pglpm

joined 2 years ago
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[–] pglpm@lemmy.ca 1 points 6 months ago

The question of what an electron really is, is still open as far as I know. Even the question of whether it's a "particle", is still open. In many or most theories the question of "what it is" is somewhat bypassed. In quantum field theory you describe electrons as a field (like the electromagnetic field), but all fields have the peculiar property that they show energy exchanges in very localized, point-like regions of space – that's why you can think of them as particles sometimes. Take a look at Wald's book to get an idea.

There are even still open theories that try to describe electrons as mini charged black holes; not to speak about strings, and so on...

[–] pglpm@lemmy.ca 40 points 6 months ago* (last edited 6 months ago) (8 children)

The usual misleading sensationalistic title. It isn't the "shape of the electron" at all. A less misleading – but still not quite correct – explanation is that they have determined the statistical distribution of electron quantum states in a material. Very roughly speaking, it tells us where we're more or less likely to find an electron in the material, and in what kind of state. Somewhat very distantly like a population density graph on a geographical map. Determining such a population density doesn't mean "revealing the shape of a person".

The paper can also be found on arXiv. What they determine is the so-called quantum geometric tensor. I find the paper's abstract also misleading:

The Quantum Geometric Tensor (QGT) is a central physical object...

but it's a statistical object more than a "physical" one.

It's a very neat and important study, and I don't understand the need to be so misleading about it :(

[–] pglpm@lemmy.ca 3 points 6 months ago

Cheers! for some reason my search didn't bring that up!

[–] pglpm@lemmy.ca 1 points 6 months ago

Unfortunately they cannot yet be resized on the fly, as instead some vertical-tab extensions allow you to do. But it's a step in the right direction!

[–] pglpm@lemmy.ca 2 points 6 months ago

Cheers! 🙏 Unfortunately it's the same as on Sci-Hub, the "accepted version". It'll have to do.

[–] pglpm@lemmy.ca 1 points 6 months ago

Restored! Maybe worth a post update?

[–] pglpm@lemmy.ca 5 points 7 months ago (1 children)

It's just part of a player's roleplay.

[–] pglpm@lemmy.ca 32 points 7 months ago* (last edited 7 months ago) (3 children)

"Ethical and legal objections". The point in this case is that what's legal is unethical, and what's ethical is illegal. Analogous to other situations through history and countries, for example in the USA when it was illegal for black people to sit in certain parts of a bus, or in Germany when marriage with Jewish people was illegal.

As human beings, it's always important to make the ethical choice.

[–] pglpm@lemmy.ca 1 points 8 months ago

I'm actually a physics teacher 😂 In fact, as I write in the post, these questions are more about self-reflection. They bring to light some interesting points or issues about Newtonian mechanics and the way we teach it.

Please see my replies in the cross-post https://lemmy.ca/post/33867210

[–] pglpm@lemmy.ca 1 points 8 months ago* (last edited 8 months ago)

Completely agree, which I think is very interesting. In Newtonian mechanics, some scalar and vector quantities such as mass, internal energy, contact forces (stress), heat flux are frame-indifferent. Others, such as velocity and acceleration, are frame-dependent but we do have transformation rules for them. Some quantities – and quite important ones – such as momentum, are in a sort of limbo: they are frame-dependent, but there's no clear transformation rule for them.

From the point of view of relativity theory, it's interesting to note that for this particular case of coordinate transformation – note that it is not a Lorentz boost – we can actually calculate the spatial components of momentum in the new coordinate system, if the reported momentum is expressed as a covariant vector (p_µ). This is because its unknown temporal component (energy) gets multiplied by zero in this transformation. But the text is ambiguous on whether the reported components are covariant or contravariant.

 

You can find it at /c/typography@lemmy.ca or !typography@lemmy.ca.

I was looking for such a kind of community to post a question, but a search in https://browse.feddit.de/ showed that no such community seems to exist as yet in the Fediverse. So why not creating one.

 

I'm often seeing links to posts on Mastodon and, when I click on them, they open in a Mastodon instance different from mine (I mean from the one where I have my account). This means that I cannot reply, boost, etc, that post.

The very roundaboundaboundabout way to solve this is to go to your instance and search/"explore" for that post.

Is there a smoother way to address this problem?

I found 1001 "beginner's guides for Mastodon" online and after reading 3 without finding any solution, I decided to ask here.

A similar problem existed with communities (and still exists with posts) in different Lemmy instances, but luckily tools like the Lemmy Instance Assistant solve this rather smoothly with a click.

PS: sorry if this sounds like a rant – it isn't. Just asking for info. I'm sure problems like this will eventually be solved in the Fediverse :)

 
 
 

cross-posted from: https://lemmy.ca/post/1916423

This insightful blog post seems to refer to this article. I hope the article is an isolated case. Although it's undeniable that scientific illiteracy is spreading.

 

cross-posted from: https://lemmy.ca/post/1916492

cross-posted from: https://lemmy.ca/post/1916423

This insightful blog post seems to refer to this article. I hope the article is an isolated case. Although it's undeniable that scientific illiteracy is spreading.

 

cross-posted from: https://lemmy.ca/post/1916423

This insightful blog post seems to refer to this article. I hope the article is an isolated case. Although it's undeniable that scientific illiteracy is spreading.

 

cross-posted from: https://lemmy.ca/post/1916423

This insightful blog post seems to refer to this article. I hope the article is an isolated case. Although it's undeniable that scientific illiteracy is spreading.

 

This insightful blog post seems to refer to this article. I hope the article is an isolated case. Although it's undeniable that scientific illiteracy is spreading.

1
submitted 2 years ago* (last edited 2 years ago) by pglpm@lemmy.ca to c/busterkeaton@lemmy.ca
 

There's an old youtube channel by "Avamogal" (apparently "a mom to 7 boys. 10 grandkids 8 boys, 2 girls") which is full of great collages of Buster clips, with interesting music backgrounds. Recommended.

Sadly it seems the channel hasn't been active for 6 years or so...

 

I have read the FAQ of KDE Neon: it is well made and answers ground questions like "Is it a distro?" or "Can I turn Kubuntu into KDE Neon?"

...And yet I'm confused, because I'm just a newbie in the Linux world. For instance, when they say "on top of a stable base" I don't know what's meant as a "base".

I think I understand that it isn't a distro, but it fascinates me that it's meant to be installed from an ISO or similar, just like a distro.

I wonder if any of you can explain:

  • What is it, in different words?
  • Why is it "implemented" as it is?
  • Are there any other "quasi-distros" like KDE Neon out there?
  • Do you use it? how has your experience with it been?

Cheers!

 

If I want to link to a community X on a Lemmy instance Y.zzz, I know I should use the link /c/X@Y.zzz, which will redirect to the copy of the instance on the server where the user has the account.

What is the analogous way to link to a post? For example this post has address lemmy.ca/post/1866360 but what link should I give to users on another instance, so that they can see the post in their instance?

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