Nick

Theoretical physicist by training (quantum open systems/quantum information), Currently paying the bills as an engineer working in free-space optical communication. I also enjoy the outdoors and learning about any area of science, philosophy, and many other academic areas as well.

Pronouns: he/him/his
Moved here from: qoto.org

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npub1ud2636xg9cp3x2tem5ppz8cpks35teulcqdxeddfwst2t70x20tqfmg5ez

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internic_at_mathstodon.xyz@momostr.pink

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nprofile1qqswx4dgaryzuqcn99ua6qs3ruqmgg69u70uqxnvkk5hg949l8n984sprpmhxue69uhhyetvv9ujumt0d4hhxarj9ecxjmntqyv8wumn8ghj7un9d3shjtnndehhyapwwdhkx6tpdsnsefvh

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npub1ud2636xg9cp3x2tem5ppz8cpks35teulcqdxeddfwst2t70x20tqfmg5ez

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Last Notes

2026-10-22 04:10:12 UTC

RE: https://mastodon.com.br/@xkcd/117467520327623815
Ironically at first I didn't get the joke because from the first panel I was convinced this was going to be about the Farnsworth Fusor.
#note1x53…cc7m

2026-08-26 01:00:29 UTC

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I mean, you were certainly bothering the crackpots. 😜

2026-08-25 05:31:16 UTC

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Based on experiences from Usenet until now, I'm pretty sure that one of the key purposes of the Internet is bothering @npub1nf4…nqe4.

2026-08-15 15:53:41 UTC

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To be clear, my point was mostly related to special relativity, that if you have one particle you can seemingly just think about mass, because you can transform into a frame where it's stationary, but when you have many particles there will (usually) be no frame where they are all stationary, and you'll have to cope with how gravity arises from their full 4-momentum. It's just that the two examples I could immediately come up with where the momentum-related terms from the gravity source are important happen to come from the context of general relativity.
But yes, I'd say that if you're just coming to terms with special relatively I wouldn't yet venture into general relativity, as it builds on the former and it's vastly more subtle (at least, so it seems to me).

2026-08-15 03:24:04 UTC

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For a single particle (with non-zero mass), one can always choose the frame of reference where the particle is at rest, so it has no momentum and its only energy is the rest energy from its mass; in that sense perhaps you can think of the gravity as being due specifically to the mass.
But as soon as you have two or more particles in relative motion, then there is no frame of reference in which they are all at rest, and you have to include the effects of momentum (and stress) on gravity. When thinking of things in continuous terms, for example, the momentum portion exhibits as pressure, which contributes to the gravitational effects in relativity (this shows up in the mathematical descriptions stars and the large-scale cosmological structure of the Universe).

2026-08-15 02:51:08 UTC

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It's not immediately clear to me how salient that point is, though.
Consider a universe consisting of two subsystems, the first can only be in states spanned by |a> and |b> and the second one can only be in states spanned by |c> and |d>. If the first subsystem is initially in the state \[\frac{1}{\sqrt{2}}\left(|a>+|b>)\right)\] and the second subsystem initially in state |c> "measures" subsystem 1 as a CNOT putting this universe into the state \[\frac{1}{\sqrt{2}}\left(|a>|c>+|b>|d>)\right)\]. Now obviously this final state is just one vector in a 4D Hilbert space, but it represents branches where subsystem 1 is in each of its possible basis states and subsystem two is in the corresponding measurement record state. The other orthogonal state vectors represent either states with differences in phase that make no difference to the observer or states that are now allowed by the (contrived) physics given the initial conditions (e.g. |a>|d> and |b>|c>).
Perhaps it all comes down to figuring out which macroscopic events are actually allowed (if improbable) by the microscopic physics.

2026-07-19 21:14:09 UTC

I was watching this video about passkeys recently and when they got to the part about a site being able to specify what sort of device was being used for the authentication it struck me again how passkeys will always be a technology that works for the oligopolies who created it, not the user. I hate using passwords for authentication, but for all their faults they are a thing users understand and are ultimately in control of, and sadly, for all their benefits, passkeys will never be.
https://www.youtube.com/watch?v=lypcC79k-gg

2026-05-26 01:09:23 UTC

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Counterpoint: Human ingenuity is sometimes pretty awesome.
https://youtu.be/YdOXS_9_P4U

2026-05-25 23:15:45 UTC

Current mood:
https://media.mathstodon.xyz/media_attachments/files/116/637/752/819/618/467/original/855826f77e711749.png

2026-05-04 17:05:56 UTC

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It seems very odd for a atheistic biologist to assert that consciousness is "for" anything. Or perhaps he means ..."what the hell is *the word* consciousness for?"

2026-04-19 22:34:34 UTC

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Not that I'm saying there's any relationship whatsoever, but am I the only one that saw the portion of the diagram at left an immediate had Penrose diagrams pop into their head? 😄

2026-04-18 21:29:22 UTC

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Yes, it for the proving of theorems I can see why "reasoning" would be important. And I agree that the agentic aspect is useful for the other purposes you describe (though with potential drawbacks related to things like security).

