After the shenanigans from a few months ago, doubt
this post was submitted on 23 Dec 2023
205 points (96.4% liked)
Technology
59166 readers
2005 users here now
This is a most excellent place for technology news and articles.
Our Rules
- Follow the lemmy.world rules.
- Only tech related content.
- Be excellent to each another!
- Mod approved content bots can post up to 10 articles per day.
- Threads asking for personal tech support may be deleted.
- Politics threads may be removed.
- No memes allowed as posts, OK to post as comments.
- Only approved bots from the list below, to ask if your bot can be added please contact us.
- Check for duplicates before posting, duplicates may be removed
Approved Bots
founded 1 year ago
MODERATORS
Yeah I’ll get excited after it gets peer reviewed
It’s already been published. But it’s superconducting at 10 K. This is a new high temperature record, but pretty far from room temperature.
Yeah the headline makes you think it's even within "normal" temperatures, and then you see that it's like 10°C ~~below~~ above Absolute Zero.
Nitpicky but it's above absolute zero
Even if it was somehow 10° below absolute zero, it would still be 10° above absolute zero
I thought negative Kelvin were sometimes used to describe very very high temperatures but I could be wrong.
Thanks for the downvotes y'all, enjoy being wrong:
" Negative absolute temperatures (or negative Kelvin temperatures) are hotter than all positive temperatures - even hotter than infinite temperature."
Lmao I was kind of making a joke there, it's an absolute scale so a negative number can't actually exist, i.e. |-10| = 10
Additionally, temperatures expressed as negative Kelvin aren't actually negative Kelvin in reality ("reality" meaning the actual physical existence in our material world) because, as you pointed out, the material would actually be more temperate. Negative Kelvin is useful to represent systems where adding energy decreases the entropy of the system, rather than the standard of increasing entropy, but to relate it to the actual heat or energy of the material gets murky.
That's not what an absolute scale is tho. It's just because of the second law of thermo. -10 K would never be 10 K (maybe that's the joke? I don't get it. Maybe it was intended as an absolute/absolute pun). Either way, to me did not make sense.
Further, based on this article it seems rather correct to tie negative Kelvin to actual temperatures, especially considering it's been experimentally achieved...
What makes you say that isn't what an absolute scale is? It definitely is what an absolute scale is. For example, distance is measured on an absolute scale. Negative ten meters would be equal to positive ten meters. In the classic definition of temperature measuring the total kinetic energy of matter, a negative temperature would be equivalent to a positive temperature, as it is measuring how much the particles are moving. Similar to velocity (also an absolute scale), if a particle is moving at a particular speed, X, then moving at that same speed backwards would be -X, but it is still the same speed.
Negative temperatures are used to express something different from the classic definition of temperature, because the particles are not doing less than zero movement. Once a particle reaches absolute zero, it cannot move any less, but it can still have other properties that are directly tied to temperature change. Therefore, if purely expressing the classic definition of temperature, a negative temperature cannot exist, so any negative temperature would necessarily have to be equivalent to the same positive temperature. Of course, in any actual scientific conversation, the classic definition of temperature would be understood to be inadequate.
Go read the article. Temperature is dependent on all energy, not just kinetic. You're very sure of yourself for somebody so incredibly incorrect.
Maybe you should go read the article and actually read my comment. The article literally agrees with everything I said within the first few paragraphs. Negative temperatures do not and cannot exist under the classical definition, but the overall state of a system can reach a configuration that behaves like a negative temperature would, yet this is achieved by raising the temperature above what would tend towards infinity. Once again, it can be useful to represent certain configurations of systems of matter as a negative temperature with added context, and that's why negative temperatures are a thing in science. It's also why there are things like the summation of all natural numbers (1+2+3+4+...) being equal to -1/12. If you actually add up the natural numbers you get infinity, but ignoring that can yield useful results.
You are also absolutely wrong about temperature being dependent on all energy. Temperature is literally defined as the measurement of kinetic energy in a system. Are you actually suggesting that if I put an apple on an elevator, it's temperature is going to be increased when I send it up? Or that if I inject that apple with cold diesel fuel it will heat up? Those things would increase the energy of the apple, but not increase the kinetic energy and therefore the temperature does not rise.
From the article (which you clearly either didn't read or didn't understand):
"Temperature, however, relates not only to kinetic energy, but to the total energy of the particles, which in this case includes interaction and potential energy."
“The inverted Boltzmann distribution is the hallmark of negative absolute temperature; and this is what we have achieved,” says Ulrich Schneider. “Yet the gas is not colder than zero kelvin, but hotter,” as the physicist explains: “It is even hotter than at any positive temperature – the temperature scale simply does not end at infinity, but jumps to negative values instead.”
"At first sight it may sound strange that a negative absolute temperature is hotter than a positive one. This is simply a consequence of the historic definition of absolute temperature, however; if it were defined differently, this apparent contradiction would not exist."
"Temperature, however, relates not only to kinetic energy, but to the total energy of the particles, which in this case includes interaction and potential energy. The system of the Munich and Garching researchers also sets a limit to both of these. The physicists then take the atoms to this upper boundary of the total energy – thus realising a negative temperature, at minus a few billionths of a kelvin."
Again, very sure of yourself for being so incredibly incorrect...
Lmao you are the one who is actually tangibly misunderstanding the article. It clearly states that temperature RELATES to all forms of energy, which is true, but temperature is not directly affected by potential energy. Potential energy can, for example, raise the boiling point of a substance, but it does not actually change the temperature directly.
Since you clearly need a refresher on the fundamentals of heat and temperature:
https://www.houstonisd.org/cms/lib2/TX01001591/Centricity/Domain/5364/Thermal%20Energy.pdf
Yeah what happened to that one out of South Korea?
I forgot about that one.
superconducting below 10K or -263C. a record but by no means room temperature.
Loads of things superconduct below 10K - aluminium for one. This is for a different type of superconductor that can be turned on and off with a magnetic field.
Not quite in the usable temp for engineering yet but definitely on the right path. And a wee bit less sketchy than the last one. That combine with the progress is fusion reactors. We have a bright future in energy ahead of us (but pretty grim everywhere else)
Very cool, I didn't know a toggleable superconductor was even possible. With all this research into superconductivity it's only a matter of time before a room-temperature superconductor is found.
doped EuFe2As2