Nostr notes by Weekend Editor

"We are all agreed that your theory is crazy. The question ...

2026-10-27T16:34:29Z

In reply to nevent1q…3t6f
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"We are all agreed that your theory is crazy. The question that divides us is whether it is crazy enough to have a chance of being correct."

-- Niels Bohr to Wolfgang Pauli after a presentation on nonlinear quantum field theory, as reported by Freeman Dyson

https://en.wikiquote.org/wiki/Niels_Bohr#:~:text=35-,We%20are%20all%20agreed%20that%20your%20theory%20is%20crazy%2E%20The%20question%20that%20divides%20us%20is%20whether%20it%20is%20crazy%20enough%20to%20have%20a%20chance%20of%20being%20correct

Once I was hired into a job and noticed they were being extra ...

2026-10-27T00:42:45Z

In reply to nevent1q…nlu7
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Once I was hired into a job and noticed they were being extra special slow about putting a whiteboard in my office. So I began to use whiteboard markers & erasers on the window glass, which pretty much works.

Managers, always superstitious about corporate secrets, were convinced someone could read this writing from outside, on a 7th floor window, *backwards*.

That got the whiteboard installed just a couple days later.

So don't underestimate the utility of writing on windows as a way of "managing upwards"!

I'm intrigued by the phrase "cut it into a stone on this ...

2026-10-16T16:59:19Z

In reply to nevent1q…97nj
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I'm intrigued by the phrase "cut it into a stone on this bridge".

A pocket knife to carve into wood, I can understand.

But who goes out for a walk with the spouse to an academic meeting with stone-cutting tools in the pockets?

With a few notable exceptions, one does not associate math with ...

2026-10-04T13:03:00Z

In reply to nevent1q…9wtw
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With a few notable exceptions, one does not associate math with Victorian women. So it's delightful to see some actual math under the Victorian subtitle "The Ladie'
s' Diary".

But... I note all the solutions were, alas, submitted by men?

A blog post about, among other things, the placement of ALPRs ...

2026-09-28T22:14:24Z

In reply to nevent1q…85up
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A blog post about, among other things, the placement of ALPRs (automated license plate readers like Flock) in suburban Boston.

Tufts University has, for no particularly obvious reason, surrounded itself with cameras.

The CEO of Flock, in a Forbes interview, described the group with the camera locations as one of several "terroristic organizations".

https://www.someweekendreading.blog/tufts-flock/

Possibly a very, very smart cat.

2026-09-28T14:15:25Z

In reply to nevent1q…tv0l
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Possibly a very, very smart cat.

"interesting group of fae" does NOT sound innocent, even ...

2026-09-13T15:21:13Z

In reply to nevent1q…ng49
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"interesting group of fae" does NOT sound innocent, even from its context untimely ripped. :-)

All the more impressive, given that atmospheric O2 content 1.2Gya ...

2026-09-10T20:57:08Z

In reply to nevent1q…djrj
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All the more impressive, given that atmospheric O2 content 1.2Gya was quite limited, maybe 0.05 atm partial pressure vs 0.2 today.

https://en.wikipedia.org/wiki/Geological_history_of_oxygen

Too bad nature hasn't cooperated, though. I remember Glashow ...

2026-08-09T13:07:04Z

In reply to nevent1q…q3yz
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Too bad nature hasn't cooperated, though.

I remember Glashow giving seminars at MIT in the mid-80s, still hoping someone would observe proton decay and thus vindicate (the simplest version of) SU(5).

Needs a brass head. Any prankster-sculptors available? ...

2026-07-02T20:28:57Z

In reply to nevent1q…k5u4
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Needs a brass head. Any prankster-sculptors available?

https://en.wikipedia.org/wiki/Brazen_head

I was a grad student at MIT, when Viki Weisskopf was still a ...

2026-06-11T03:41:22Z

In reply to nevent1q…skxl
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I was a grad student at MIT, when Viki Weisskopf was still a professor, though elderly.

He was invariably a gentleman, at least as far as I could observe.

An example:

Physics department colloquia were held in 26-100, a huge lecture hall, in those days. All the senior profs, particularly theorists, sat down front, stage left.

One day a visiting physicist giving the colloquium apologized for being so elementary, reminding us all of the basics of.... something or other.

Viki stood up and *interrupted*, something he *never* did. In his lovely Mittel-Europe accent, he shook his finger and grinned, saying: "Young man, you should never underestimate the pleasure of a physicist at being told something he already knows!"