2026-04-18 20:46:14 UTC

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You said "I suspect you have not used modern agentic AI tools to solve advanced math problems." Is the agentic aspect important here? I would have thought this would be more of a good old fashion LLM type of problem (produce the text of a proof in response to the a description of what it should contain), but perhaps there are aspects here I don't understand.

2026-04-05 01:14:59 UTC

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This seems to be a result no one can make immediate use of, so I don't see how "responsible disclosure" applies.

2026-02-11 01:33:25 UTC

A question for science and engineering folks: What's your go to desktop software for easily plotting data (say multiple series containing up to 100000 points each)? (Note: not a cloud service unless it's implemented fully client side in JS or something.)
My current go to is probably a spreadsheet or matplotlib in Python, but I would not call either ideal.

2026-01-11 13:52:06 UTC

What I imagine every time someone mentions Max Q during a rocket launch.
https://media.mathstodon.xyz/media_attachments/files/115/876/782/703/009/190/original/aa2c075f6e480135.mp4

2025-12-26 18:24:16 UTC

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I think I have similar frustrations to yours [@j_bertolotti](https://mathstodon.xyz/@j_bertolotti ). I remember many years ago when I heard some traditional Chinese music for the first time, and hearing that in comparison to the European-derived music I was used to made plain to me how much of what we think of as "the way music works" is historically or culturally contingent. It seems to me that music theory arises from three things, math/physics, intrinsic human psychoacoustic perceptual characteristics, and cultural conventions. But most of the discussion of music theory doesn't seem to distinguish which is which, and I find that rather confusing.
I suspect that if I spent more time reading music threads by @npub1nf4…nqe4 I might be able to resolve some of that confusion, though.

2025-11-04 06:01:39 UTC

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This just makes me think of when I was teaching physics, and I had pre-med students taking the course who were trying to prepare flashcards as a study aid. But, yes, prizing memorization seems even more absurd in that context.

2025-10-24 17:53:21 UTC

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We were losing the youths with the whole "it's like email" analogy, but "it's like the printing press" should be a lot more relatable. 😉

2025-09-27 03:01:06 UTC

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The other article I pointed to elsewhere in this discussion invoking negative mass particles to explain cosmological observations references a paper by Bondi in Rev. Mod. Phys.
http://ayuba.fr/pdf/bondi1957.pdf
I only took a cursory look, but it seems to construct a Weyl metric from a gravitational potential function, which has opposite sign for the "negative" mass. While he doesn't explicitly address the stress-energy tensor, and I haven't tried to calculate it, I would guess that implies a particle with negative rest energy.
@npub1hy7…0nqq

2025-09-21 18:26:02 UTC

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I see. I guess I didn't remember enough of the little particle physics I do know to remember that only a finite number of interaction terms are physically allowed (i.e. that you can't keep introducing terms with higher powers or derivatives of the various fields into the Lagrangian).

2025-09-21 15:08:22 UTC

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Sorry, I never got very far in particle physics, so this is probably a very naive question, but what is the meaning of "complete" in this context? I would have assumed just "describing all physical phenomena," but it seems like maybe it's being used to mean something different.

2025-09-05 12:19:48 UTC

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Agreed. And that older paper sort of does the opposite, it introduces two strange new mechanisms at once!

2025-09-05 03:48:19 UTC

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Interestingly this put me in mind of a different paper I'd seen some time ago that also purported to explain dark energy via negative mass particles. It's been a long time since I read that and I have not yet looked very closely at the one @npub1glg…tqzy linked to, but I think the older paper I saw was more radical, proposing that negative mass particles would also pop into existence via the addition of a "creation term" to GR.
https://arxiv.org/abs/1712.07962

2025-08-27 01:24:07 UTC

A friend found a tab open in Safari on their iPhone that they had not (knowingly) opened and whose history indicated it had visited a succession of locations, including multiple web searches and several different websites (some related to the web searches, some not). What are the likely ways that this could have occurred? Could this indicate a larger problem?
My best guess is that a site they opened had ads from some ad network with malvertizing on it that opened the extra tab and caused it to visit the various locations, but I'm really not sure.
#infosec #security #malware #iOS #iPhone

2025-07-29 22:32:36 UTC

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I'm probably missing something important here, but I guess I would have thought they still have to be equal due to Łoś' theorem.

2025-07-28 00:30:32 UTC

It's been reported over the last couple years that the contents of push notifications were accessible by the mobile providers who ran the push notification services and were being subpoenaed by various governments (meaning they could also fall into the hands of other parties in the case of a breach).
I had read that mobile applications can take steps to protect the content of notifications (either encrypting them or making them nothing more than a "check the server" message to the application), but I have no idea how to figure out which applications may be protecting notifications. Do people try to keep lists of this (even incomplete ones)?
https://www.404media.co/apple-gave-governments-data-on-thousands-of-push-notifications/
#infosec #mobileDev #security

2025-07-21 13:11:47 UTC

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They're also quite light to carry and preternaturally quiet.

