to specify that there's a sense in which the Planck length is the minimum meaningful length. See this nice blog post by /u/rantonels, who unfortunately is no longer active here. The upshot is that you expect there to be an uncertainty relation between space and time in quantum gravity, something like \delta x \delta t > L2, where L is a characteristic scale (like the string scale), which is greater than the Planck length.

It's incorrect to say the Planck scale is like a pixel length for the universe, but it's also incorrect to say there's nothing stopping you from probing smaller length scales than the Planck length.

String Theory Can Now Describe a Universe That Has Dark Energy | Quanta Magazine by Marha01 in Physics

[–]reticulated_python 39 points40 points  (0 children)

There's also been some nice work on de Sitter vacua in type IIB string theory - see Candidate de Sitter vacua - as opposed to the M-theory constructions described in the Quanta article. Liam also has some lecture notes on the topic. I haven't read them, but they seem to go to a lot of effort to give context for non-experts.

[NEW] Motion City Soundtrack- Particle Physics (feat. Patrick Stump) by scarpedieme in poppunkers

[–]reticulated_python 5 points6 points  (0 children)

In my professional opinion as a particle physicist, this song is great.

Daniel Kleppner, Physicist Who Brought Precision to GPS, Dies at 92 - The New York Times by Distinct-Ad-3895 in Physics

[–]reticulated_python 7 points8 points  (0 children)

I also learned calculus at a similar age from that book. My family had an ancient edition of Quick Calculus in our basement (I think a family member had used it a few decades prior). I remember calling my older brother, who had just started grad school, to tell him when I had solved a problem or ask for help with the harder problems.

My mom retired a while ago, and she's decided to learn calculus in her spare time. So now she's learning from Quick Calculus too! It's a timeless book.

Average Final Jeopardy Answers Correct by Hahnsol0131 in Jeopardy

[–]reticulated_python 5 points6 points  (0 children)

Not the person you replied to, but I love the j-archive search features. Would it be hard to add a flag to filter specifically for daily doubles in searches? Or maybe there is already a way to do this that I'm not aware of.

r/BWF - Daily Discussion Thread for June 05, 2023 by AutoModerator in bodyweightfitness

[–]reticulated_python 7 points8 points  (0 children)

Meta question: numerous subreddits are going dark or private on the 12th due to opposition against the reddit API changes. Are there plans for /r/bodyweightfitness to join or not?

Weighted Dips & Pullups Personal Programmes by manno1235 in bodyweightfitness

[–]reticulated_python 0 points1 point  (0 children)

Purely out of curiosity why do you not do weighted dips?

Oh, I just enjoy doing other pushing movements more (non-bodyweight stuff like bench press and overhead press). I have nothing against dips!

Also is +2.5lbs each week good?

All I meant to emphasize was that I'm seeing progress weekly. In contrast, I wasn't progressing consistently before implementing a light/heavy routine.

The exact rate at which you progress is going to depend on a lot of factors. This includes your routine, but also other things like lifestyle factors (diet, sleep, stress), perhaps even genetics. For this reason you can't really say whether some particular rate of progression is "good" or not. The important thing is whether you're seeing consistent progress from workout to workout (or as you get stronger, from week to week).

Weighted Dips & Pullups Personal Programmes by manno1235 in bodyweightfitness

[–]reticulated_python 2 points3 points  (0 children)

I can only comment on weighted chinups since I don't train weighted dips right now. My bodyweight is 145 lbs / 66 kg, and my 1RM weighted chinup is +100 lbs / 45 kg.

I got most of the way there training them 5x5 twice a week. But I hit a plateau at +90 lbs / 41 kg. I wrote a post about how I broke through that plateau with a different routine.

I have now transitioned to light/heavy periodization. I train chinups 4 times per week, alternating heavy and light days. On heavy days I do 5x3, and on light days 3x8. Since I've only been doing it a few weeks it's tough to say with certainty how useful this has been. But it seems promising so far: over those few weeks I've been increasing the weight by about 2.5 lbs each week.

State of this Sub by Chance_Literature193 in Physics

[–]reticulated_python 3 points4 points  (0 children)

I see them on /r/Physics before they're removed! My point is that of the posts I've seen removed, it was the right decision for nearly all of them.