Then he sat down, there was applause, and the talk went happily on from there.

In that case, quaternionic and octonionic field theory would make ...

2026-05-21T11:30:39Z

In reply to nevent1q…ygev
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In that case, quaternionic and octonionic field theory would make you totally incomprehensible.

(Though, to be fair, they do that to *everybody*.)

When I was starting out doing statistics in oncology ...

2026-04-28T18:57:48Z

In reply to nevent1q…y679
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When I was starting out doing statistics in oncology bioinfromatics, I had some gene expression data for cancer cells from which I was supposed to find gene patterns that indicated the onset of cell death (apoptosis).

Some of the genes that came up were the SNAP and SNARE families. Back in those days, they were annotated as neuro genes, making membrane vesicles for neurotransmitters and such. The first response of my biologist client was a rather rude one: "Get that neuro crap out of my data!"

Well.

It turns out they're also involved in "membrane blebbing", in which cell surface membranes make vesicles to eject cytoplasm, as a part of both cell division AND cell death by apoptosis. So "that neuro crap" was a set of genes involved in reshaping membranes, the result of which depends on if the cell is squirting neurotransmitters, dividing, or dying. Dying was the relevant context in that dataset.

Context matters!

I was polite, but it was with great satisfaction that I could eventually point this out to the rude biologist. :-)

https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/blebbing

I'm sure one can find military analysts with something to say ...

2026-04-13T21:03:00Z

In reply to nevent1q…t579
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I'm sure one can find military analysts with something to say about the kink in the line.

But:

(a) I'm too lazy :-( to wade through the word salad to figure out what their writings mean,

(b) the analysts who write in the open do so with unclassified data and are probably no better informed than the rest of us,

and

(c) it's most likely either increased Ukrainian use of drones or increased Russian use of human wave attacks, or both; anything else is likely to be a closely guarded secret by one side or the other.

In the meantime, on this subject I've frequently quoted Bertrand Russell:

"The mark of a civilized man is the capacity to read a column of numbers and weep."

(Nobody, including me, can find a source for him saying this, but I'm pretty certain he would have agreed with the sentiment.)

I've been building a regression model of (the Ukrainian ...

2026-04-13T20:36:36Z

In reply to nevent1q…nftk
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I've been building a regression model of (the Ukrainian reports of) Russian casualties over time.

It's a segmented regression model, i.e., a kink in the line, since on or about 2024-Feb-22, Ukraine got dramatically better at killing Russians.

https://www.someweekendreading.blog/ukraine-1300k/

From a couple years ago, on the unaffordability for the rest of ...

2026-04-04T17:38:01Z

In reply to nevent1q…nh6m
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From a couple years ago, on the unaffordability for the rest of us of keeping the rich around. GINI coefficients, class mobility vs wealth inequality, and so on.

https://www.someweekendreading.blog/unaffordable-rich/

Yes, Johnson really hit the jackpot here. For a very minimal ...

2026-04-03T01:12:16Z

In reply to nevent1q…e4lm
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Yes, Johnson really hit the jackpot here.

For a very minimal addition of external constraint in the form of bag boundary conditions, he got a phenomenological theory that suddenly let us calculate all sorts of things about hadrons. (As you can see the later sections of that paper!)

I asked him about it once, hoping to get a heroic story. He always looked like he just woke up from a nap, so he blinked owlishly, said something like: "Yeah, that was something me & the boys here whipped up one weekend." (Sure, Ken. Whatever you say.)

It's really very much like Mayer/Jensen/Wigner and the nuclear shell model (Nobel in 1963): introduce (and justify!) a fictitious harmonic oscillator potential to confine nucleons to the nucleus, and you get a phenomenological theory that suddenly hands you almost-correct nuclear energy levels.

Very cool stuff, making good phenomenological theories by the artful introduction of things like potentials and boundary conditions.

https://en.wikipedia.org/wiki/Nuclear_shell_model

The bag model is a really good example of how to make an ...

2026-04-02T01:50:55Z

In reply to nevent1q…vkun
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The bag model is a really good example of how to make an effective theory by imposing the bare minimum of constraints to match observation.

In this case, the bag *forces* the theory to give you confinement, and thus hadrons.

Ken Johnson did an amazing bit of work there, partly due to restraint in *not* attempting to jam in a lot of other things.

