I am seeing a lot of newcomers lately to the room-temperature superconductor rodeo.
They might not be aware of the long history of these events, and I think there’s some cross-cultural communications difficulties going on because of that.
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There’s no reason (that we know) that a room-temperature superconductor can’t exist.
But we also don’t know how to make one by design.
It almost certainly won’t superconduct by a “conventional” (i.e. phonon-mediated BCS) mechanism.
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So it’ll be a serendipitous discovery in some unexpected strange material.
But not every serendipitously discovered unexpected apparent very low resistance state in a strange material is superconductivity!
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You’d think superconductivity would be easy to detect; it comes with zero electrical resistance, so if you measure resistance, and it’s zero, you’re done. Unfortunately there are many ways to get fooled (too many for one thread!)
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So generally you’ll see multiple pieces of evidence for superconductivity in a new report: Meissner effect, AC susceptibility, temperature-dependent critical field and critical current, single-particle tunnelling gap, jump in specific heat at T_c, Josephson tunnelling...
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... AC Josephson effect, etc. (Probably not all of these in one paper, but usually at least a couple in addition to zero resistance.)
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Even then, nature sometimes throws good scientists a curve ball, and can fool on multiple counts. So there is a steady trickle of difficult-to-explain results that look a lot like superconductivity, sometimes at unexpectedly high temperatures.
“Tantalizing” is often used.
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These are colloquially called Unidentified Superconducting Objects.
(I’ve heard a few scientists credited with originating that phrase; Bob Cava credits Koichi Kitazawa in the linked paper).
sciencedirect.com/science/articl
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![](data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="113" height="150"><rect fill-opacity="0"/></svg>)
Just a few examples (the ones I could think of off the top of my head – I am sure every condensed matter physicist has their favourites!)
1) palladium hydride
sciencedirect.com/science/articl
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2) multi-walled carbon nanotubes
arxiv.org/abs/cond-mat/0
3) doped graphite
onlinelibrary.wiley.com/doi/10.1002/ad
4) silver nanoparticles in a gold matrix
arxiv.org/abs/1807.08572
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![arXiv logo](data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="360" height="360"><rect fill-opacity="0"/></svg>)
The last one comes with a nice video showing diamagnetism at room temperature!
youtube.com/watch?v=G-aoR8
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![](data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="360" height="270"><rect fill-opacity="0"/></svg>)
youtube.com
Giant Diamagnetism in Au-Ag Nanostructures at Ambient Conditions
Engineered Au-Ag nanostructures show giant diamagnetism and vanishing resistance under ambient conditions. This video shows the repulsion of aggregates of Au...
There are also some more scandalous cases where fraud was known to occur or strongly suspected. But AFAIK the examples above aren’t scandals*, and reputable scientists were involved.
*Some may disagree. Let’s just say that there are probably many genuine reports out there.
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Also notable is that there’s no clear end to each of these stories; in many cases if you look into these past examples, you’ll find them just as credible as the most recent example. It’s just that, after a while, with no news of experimental replications in other labs...
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...interest fizzles out.
Unfortunately many mysteries in science remain unsolved!
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New superconductors *are* discovered of course, sometimes w/ unexpectedly high (but well below RT) transitions, in unexpected places (doped C60, MgB2, and pnictides are a few during my career). For these, experimental replications are numerous and they're widely accepted.
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I hope this goes some way towards explaining how people in the field view reports of superconductivity at unexpected high temperatures. They are exciting! And worthy of discussion. They’re science, and they also inspire more great science...
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...trying to figure out if there’s really a new superconductor there, and how it might work.
But there’s also a healthy scepticism and a wait-and-see attitude among those who’ve been to the rodeo before.
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PS, in tweet 2, I should have specified that a room temperature *ambient pressure* superconductor almost certainly won't have a phonon-mediated BCS mechanism.
(It could happen at high pressure, though recent reports are also colourful.)
18/17
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Meissner effect or bust: Day 8.5
We made the rocks
0:09 / 1:21
The Huazhong University of Science and Technology (HUST), whose video of diamagnetism was circulating earlier, have put their results on the arXiv. This looks like the first independent lab to report strong diamagnetism in #LK99, suggesting the diamagnetism data is likely real.
![Image](data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="1152" height="545"><rect fill-opacity="0"/></svg>)
NEW: Hyun-Tak Kim (writer of the 6 author LK-99 Superconductor paper) has provided the New York Times with a new video showing the levitating LK-99 sample.
