Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Superconductor news: What’s claimed, and how strong the evidence seems to be

science.org

Post reply on HN
Print view View original

151–160 of 501 posts

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#151

Post by IshKebab »

hughw wrote: post #131
mthomasmw wrote: post #88

Earlier quoted context omitted.

Do you have a link handy for "we don't know how bikes work" ?

e.g. What keeps bicycles balanced with or without a rider is still an active area of research, and even the seemingly basic idea that, for a bicycle to be self-stable, it needs to turn the handlebars into the fall, has not yet been proven. [*] https://ciechanow.ski/bicycle/

"Active area of research" is quite different to "we don't know how they work".

We know how they work. We might not have fully characterised the stability conditions, but that's not the same thing.

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#152

Post by foven »

carabiner wrote: post #92

Researcher on reddit thinks it's probably spurious measurement artifacts, not superconductivity: > I would say they are not faking it, but instead they just don’t understand what they are looking at. Based on what measurements they are doing, as well as how they are doing them, they do not have a good understanding of the standard processes to characterise a superconductor. Also, based on their analysis/discussion, t…

Agreed, this looks bogus. Some suspicious points:

In the first paper, they claim to measure zero resistance (on a scale of microvolts), but are very careful not to show full RvT curves - in the second paper, we can still see significant changes below Tc where they include more complete curves. How can the resistance change significantly in the superconducting (zero resistance) state? We can actually see significant noise in paper 1 fig. 1c in the ohmic state and it even appears to behave as an insulator at 0 field (increasing resistance with decreasing temperature), but a metal with applied field. There's something wrong with the measurement.

400 K is an odd choice for your superconducting temperature, and just so happens to be the top end of what an MPMS system can measure so is not completely random. Surely it makes sense to measure significantly above this with one of the oven attachments, verify these results with collaborators at other labs even.

10 Gauss is an extremely small field to use for a ZFC-FC measurement and again if their superconducting Tc is at or above 400K they need higher temperature data to show anything about the phase transition.

The claim that they have measured the density of states is completely unjustified - not even a citation. I don't know how you can believe that to be the case.

And in general the presentation both of the data and the paper itself is poor - if you just made a groundbreaking discovery like this, wouldn't you care?

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#153

Post by LargeTomato »

carabiner wrote: post #92

Researcher on reddit thinks it's probably spurious measurement artifacts, not superconductivity: > I would say they are not faking it, but instead they just don’t understand what they are looking at. Based on what measurements they are doing, as well as how they are doing them, they do not have a good understanding of the standard processes to characterise a superconductor. Also, based on their analysis/discussion, t…

>I would say they are not faking it, but instead they just don’t understand what they are looking at

What? How do they get funding and lab space if they can't read their own measurements? Something is fishy here.

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#154

Post by amelius »

hovering_nox wrote: post #82
scarmig wrote: post #74

Earlier quoted context omitted.

Most power loss in a computer comes from MOSFETs, not resistive loss. Which isn't to say that RTP superconductors wouldn't open up wild new possibilities. ETA: wrong

Much of the power consumed, and heat dissipated, by conventional processors comes from moving information between logic elements rather than the actual logic operations. Because superconductors have zero electrical resistance, little energy is required to move bits within the processor. https://en.wikipedia.org/wiki/Superconducting_computing#Fund...

Incorrect.

https://www.ti.com/lit/an/scaa035b/scaa035b.pdf

This document explains it well. (The resistance of the interconnect is not even mentioned as a significant component of power consumption.)

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#155

Post by iceflinger »

"this stuff is claimed to superconduct all the way up to room temperature and indeed up past the boiling point of water. Its critical temperature is said to be 127C"

Would this have implications about possible efficient methods of converting heat back into electricity? Or even just more ways of harnessing heat energy in general. I'm imagining heat pumps built with superconductors could be a critical part of mitigating climate change, but I'm far from a scientist and barely understand the physics here.