(He was pretty interesting to talk to, also.)

It's a nice metaphor, for sure. But metaphors, unlike ...

2026-04-01T00:11:47Z

In reply to nevent1q…3jsr
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It's a nice metaphor, for sure.

But metaphors, unlike mathematics, have to have enough explanatory words so that people get the right image.

A soap bubble, which is what I thought of when people said "bubble", is entirely wrong: it's a 2-layered bubble with a little soapy water between them, and both the inside and outside are air.

A steam bubble has just 1 layer, and the liquid is on the *outside*.

That's what I needed to hear; without it the metaphore was actively destructive to my understanding.

When I was in grad school, in QCD people always described hadrons ...

2026-03-31T23:57:46Z

In reply to nevent1q…5p29
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When I was in grad school, in QCD people always described hadrons (usually via the MIT bag model) as like steam bubbles.

That always confused me: I was thinking of a soap bubble, with "the stuff" inside and a vacuum (+ fluctuations) outside.

The reverse is what the metaphor meant: liquid water outside, gaseous steam inside the bubble. The virtual quarks are in a *condensate* outside, and in their excited gas-like phase inside.

So there's still a quark/anti-quark soup, but the condensate is outside and the inside is more like the quark/gluon plasma with a couple real quarks.

Thanks! They're disabled for now, until Microsoft re-enables ...

2026-03-26T17:50:18Z

In reply to nevent1q…g5rc
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Thanks!

They're disabled for now, until Microsoft re-enables them against my wishes.

Maybe I'll figure out how to move my blog to Codeberg by then.

I guess I never found the rounded end, then. :-)

2026-02-22T21:32:21Z

In reply to nevent1q…p36m
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I guess I never found the rounded end, then. :-)

More importantly, both of them sound like "Bourbaki".

2026-02-22T21:28:18Z

In reply to nevent1q…ddkc
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More importantly, both of them sound like "Bourbaki".

What's up with the bottom line suddenly crossing over the ...

2026-02-21T19:48:05Z

In reply to nevent1q…fq9d
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What's up with the bottom line suddenly crossing over the others at the right?

I retired in 2020, working then as an applied statistician. It ...

2026-02-16T02:19:49Z

In reply to nevent1q…74y4
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I retired in 2020, working then as an applied statistician.

It was *always* the hardest to get people to back down from "Can you calculate this stat for me?" to describing what they were actually trying to do. Almost always, the stat they thought they wanted was not the most appropriate one.

So, pretty similar.

Back in the day -- say, 1980 - 2000 when I did software -- the ...

2026-02-16T00:58:59Z

In reply to nevent1q…rlfn
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Back in the day -- say, 1980 - 2000 when I did software -- the hardest question to get answered was asking the client, "What are you REALLY trying to accomplish?"

Inspirational Skeletor is inspirational.

2026-02-11T15:54:50Z

In reply to nevent1q…3f08
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Inspirational Skeletor is inspirational.

Or maybe they finally read Dante's _Inferno_, and saw the ...

2026-01-31T16:26:57Z

In reply to nevent1q…x8xy
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Or maybe they finally read Dante's _Inferno_, and saw the description of deepest Hell as Cocytus, a frozen lake.

(Yeah, ok, probably not. But I can dream.)

https://en.wikipedia.org/wiki/Cocytus

RE: https://mamot.fr/@pluralistic/115983875604010038 Numbers ...

2026-01-31T14:33:47Z

RE: https://mamot.fr/@pluralistic/115983875604010038

Numbers don't lie.

They do, however, occasionally burn.
nostr:note1rqkuzgpqkvrfh4z7uk87r43npc0acg0zaqverh7tag3uwdry9eysgu6jl2

Doggerland gonna rise again!

2026-01-30T13:47:11Z

In reply to nevent1q…g3tn
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Doggerland gonna rise again!

(This reply has nothing to do with the obvious humor you point ...

2026-01-15T20:25:16Z

In reply to nevent1q…gl8q
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(This reply has nothing to do with the obvious humor you point out. I am, also humorously, taking you seriously when you probably didn't expect it. :-)

To be (more than) fair, MIT does have a remarkable humanities department. (Yes, "department": all humanities wedged into a single department. It's a niche interest at the Institute, though an intense niche.)

As a result, it takes a really *determined* professor to decide to teach there. They *really* want to spark an interest in the heads of the undergrads.