2025-07-08 05:34:21 UTC

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For a second I thought, "are we doing superluminal neutrinos *again*!?" But now I see this is just the previous instance I was aware of.
I was teaching a course in lab methods and data analysis at the time, and I used this as a running example of how to evaluate the agreement of experiment and theory, the role of systematic error, and the fact that you as a scientist should be the first and most dedicated skeptic of any apparently miraculous result you come up with.

2025-06-28 01:03:17 UTC

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@npub1n4n…6ax6 I've had pretty good luck with GrapheneOS so far (over 3 years as my only phone) . The Play Integrity thing can be an issue in principle if some app you depend on happens to block your phone based on it. In practice the only issue I've run into personally is with the Authy 2FA app. In that case I just switched to a different authenticator, which was an improvement anyway.
But other people have been bitten by it; we were discussing in another thread:
https://helvede.net/@m/114748864059804840

2025-06-05 19:01:23 UTC

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The stages of thought I went through reading this post:
1. Why do you need all that!? Just use the geodesic equation.
2. Oh, you mean a *non-infinitesimal* (and possibly charged) mass, so you have to worry about radiation reaction! Sounds interesting.
3. Wait...won't a massive point particle in GR (at least below a certain charge and angular momentum threshold) be a microscopic black hole?
https://media.mathstodon.xyz/media_attachments/files/114/632/283/581/761/566/original/9c5d78c8b56bcc52.mp4

2025-05-20 18:00:15 UTC

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Maybe @npub1kmx…xxhr will want to get in on this discussion.

2025-05-18 12:03:21 UTC

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Yes, that's true. I once had someone ask me to help refute Electric Universe/Plasma Cosmology nonsense (because they knew someone who believed it), but when I tried to look into the claims they were just incoherent. You could point to various statements that were baseless or implausible, but it wasn't really even clear enough to say what precisely was the claim to be refuted.

2025-05-18 11:44:18 UTC

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I know that they're inherently bad at math (because they're just spitting out sequences of tokens that are probable based on their training set), but I thought some had implemented a kludge where when the LLM recognizes a math problem it writes code to solve it (something it *can* do, to a degree) and runs the code to get the answer to the problem.

2025-05-18 11:31:39 UTC

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I know a common crackpot trope used to be "I have this revolutionary theory. I just need someone to do the math for me." I wonder if the LLMs have now gotten good enough at math to solve that problem for them.

2025-05-04 17:11:37 UTC

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Yeah that was the bit that also raised my eyebrows. Using power series and then truncating them is your big insight!?
Also notably lacking in the article were quotes from other researchers in the field not involved in the research.

2025-04-20 15:37:22 UTC

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Yes, I agree that if you're teaching a class or having a more in-depth discussion and have equipment at hand, you can go the empirical route (as @npub19xg…9xct also suggested). I guess I was thinking more about the context where you're speaking in brief (without props) and just trying to convey the most basic idea of what polarization is in a few sentences.

2025-04-19 16:48:27 UTC

I'm curious if anyone has found a good, succinct way to explain light polarization to someone who has no formal knowledge about electricity and magnetism.
I find this vexing, because polarization is conceptually pretty simple: it's just about the direction in which a transverse wave does the waving. So it's easy to explain if you're talking about, say, waves on a string. The problem is that what is doing the waving here, the electromagnetic field, isn't really familiar to most people (if they haven't taken some physics classes). I've tried before to give explanations that sort of talk around the "what exactly is doing the waving" angle, but then the explanation just sounds oddly vague or abstract.
I've also talked to other people who have had the same problem, so I suspect there just isn't a very good way, but maybe someone out there has come up with a particularly clever way to approach it.

2025-03-26 04:39:39 UTC

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Do these actually work on up-to-date iPhones? I know I've seen a lot of claims about tools to gain access to mobile devices that then turn out to only actually work on older OS versions (presumably old enough to have known exploits).

2025-03-07 17:01:02 UTC

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I guess the sneakers McGuffin didn't seem so absurd to me (modulo details about how you interface to specific systems/ciphers) mostly because I didn't think that they went into much detail about how it worked other than "advanced math".
In my head I guess I just figured you could imagine it could be as simple as an chip implementing a novel algorithm that solves discrete logarithms in polynomial time.

2025-02-22 23:58:15 UTC

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Now that's service! 😂

2025-02-22 23:50:02 UTC

So as an appropriately mathy post for my first post after migrating to Mathstodon: I was reading the Wikipedia article on PRNGs, and it talks about "a probability distribution on \( \left(\mathbb {R} ,{\mathfrak{B}}\right) \) (where \( \mathfrak{B} \) is the standard Borel set on the real line)." What is "the standard Borel set"? I'm guessing that they really mean the σ-algebra of Borel sets on the real line (which I might call "the standard collection of Borel sets"), or does this mean something else?