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#156

Post by mhh__ »

macromaniac wrote: post #117
carabiner wrote: post #92

Researcher on reddit thinks it's probably spurious measurement artifacts, not superconductivity: > I would say they are not faking it, but instead they just don’t understand what they are looking at. Based on what measurements they are doing, as well as how they are doing them, they do not have a good understanding of the standard processes to characterise a superconductor. Also, based on their analysis/discussion, t…

He doesn't provide an actual counterargument,he just says he doesn't like the data without explaining why. His earlier comment that graphite can do the same thing is untrue afaict. Graphite can repel the magnetic field but it would slide off, this is why in diamagnetic experiments multiple magnets are used to keep it in place. In the video it doesnt seem to be sliding anywhere, so imo the video is not showing diamagn…

Intuition shouldn't be considered harmful.

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#157

Post by foven »

gene-h wrote: post #109
jonplackett wrote: post #11

If this material does just what they say it does, what would it revolutionise? Or as the article talks about, is this just a pointer at other possibilities that would be the real game changers?

As far as I can tell the critical field, the maximum magnetic field it can withstand before turning into a regular conductor, is relatively low at 0.3 Tesla. In superconductors like YBCO, it's often more than 100 T. If critical field cannot be increased this will limit applications. Near term may be useful for devices which take advantage of quantum effects such as Superconducting QUantum interference devices or SQUI…

0.3 T is pretty insignificant for everyday use - you need some pretty big coils carrying around 10 A to produce that sort of field. For something like this, the benefit would be in just making wires out of it for driving currents without loss of power (no resistance, no heating). Think big bulky overhead wires - but it's all moot if the material isn't a superconductor.

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#158

Post by scythe »

littlestymaar wrote: post #146
bluGill wrote: post #101

Earlier quoted context omitted.

That depends. If it super conducts, but it isn't useful in the real world, then we will be waiting for theory to - hopefully - give us some insight into how to improve things to useful. This only can carry a small amount of current. I'm not sure how to figure out what small means (numbers are given in the article if you know how to use them!), but if the losses using regular wire are less than the energy needed to ma…

> This is made out of lead. Even if it is useful for transmission, the difficulty of working safely with lead in a factory may mean it is impractical. Or it make leach lead into the real world making it not safe to deploy. Lead is still routinely used in many applications today, either in metallic form, from ICE car batteries, to fishing or hunting gear, or as chemical compound in different kinds of glass. And the sa…

In particular, lead is still extremely common in radiation shielding, possibly because the drop in demand for other applications made it so cheap. Lead-lined drywall is the default approach for setting up a radiography, fluoroscopy or CT suite.

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#159

Post by mikeyouse »

LargeTomato wrote: post #153
carabiner wrote: post #92

Researcher on reddit thinks it's probably spurious measurement artifacts, not superconductivity: > I would say they are not faking it, but instead they just don’t understand what they are looking at. Based on what measurements they are doing, as well as how they are doing them, they do not have a good understanding of the standard processes to characterise a superconductor. Also, based on their analysis/discussion, t…

>I would say they are not faking it, but instead they just don’t understand what they are looking at What? How do they get funding and lab space if they can't read their own measurements? Something is fishy here.

From what I understand, this group wasn't actually funded to look for superconductors but instead for materials to aid in quantum nanoscience - so the claim isn't that they don't know how to read their instruments but rather that they aren't well-versed enough in superconductor research to appropriately design/test for the phenomenon.

Re: Superconductor news: What’s claimed, and how strong the evidence seems to be

#160

Post by konschubert »

seventytwo wrote: post #104
varjag wrote: post #49

Earlier quoted context omitted.

RoHS has a number of exceptions. Ambient temp/pressure superconductivity will absolutely be excepted too.

Nope, sorry. The EU is probably just gonna pass on RT superconductors. /s

I mean, they are trying to take a pass on AI... I wouldn't put it past us.
Post reply on HN