Heather Cox Richardson taught history.

Joe Haldeman taught writing.

Dirk Struik taught history AND mathematics.

I wasn't an undergrad in my time there, so I didn't have personal experience with "Course 21", as it was known. But EVERY SINGLE TIME I heard conversation about the quality of that small faculty, they were described as *excellent*.

But yeah, it's silly to put MIT at the top of the list for arts & humanities. You can GET a pretty good sideline in humanities there, but you have to seek it out.

> "No fields in the Lagrangian that can't be ...

2026-01-07T19:53:18Z

In reply to nevent1q…3a7y
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> "No fields in the Lagrangian that can't be varied!"

This does seem to be the general sentiment as far as fundamental physics goes.

But... when you let us humans introduce heuristics to do approximate calculations, all kinds of things turn out to be useful.

Effective field theory and mean field theory are good examples.

Energy levels in a nucleus are sort of hard ab initio, because the strong force resists perturbation theory. But mean field theories and things like the nuclear shell model (Mayer & Jensen, Nobel in 1963) engineers in a starting point. You start with the nuclear 2-body Hamiltonian, then add and subtract a 1-body potential 𝑈:

𝐻=𝑇+𝑉₂=[𝑇+𝑈]+[𝑉₂−𝑈]

Then you start exploring clever choices of 𝑈 that are calculationally tractable (at least numerically), will capture a few gross features (size of a nucleus) and zero out as many low-lying matrix elements of 𝑉₂−𝑈 as possible (to simplify perturbation theory).

The magic is that a simple harmonic oscillator potential for 𝑈 will do, and you can do perturbation on top of that. There are better ways, but the big surprise is that strongly interacting nucleons can be characterizsed at 0 order as otherwise free particles in a magic harmonic oscillator. Hence the stable nuclei with filled energy levels are called "magic number nuclei".

Anyway, the point here is that you can introduce this big static background potential and then perturb around it to get quite good results.

To your point: this is a calculational tactic, not fundamental physics.

https://en.wikipedia.org/wiki/Nuclear_shell_model

An acute observation.

2025-12-31T14:38:37Z

In reply to nevent1q…07p8
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An acute observation.

One of the things that was hardest for me to get my head wrapped ...

2025-12-24T17:07:31Z

In reply to nevent1q…dn99
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One of the things that was hardest for me to get my head wrapped around was that we perceive log frequency. Hence the octave is a doubling of frequency, and everything else, where people talk about "adding a semi-tone" is actually *multiplying* by something. (In modern scales, multiplying by a power of 2^(1/12).)

Music theorists are not a mathematical tribe, and for many years I just *could* *not* understand the word salad they wrote about this!

But then some book or other whose title involved "music" and "physicists" explained it all with just a couple equations.

But not Tmas? The world is, after all, Minkowskian. That 4th ...

2025-12-24T12:46:11Z

In reply to nevent1q…q52j
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But not Tmas?

The world is, after all, Minkowskian. That 4th time-like tree is essential, because otherwise how will you know when it's the holidays?

I once tried exhaustive proof search, but I just got exhausted.

2025-12-23T17:49:43Z

In reply to nevent1q…xk7t
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I once tried exhaustive proof search, but I just got exhausted.

Don't forget ℕ!

2025-12-11T19:13:37Z

In reply to nevent1q…s8v5
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Don't forget ℕ!

Hunh. There's a science fiction writer named Michael ...

2025-12-07T15:39:27Z

In reply to nevent1q…jpvm
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Hunh.

There's a science fiction writer named Michael Capobianco. Probably no chance they're the same, though.

https://en.wikipedia.org/wiki/Michael_Capobianco

No Hamiltonian?! OK, ya got me on that one. Ya got me really ...

2025-11-01T16:44:52Z

In reply to nevent1q…ayqx
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No Hamiltonian?!

OK, ya got me on that one. Ya got me really hard. This is a very, very different view of QM.

Do you have a slide set you can share?

2025-10-18T13:56:35Z

In reply to nevent1q…6yaj
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Do you have a slide set you can share?

Dang, I'm an hour late! :-)

2025-10-11T21:54:23Z

In reply to nevent1q…p0d2
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Dang, I'm an hour late! :-)

That's okay, I'm sure you can simulate the Jacquard cards ...