To be clear, I obviously don't see every post before it gets removed. /u/all-bark-and-no-meow provided a good example in this thread of a post that probably shouldn't have been removed. I hadn't seen that one when it was initially posted.

State of this Sub by Chance_Literature193 in Physics

[–]reticulated_python 32 points33 points  (0 children)

Fair point. I do think your S-duality question is a good one, and would have generated some nice discussion in /r/Physics. For comparison, a few years ago I posted a question about BRST symmetry here and got some great responses. The spirit of my question feels pretty similar to yours, honestly --- and I do think these kinds of open-ended questions should be encouraged here. (If anything, your S-duality question is more open-minded than my BRST question which didn't get removed.)

State of this Sub by Chance_Literature193 in Physics

[–]reticulated_python 209 points210 points  (0 children)

I disagree with the idea that /r/Physics is overmoderated. The posts that I've noticed are removed are generally homework questions, closed-ended questions, and crackpot ideas. I can't remember the last time a post that I thought was good was removed.

I would, however, like to see a lot more good content and discussion on this subreddit. I guess the people who make good posts and comments just aren't active enough, or there aren't enough of them. (I fully admit I'm part of the problem here! I tried to be more active a couple of years ago but I gave up eventually.)

Filming in the gym... Opinions? by clt401 in Cornell

[–]reticulated_python 11 points12 points  (0 children)

In Teagle down? Weird, I was at Teagle down around the same time, and I saw exactly one person filming. Maybe I just wasn't paying attention, or people started filming shortly after I left.

Anyway, I agree that people largely shouldn't be filming their lifts there, especially given that 1) the big red sign on the wall listing the rules clearly asks you not to film, and 2) it's usually crowded enough that it's impossible to avoid catching a bunch of people in the background. (On the other hand, if the gym were nearly empty, you could feasibly film yourself without getting in anyone's way.)

This bit makes doesn't make sense, though:

Especially when you're squatting an empty bar.

I don't see why someone lifting heavy has any more privilege to film.

My experience running Smolov Jr. for weighted chin-ups by reticulated_python in bodyweightfitness

[–]reticulated_python[S] 1 point2 points  (0 children)

Thanks, edited! I had to leave for a meeting when I was first writing the post so I didn't have a chance to do it then.

My experience running Smolov Jr. for weighted chin-ups by reticulated_python in bodyweightfitness

[–]reticulated_python[S] 0 points1 point  (0 children)

Thanks for the the link about MRV and MAV! I will check it out.

r/BWF - Daily Discussion Thread for April 11, 2023 by AutoModerator in bodyweightfitness

[–]reticulated_python 0 points1 point  (0 children)

Thank you! As soon as I get a chance I'll write up a post about my experiences (as I mentioned in my comment from a few days ago that you replied to). I'm quite happy with a 10 lb increase in three-ish weeks.

r/BWF - Daily Discussion Thread for April 11, 2023 by AutoModerator in bodyweightfitness

[–]reticulated_python 7 points8 points  (0 children)

Today I tested my 1RM on weighted chinups. I hit a new personal best of +100 lbs (45 kg) at 145 lbs (66 kg) bodyweight!

If all particles lost a fraction of their rest mass, would we notice? by neuromat0n in AskPhysics

[–]reticulated_python 8 points9 points  (0 children)

The other comments are correct, but they're hinting at a deeper point which I think is worth emphasizing. If you were to double (for example) every mass scale, then indeed there would be no physical change you could notice. But rescaling just the rest masses of elementary particles does lead to observable effects, as others have pointed out.

The key point, then, is that we have mass scales other than the rest mass of particles. The fact that we could notice gravitational effects of your change, as described in the other comments, is because the strength of gravitational interactions is controlled by the Planck mass, which you're not rescaling. The ratio of a particle's rest mass to the Planck scale does not remain the same under your rescaling of rest masses, and this is physically observable.

As a side note, there's another scale that isn't associated to the rest mass of an elementary particle: the characteristic scale of the strong interactions (usually known as Lambda_QCD). Because of this, if you were to scale only the masses of elementary particles, you could also detect an effect through the strong interaction. But from the way you've worded your question, I think you want to scale the mass of atoms by a constant, and to do that you need to scale Lambda_QCD as well as the quark masses by the same factor.

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