muhdeeb

So it seems that their definition of 100% means 1 excited state per incoming photon, and then they use a material that converts a single high energy excited state produced by one photon into 2 half as energetic excited states...but then they apply the definition that just counts any excited state per incoming photon to juice their numbers.

So more like 65% energy conversion efficiency at best.

How I wish more people would remember this! What extraordinary interpolation tools we have! Truly marvelous and worth celebrating, but not worth a damn for extrapolation. Such a torrent of well-formed advertising trying to convince experts that a universal and reliable extrapolator has been demonstrated!

The reason this is important is not because the molecule has any practical utility, either now or in the future. Most of the reactions it participates in will probably be various decompositions of itself into other. The real importance comes from what this molecule can teach us about the laws of nature--why Si is the way it is, so distinct from carbon. Specifically, how do the valence electrons of Si manage in a 5 member ring? What does that wave-function look like, and does it agree with our predictions? Do we understand this corner of the universe as well as we think we do? Orbitals are tricky things to compute, so we need difficult to construct molecules to test our calculations.

Huh. That's an interesting possible metric. How many competing tendencies in a space? It a good question and one that's been asked before.

I wonder how machine learnability compares to other measures of chaotic structure, like multi-fractal approaches etc. I wouldn't be that surprised if it's accidentally the same or quite similar to some of the existing metrics.

Well put!

You make a very good point. The historical trajectory of a field's development is an extremely haphazard presentation of the ideas. It belongs in a separate curriculum, and I'm grateful that the history of science exists as field for that purpose. It's nice to study the history after one has understood the material; that way we can see what ideas prospered and faltered, and what might be ready for reinterrogation.

Why should we study antiquated and easily falsifiable models before we get to our modern and less-easily falsifiable models?

Drawing on common intro chemistry: the plum-pudding model of the atom is cute in historical context, but a real distraction from what our best understanding of what atoms are, for which we have much better evidence than the helium-nucleus scattering experiment that first suggested a dense, charged nucleus in gold atoms. We really only need the old plum pudding as a counter example, yet fail to explain the experiment in enough detail to justify including it. What probably began as a fastidious attempt to provide full context to a landmark experiment has at this point completely degenerated into historical trivia about the structure of British desserts, and yet remains prominent in educational material.

Math is a bit better off in this respect.

In this case, chemistry of Ga and Ge are a bit different, and the Cr compound that was misstated is part of a family of materials that rely heavily on the coordinating chemistry of Ge and its mates in the same period. So it makes more sense. If indeed it were Ga, that would be an interesting compound that probably wouldn't look anything like the material families being discussed by these authors.

I think the reader and the writer share the burden of accurate communication. The reader should ideally come prepared and the writer should provide as best they can. A prepared reader makes quick work of this typo.

I'm inclined to give them a pass. It's easy enough to figure out that it should be germanium and not gadolinium, and dyslexia already exists among scientists. Context provides enough information to correct the record.

I didn't catch the error the first time around because I autocorrected to Ge--there are only so many anions that can make that formula work and staring at these formulas all day long can make you go cross eyed anyway.

What I think is more dangerous to understanding is skipping formulas in favor of initials! BFO instead of BiFeO3, or BT instead of Bi2Te3, SRO for SrRuO3, LSFO for La0.3Sr0.7FeO3 abbreviations that I think obscure too much detail. You can more easily wander into talking about different things with the same terms. Such abbreviations are already endemic in condensed matter physics.

The trouble with holograms, if I understand them correctly, is that when storing information in a phase structure, to change one small part of the information you are storing, the hologram must be adjusted everywhere. The bits are encoded in a way that’s a bit nonlocal. I think a reasonable analogy is how small changes to a structure affect its Fourier transform. The whole thing leaps in Fourier space for a little wiggle in direct space. I foresee that being troublesome for write operations.

This article has a headline engineered with shock value connotations, but when you read it carefully, it takes pains to rein the suggestions of the title in as much as possible while still stirring the pot. It’s a kind of artistry you need to get papers published these days.

All that aside, it’s an interesting thing to think about but it’s not a basis for any kind of personal health recommendation and the authors state that. I have relevant expertise and this is a very complicated area that people routinely want to be boiled down into black and white simple advice. What this article seems to say is that lotion can affect the oxidation chemistry nearby it, but it’s not yet known if that is an effect with consequences that are on the whole negative or positive.

I would criticize the authors for their use of the word disrupt, because of the negative connotation carried by that word when talking about human biological systems. They use a softer, more neutral word, perturb, to express the same idea later in the article, which I think better expresses the idea without an emotional tinge to it.

Agreed! It’s pretty alien. I’ve seen brilliant single author work, but nothing that uses “I” unless it’s a blog post. The formal papers are always the singular “we”. Feels very communal that way!

Nice to include the giants we stand on as implied coauthors.

What’s the plan for dealing with cosmic rays? I worry about when your beautiful angstrom-precision qubit networks encounter a relativistic proton or muon.

As far as I understand it, smaller scale XFEL devices still suffer from poor aim, even though now these machines have been miniaturized to basement scales. They don’t need to be significant fractions of a kilometer anymore. This aim issue will probably be solved in the next few years. It’s an exciting time to be in X ray science, particularly anything ultrafast.

It’s a cadmium isotope. Super cool technique, I think perturbed angular correlation.

https://en.m.wikipedia.org/wiki/Perturbed_angular_correlatio...

I haven’t used it for my research, but it’s an incredible local probe of electric and magnetic fields in materials. There’s no other technique that I’m aware of that smuggles information about the chemical structure of a single coordination sphere into such clean, distinct emissions. The brief excited state of the isotope after the first emission event and before the second is sensitive to practically everything. It all shows up in the deconvoluted spectra.

Shame nearly all the isotopes that work for this are not ones that are super interesting for modern quantum materials. Perhaps that will change out of necessity.