2025-10-09T16:02:53Z

In reply to nevent1q…rx7s
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That's okay, I'm sure you can simulate the Jacquard cards in software. :-)

Ah, but does it use punched cards, like a Jacquard loom? :-)

2025-10-09T14:57:01Z

In reply to nevent1q…5unl
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Ah, but does it use punched cards, like a Jacquard loom? :-)

Later that same year, somebody introduced me to John Ostrom's ...

2025-09-04T13:49:10Z

In reply to nevent1q…t7he
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Later that same year, somebody introduced me to John Ostrom's and Alick Walker's papers, saying basically that modern birds descend directly from dinosaurs. (Among other things.)

From this kind of shocking revelation I learned another hugely influential lesson in becoming a young scientist: *everything* I think I know is provisional, subject to revision by experiment, observation, and deeper reasoning.

Some things are more firmly established than others, of course, and are unlikely to be dislodged. (Sagan: "Extraordinary claims require extraordinary evidence.")

At first, I thought, "Well, there's always math. Surely *that's* safe, secure, and well founded." (No doubt you can imagine what happened next, but I was young and naïve and had no idea.)

Somebody told me about Gödel.

So I retreated and thought, "Ok, not all math, but at least logic is well founded, right?"

Somebody told me about Russell's Paradox. And then about Russel & Whitehead, just to rub it in.

So I retreated further and thought, "Ok, but at least *arithmetic* should be ok." At least Kronecker's "G-d given integers" should be safe, right?

Then somebody told me about Frege.

And it began to sink in that in our fallible, mortal, human state *everything* must be tentative at least to some degree. While there are reassuring degrees of certainty, there is no absolute certainty.

I learned a lot that year, most of it not especially related to class material but very much related to hanging out with professors.

https://en.wikipedia.org/wiki/Origin_of_birds#Ostrom,_Deinonychus,_and_the_dinosaur_renaissance

Not exactly about the exitinctions, but more of a personal ...

2025-09-04T13:40:47Z

In reply to nevent1q…9j0s
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Not *exactly* about the exitinctions, but more of a personal experience.

About dinosaurs, which for a physics student was a bit outside my usual range.

In about 1975 (or maybe 1976?), I was taking an undergrad class in electromagnetism. The prof came in, looked us over, and got that sly grin on his face that told you you were about to hear a really good story.

One that, as it turned out that day, was utterly unrelated to electromagnetism.

He proceeded to tell us about Luis Alvarez & son, looking at the geology of the K-Pg boundary (then called the K-T boundary?), finding that it contained *ridiculous* amounts of iridium. This led to the speculation that there was something like an asteroid impact to produce that layer of iridium (and, for that matter, ash), and it just happened to be at a dinosaur extinction event.

This wasn't to see publication for several more years, and was still on the physicist gossip circuit. It was thrilling to hear, of course, but it was the first time that I felt like an *insider* -- someone who was included in the gossip circuit. It was... like waking up and discovering that finally I had become a *scientist*, worth talking to by other scientists.

It never left me that one of the most important parts of teaching is to *let students in* to the community, and make them understand they're part of the community worth talking to by professionals.

https://en.wikipedia.org/wiki/Alvarez_hypothesis

For that, you want Cohl Furey and her octonionic versions of QM ...

2025-08-04T13:23:59Z

In reply to nevent1q…dcac
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For that, you want Cohl Furey and her octonionic versions of QM and the standard model:

https://en.wikipedia.org/wiki/Cohl_Furey

Best Scottish sign I've seen so far described him as an ...

2025-07-27T17:22:45Z

In reply to nevent1q…cp02
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Best Scottish sign I've seen so far described him as an "orange jobbie".

https://en.wiktionary.org/wiki/jobbie

I guess they missed gates F4 and G2? I'm tempted to say ...

2025-07-05T15:30:53Z

In reply to nevent1q…vs2h
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I guess they missed gates F4 and G2?

I'm tempted to say "All Lies!" except the pronunciation would be wrong.

But it certainly is... exceptional.

Welcome to the world of big institutions defending themselves. I ...

2025-06-27T17:05:12Z

In reply to nevent1q…tz46
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Welcome to the world of big institutions defending themselves.

I worked some years for a big pharma company. Every year, all 100,000 employees had to take ethics training, as in "why you should not bribe people in general, and 27 specific examples to sharpen the point".

This was usually part of a consent decree because some idiot behaved badly. So for 5 years or so we all had to take these courses, no matter how far removed we were (e.g., research for me).

