foven

Really very cool, I've been using meetup and the website is just absolutely trash so any alternative is very welcome

1. Less than historically still has a quite high baseline compared to after ULEZ - if it was more polluted, presumably the change seen here would be more dramatic.

2. Definitely kickstarted it, but we're looking at taking that impact and continuing it for some 5 years after covid ended now.

3. You can look at the ULEZ map and it really covers everything but the outer tube line suburbs [1].

5. The control group in Luton, presumably, has the same lifestyle changes - it's not that far away (about 30 miles), so it is as close as you can get to a one to one comparison, not accounting for the fact that Luton is likely to be more deprived than London (especially in the council estates, which have horrible reputations).

[1] - https://tfl.gov.uk/ruc-cdn/static/cms/images/ulezdetailedmap...

I've seen this concept of using LLM/AI/etc for high throughput discovery of materials so, so often in the past 5 or so years and yet there hasn't really been any impact as a result.

I think this is the first one that has actually taken the pain to say how many of the discovered materials are actually feasible which is a real step in the right direction. Probably worth keeping in mind the step beyond plausible synthesis which is the actual cost/effort of the material. There's not much point if you find out RuO2 would be better than SiO2, as an example, if Ru is orders of magnitude more expensive.

A challenge I think you'll run into is that I expect the biggest companies (e.g. IBM) will already be doing the part they need themselves. I heard tell of IBM in particular using ML to improve their own chips before LLMs came along, so I'd be shocked if these bigger companies weren't already doing this for their own problems. Also, if you aren't doing the experiments yourself, it's always going to be a challenge to find a partner to test things for you and this will probably be the major time sink.

These things are interesting but for the most part quite dull and very industry-facing. Just mash together a bunch of random elements and see if it improves the thing you want to optimize.

Which gene gives me a tutor to support me at the most critical point in my intellectual development?

The kids at private schools are specifically primed for every part of the application process, including the interview and interview questions in a way that state schools simply cannot. It does not matter how smart you are if your competition is able to practice in a way you cannot.

Honestly, when it comes to hacking things together with matplotlib I outsource all of my thinking to chatgpt to do the 80% of doc hunting that is honestly not worth it since everything in matplotlib is labelled inconsistently.

More to the point, when you write an article like this foretelling the doom of the american economy, why would you think you are able to brain drain any country? What stops the countries you are trying to drain from offering better incentives to stay?

This is not really as simple as just going through the permutations. What this is in practice is a triumph of instrumentation. Before this, no one has imaged altermagnetic domain structure. The behaviour of these materials is intrinsically linked to what happens in the micro- (or nano-) structure.

There are two challenging things here that makes this a discovery. One, making the material, which is extremely difficult to verify as altermagnetic due to the nature of measuring these materials. Two, the measurement, which combines two techniques to distinguish this as separate from antiferromagnetism.

It is a huge push forwards for the budding field since it provides a really nice way to go to a large-scale synchrotron with your altermagnet and study it in detail.

To add a bit more to this, it's really a new class of magnetism. Traditionally we might think of ordered magnetic materials as being one of two: ferromagnets, which is what you think of when you think of magnets, and antiferromagnets. Antiferromagnets locally order their magnetic moments antiparallel so any which way you measure it, you measure no magnetization.

The application is this: We would like to use ferromagnets and spin currents to make spin-electronic devices ("spintronic") where only the spin information is transferred without any large electrical currents. The goal of this is to save energy from Joule heating as spin can flow with significantly lower energy dissipation.

Ferromagnets run into a lot of problems: they have a stray field, so patterned elements will interact and interfere with each other that sets a limit on how dense each nanostructure can be. Antiferromagnets have a big problem: they are extraordinarily difficult to measure and that is a challenge to overcome.

So the benefit that altermagnetic materials presents is a clear union that tries to overcome the problems of both while retaining the strengths of both.

The exact definition of the ordering of an altermagnet is a bit subtle and it mostly comes from an understanding of how the electronic band structure is different as compared with normal antiferromagnets.