![](data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="1200" height="675"><rect fill-opacity="0"/></svg>)
new floaty rock video from an OG author
Q's from my brain 
- is it the same sample as they had shown before?
- what is the strength of the magnet / field
- what is the weight / what are the dimensions of the sample
- wonder if it can hold on sideways like that other (poorly… Show more
- is it the same sample as they had shown before?
- what is the strength of the magnet / field
- what is the weight / what are the dimensions of the sample
- wonder if it can hold on sideways like that other (poorly… Show moreQuote Tweet
![](data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="48" height="48"><rect fill-opacity="0"/></svg>)
Floates0x
@floates0x
NEW: Hyun-Tak Kim (writer of the 6 author LK-99 Superconductor paper) has provided the New York Times with a new video showing the levitating LK-99 sample.
0:10
Here's a statement that captures the annoying semiotics of what is going on with the LK-99.
news.ycombinator.com/item?id=369963
love that you can get these completely contradictory opinions from watching the exact same scenario
![Image](data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="1125" height="569"><rect fill-opacity="0"/></svg>)
![Image](data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="1125" height="608"><rect fill-opacity="0"/></svg>)
People who are saying "it's over" every time there's a lukewarm or conservative statement from a lab working on LK-99 have a bad model of academic research
A lot of the big university and state labs have an incentive to slowwalk this for a couple different reasons
A mass-produced room-temperature superconductor would only affect industries that use electricity.
It's so wild that we can "see" molecules now. Humans can do so many amazing things when we're not being miserable monsters to each other. I have hope tho.
![Image](data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="1164" height="712"><rect fill-opacity="0"/></svg>)
TED has been a disaster for the human race
Quote Tweet
Maria
@real1maria
"Why is it that 5 000 units of our currency is worth one unit of your currency, where we are the ones with the actual gold reserves? It's quite evident, in fact, that the aid is not coming from the west to Africa, but from Africa to the western world."
Mallence Bart-Williams
![](data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="73" height="73"><rect fill-opacity="0"/></svg>)
There are groups of people in Silicon Valley who end up turning a high level of self-promotion into failing executive role after failing executive role.
10 years of getting fired from extremely high-paying 9-12 month stints at company after company and retiring rich.
Wild.
if they make the rock float at a VC backed space factory company its completely over for tech critics. ZIRP vindicated; capital allocated correctly; masa san was just early; cathy wood greatest of all time; we will be a multiplanetary species and you WILL enjoy post-scarcity
In software engineering, there's what people think of as "docs" and then there's "the information I needed to debug that thing that took to days of my life."
The second thing is different and should be called something other than "documentation." But what should we call it?
So let me get this straight, GPT-4 has only been out like 6 months and we're already getting a soft landing, superconductors, fusion, and we're curing cancer? And people still think it's a stochastic parrot!
I can't stop staring at this chart
People have no idea how wild it's about to get
![Image](data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="1200" height="1108"><rect fill-opacity="0"/></svg>)
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Ajeya Cotra
@ajeya_cotra
Important article: time.com/6300942/ai-pro The single most important data point that suggests "progress is unlikely to slow in the next 2-3y": GPT-4 cost ~$100M (probably less), and Alphabet has 1000x that much money in cash on hand:
![Image](data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="500" height="500"><rect fill-opacity="0"/></svg>)
look, it's really easy. you log on and tweet "it's so over" or "we're so back" depending on any minor development in the current thing or if things are really crazy you tweet "it was so over but now we're so back". you can also post this meme with two astronauts...
![Image](data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="911" height="1200"><rect fill-opacity="0"/></svg>)
A new Chinese LK-99 replication effort found support for the Meissner effect at room temperature.
![Image](data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="991" height="575"><rect fill-opacity="0"/></svg>)
being optimistic reading the
about how tech financial
can raise the statements of
standard of living tech companies
![Image](data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="1200" height="556"><rect fill-opacity="0"/></svg>)
25 year old me: don't write code comments, just use clear naming
35 year old me:
![Image](data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="1200" height="896"><rect fill-opacity="0"/></svg>)
in my life so far I’ve seen
- smartphones
- confirmation of the Higgs boson
- reusable rockets
- superhuman Go AI
- detection of gravitational waves
- protein folding ~solved
- images of a black hole
- mRNA vaccines (at unprecedented speed)
- computer vision ~solved
- NLP ~solved
![Image](data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="1061" height="1200"><rect fill-opacity="0"/></svg>)