My darker side theorizes that although part of it is to encourage ethical behavior, some of it was the company covering its behind. "Oh, trained them not to do that, so it's not our fault."

Still... it made me *really* angry at the ethics-free idiots who kept making it necessary.

Gee, I dunno. I have the same fantasy, but... Between being a ...

2025-05-22T16:16:25Z

In reply to nevent1q…yp2r
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Gee, I dunno. I have the same fantasy, but...

Between being a flare star (radiation nightmare), flares likely blasting away any atmosphere, tidal locking from having to be so close... that's a life-hostile environment.

Unless it's underground, or maybe under ice in a water world.

Both of those seem to argue against evolving life that will look up at the stars very much. For them, the sky would be *dangerous*.

That leaves troublemaker refugees like us, migrating to red dwarf systems to live underground. And interstellar travel is *hard*.

And don't even get me started about the financial and banking issues raised by Paul Krugman in his "Theory of Interstellar Trade" monograph. :-)

https://www.princeton.edu/~pkrugman/interstellar.pdf

Sidney Coleman, when teaching quantum field theory, used to talk ...

2025-05-19T14:23:27Z

In reply to nevent1q…d8z3
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Sidney Coleman, when teaching quantum field theory, used to talk about "the missing box."

He'd draw a 2x2 table whose rows were labelled "classical" and "quantum" and whose columns were labelled "single particle" and "continuum". (No idea if the ASCII art below will come out ok.)

| Single | Continuum
----------------------------------------
Classical | part. mech. | fluid mech
----------------------------------------
Quantum | quantum | ?

It's easy to see classical particle mechanics and classical fluid mechanics in the first row.

In the second row, single-particle quantum mechanics, from quantizing classical mechanics, is also pretty clear.

QFT is the empty box on the lower right. We get there by applying extreme many-particle methods to quantum mechanics, and patching up all the places where that breaks.

I asked him once why we don't consider the other path, that of quantizing fluid mechanics. He looked at me very strangely, and a few years later I understood why. :-)

It might be fun to think about this in the context of acoustic ...

2025-05-15T15:20:41Z

In reply to nevent1q…zzux
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It might be fun to think about this in the context of acoustic black holes (link below). I think superradiance -- extracting energy from a black hole -- has been experimentally seen with acoustic black holes.

I first heard Unruh talk about this in a seminar back in the 1980s or 1990s, I think.

Basically: A fluid flows radially inward toward a drain at the origin, with speed increasing as the radius diminishes. If the speed at some finite radius exceeds the fluid's sound speed, then acoustic energy can't escape outside that radius.

At that point, you've got a singularity and an event horizon, and hilarity ensues in various ways. Hawking radiation happens when phonon pairs are thermally created near the "horizon".

https://en.wikipedia.org/wiki/Sonic_black_hole

My neighbor's a retired EE prof, who was working on some ...

2025-05-13T20:07:40Z

In reply to nevent1q…vd0r
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My neighbor's a retired EE prof, who was working on some historical documents about Tesla.

Turns out Tesla never quite grasped the other half of Maxwell's equations, and thought "Hertzian Waves" (as he sarcastically dismissed them) were an hallucination. He apparently thought long-distance communication was via some kind of ground fault through the earth.

Your mention of the ionosphere, the F2 skip, and meteorites reminded me of the lengths to which Tesla went to rationalize the results.

The \( \mathbf{E} \) field puts energy into the fluid when it ...

2025-05-11T15:43:54Z

In reply to nevent1q…c24j
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The \( \mathbf{E} \) field puts energy into the fluid when it induces dipoles.

That energy partly goes into rotation and partly into heating the fluid as the dipoles are disrupted thermodynamically (collisions with fluid molecules, or lattice vibration of the solid body).

The dipoles point in a direction to reduce the applied field, which will have to be maintained externally.

I just noticed that TB Jones is the author of the article you ...

2025-05-11T15:32:52Z

In reply to nevent1q…79tj
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I just noticed that TB Jones is the author of the article you cite and the book that I cited.

So we're on the same trail!

I suspect there's an explanation in TB Jones, ...

2025-05-11T14:39:08Z

In reply to nevent1q…uzhd
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I *suspect* there's an explanation in TB Jones, _Electromechanics of Particles_, Chapter 4 (summary below).