Ultimately they still live in the country. They have ties to it. Their assets and wealth may be tied up in the country which is difficult to extricate. And, most importantly, their friends, family and life are in that country. It is absurd to think that it is so easy for people to just pack up and leave a country.

I admit to not really being familiar with either, but it seems that this allows you to display comments alongside the paper in the browser, which is a very nice feature (and overall has a nicer coat of paint). At first blush, I find it a bit more difficult to figure out what the point of scirate is and how it should be used.

waste plastic can be recycled into waste graphene

Transparency I assume. I understand the admin likes free speech and maintains some transparency, to explain why content has been removed, and giving away your information is always a risk in legal issues.

The operator of the kiwifarms is himself a US citizen with a US business. It is an advertised fact that if a police force comes after or shuts him down with a legal reason, it will cease to exist and he himself has stated he wouldn't operate it out of any other country than the US.

Pirate bay and sci-hub get affected by copyright law more than anything else and, to the best of my knowledge, kiwifarms is protected by section 230 in that respect and has always complied with legitimate takedown requests.

You absolutely can, and as you can see in this paper it is absolutely do-able to measure the resistance of these materials. They measure an insulator with something on the order of 10^6 ohm m. For reference, copper has a resistivity of ~ 10^(-8) ohm m, so there are about 14 orders of magnitude of difference. This does make the contact resistance pretty negligible in this case too.

There are measurement configurations that can be used to eliminate contact resistance (such as a van der Pauw measurement). Resistance, and electrical measurement in general, is the true proof - the Meissner effect is secondary and more confusing as, since this paper shows, a small ferromagnetic phase can give rise to the same effects.

Groups that typically do resistivity measurements on regularly measure low-temperature resistivities on conducting materials of ~ 10s of micro Ohm m. So if you're measuring in this range on a conducting material and hitting the noise floor with a SHARP drop, that's a pretty big indicator of superconductivity (assuming you haven't just broken your contacts which is a concern when cooling things down). I'm not so familiar with PPMS systems, but I imagine it has some built in auto-adjust on the sensitivities to where you can be pretty confident your noise floor is below these values.

What is complicating the interpretation here is the log scale (and lack of conversion to resistivity): It is amplifying the impression of the noise below what they call Tc, and making it harder to interpret the approach of the material to the transition point. The behaviour at the approach to Tc also doesn't really look like a metal, which should scale as propto T, or a semiconductor which should increase with decreasing temperature. Possibly a result of it being some horrible mixed phase ceramic.

Something that I find hard to understand is why there is superconductivity without cooper pairs; granted my understanding is related to more traditional superconductors and I'm not really very knowledgeable about the cutting edge high-Tc stuff.

Can we stop promoting this ateapie loonie. Every post they made is so thick with narrative it is completely divorced from reality.

Not necessarily true. Complex compounds can be susceptible to oxidisation and generally decay and degrade over time.

Compared to recent controversial results claiming the exact same thing (actually, more restrictive than this claim), it's not insulting it is what you should expect. The recent situation with Dias this year[1] is now under investigation as a case of data fabrication and he didn't even claim to have ambient pressure.

Frankly there are too many details missing to trust them. They've fabricated a thin film but not characterized it. It is well known that the properties of a material change when you go from bulk to thin film with a big dependence on the thickness. They don't mention how the resistance of this thin film is measured - that's important for what artifacts you might expect to see in your measurements (van der Pauw vs Hall bar measurements are the standard but they don't mention using either). Without characterizing the thin film it's also difficult to know, chemically and structurally, what you are measuring. I don't see any data confirming the quality of the thin film. The way the data is presented is such that it can be misleading, showing I-V curves instead of resistance when you are really trying to say the resistance is what is changing. The first paper doesn't even mention the insulator-metal transition that is present in the second paper which is bizarre - this is important if you are also claiming a superconductor transition close by and you would expect some discussion of this behaviour.

All of these are things that, one would hope, will be picked up by the reviewers as low hanging fruit before even really delving into the detail of the theory they present.

Decades of experience alone should not be trusted. Anyone can make a mistake, and not all the authors can be present for every experiment.

[1] - https://www.nature.com/articles/d41586-023-02401-2

Glad to see a realistic take on HN. Endlessly frustrating to see people be like "this will be replicated in days". Yeah, sure, let every other lab just drop what they're doing, order all the reagents on express, do a thorough characterization making sure they understand the impurities and crystal phase, then perform good airtight measurements in a couple days. Crystal growth always has complications many times outside of your control - the most minor of things can cause ridiculous problems.

Especially when they admit to having phase impurities, and it's not really clear how they've gone from bulk sample to measurement sample (are they really measuring just the superconductor or the impurity phase?). Needs addressing, especially when the Cu2S phase impurity seems to have a phase transition of it's own at or around 370K (suspiciously close to where some of their Tc measurements are).

As I mentioned in my above post, they have really dodgy data. Ideally, with something like this, you would have collaborators to verify alongside you as joint co-authors. I think something people underestimate if how easy to replicate samples are - crystal growth is difficult, and impurities are important. It is unlikely anyone will produce exactly the same sample only something close based on the process they've given.

In realistic terms it seems they're grabbing for the prestige without the foundation of crossing their ts. Bad science like this shouldn't be encouraged. It's likely there's not very many groups growing the same material system so they have the time to spare. A paper like this wouldn't be on the arxiv at all if they were 100% sure because they would go straight for the nature publication and take the time to do more follow-up papers while they can.

Edit: to be clear as well, a lot of people are underestimating the time it takes to reproduce a growth even with a manuscript telling you how to do it. People always leave out steps and oversimplify. There is a lot of extra characterization that takes time to double check you have the right material that lines up with what they have here. Only the direct competitors actually already growing this material can do it in a few days.

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.

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?

Consider you are another researcher (not the one who has just published).

You may want to keep up to date with your field. This is good to do and it helps foster new ideas for now and for future proposals. There will be a selection of journals that are relevant to you and they will publish work that, generally, will be tiered by either the scope or impact of the journal. Journal A publishes a lot of papers you find very insightful or useful, journal B publishes some work that is good to know but not profound. If you have maybe 20 minutes, maybe you will read one paper that catches your eye from Journal A.

The truest metric of how good the work you do is, at a surface level, is how well cited it is. How much do people read it, and then do they care once they put it down. It is not necessarily the case that putting your paper in a high impact journal gets a lot of citations, but its a lot of exposure and it maximises those chances.

As far as I am aware, they don't necessarily even do the final editing themselves; at least with the APS journals, they outsource the final typesetting to another company.

I think it is ridiculous to make such a sweeping statement about all of science when there is so much involved in each sub-field of science that brings its own problems to productivity and output.

Take for instance the fact that nobody in Europe seems to want to do a PhD anymore and nobody in America wants to do a post-doc (based on my experience speaking to colleagues looking for both things in the respective places). That means very often you have to settle for what you get and what you get is not necessarily the best people.

With regards to things being less disruptive, there are two issues here. One, the big papers that get published in i.e. Nature usually have extremely difficult techniques involved; something like low-temperature magnetic force microscopy that only a few research groups will have. This gatekeeps replication and further progression behind these few groups with these expensive piece of kit, so most people won't even care that it's happened. The other point I'd bring up is that a lot of research at the moment is not directly relevant to industry (so patents aren't quite as useful). Researchers are making absolutely insane devices to chase higher impact papers and patents that are so far ahead of where current industrial research is and wants to be that they're not going to adopt it easily at all.

All this is to say that more funding is great (always) but I don't buy what the author is saying about a strong-link problem at all. To me this just puts the idea of Nature = good science into people's heads and encourages bad research. The process of good science is incremental steps towards a shared goal, and lots of reports on the way there that tip off other people and help build a bigger picture.

No, the funding body specifies that all work has to be published as open-access. So if you publish without open access, you are getting yourself into trouble with the funding bodies which is a bad idea.