However, I don't have access and the Wayback Machine copy is restricted. Perhaps someone else has access?

https://archive.org/details/electromechanics0000jone/page/270/mode/2up

Well, at least it's correct. Trivial, sure. But not an ...

2025-05-11T12:54:57Z

In reply to nevent1q…3j8n
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Well, at least it's *correct*. Trivial, sure. But not an hallucination.

(Maybe it's just the zeitgeist. I've been lowering my expectations a lot.)

I remember a physics colloquium in the 80s when we saw some of ...

2025-05-09T14:15:46Z

In reply to nevent1q…gkkx
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I remember a physics colloquium in the 80s when we saw some of the first images of the sheer *complexity* of the rings, and how much is going on in the "gaps".

That was the first time I heard the phrase "shepherd moon". Nobody, as I recall, predicted them. But the moment you saw them, it was clear they were inducing waves and even braids.

Absolutely gorgeous.

(Though a quick search didn't find any images of braided rings, so maybe that memory is unreliable.)

Yup. They didn't hand a Nobel to Maria Goeppert Mayer for no ...

2025-04-09T12:35:02Z

In reply to nevent1q…99hv
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Yup.

They didn't hand a Nobel to Maria Goeppert Mayer for no reason. (And someone else, whose name eludes me at the moment? And Wigner the same year, for other reasons.)

What really struck me in grad school was how the shell model ...

2025-04-08T17:04:52Z

In reply to nevent1q…twun
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What *really* struck me in grad school was how the shell model can work *at all* with such strongly interacting particles. I mean... the shell model puts them in a 3-dimensional harmonic oscillator and calls it a day; you do perturbation theory on top of that (e.g., Hartree-Fock correction terms).

The key insight is that the strong force is so short-range. Replacing it by a global potential is not something I'd have thought about in a million yeaars.

I was a nuclear physicist -- of sorts -- like 30 years ago ...

2025-04-06T21:27:59Z

In reply to nevent1q…tgus
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I *was* a nuclear physicist -- of sorts -- like 30 years ago doing my thesis. (Actually, it ended up more like many-body theory and adiabatic approximations in in QM.)

But once upon a time I tried something like this in neutron stars. Think of nuclear matter as an infinite nucleus, so states must be translationally invariant and are plane waves. The dispersion relation \(\omega(k)\) to be determined from the particular nuclear potential chosen.

If you can somehow select the right spin states, I thought maybe I could get a superfluid condensate.

Nothing came of it, though.

The IBM folk got some good approximate nuclear models, though like you I never really investigated why.

A critical system should, in general, not have single points of ...

2025-03-14T13:40:45Z

In reply to nevent1q…y5dm
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A critical system should, in general, not have single points of failure.

Sadly, the US has shown it is *determined* to impose failures.

TIme to bring back the arXiv mirrors, no?

2025-03-14T01:40:40Z

In reply to nevent1q…k8d4
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TIme to bring back the arXiv mirrors, no?

So... apparently not an adequate proof by induction that it's ...

2025-03-12T13:17:27Z

In reply to nevent1q…3ejx
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So... apparently not an adequate proof by induction that it's always funny, then.

C'mon, it's a little bit funny, unless you're just ...

2025-03-12T02:24:35Z

In reply to nevent1q…zyvx
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C'mon, it's a *little* bit funny, unless you're just being saturnine!

https://dictionary.cambridge.org/us/dictionary/english/saturnine

A long tradition of Japanese weaponized tubas. (Pic below is ...

2025-03-07T16:28:07Z

In reply to nevent1q…4mz4
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A long tradition of Japanese weaponized tubas.

(Pic below is actually of pre-radar acoustic listening devices to detect incoming aircraft.)

Heh. "Curb the... incompetence... of HR", he says. Oy... ...

2025-02-15T14:56:54Z

In reply to nevent1q…dzep
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Heh. "Curb the... incompetence... of HR", he says.

Oy... have I got a story for you!

I am a scientist, now retired. I worked in cancer research at a big pharma, mostly doing applied math & statistics, with the occasional bit of machine learning. (Physicist by training, it says here on my PhD.)

About 2010, we wanted to hire some next-gen sequencing people to run a new part of our lab. We duly wrote the req, and submitted it to HR for a candidate search.

HR *rewrote* the req, introducing numerous technical errors which would be off-putting to any qualified applicant.

More interestingly, they added the requirement for TEN YEARS OF EXPERIENCE... for a technology which had been commercially available for less than 5 years or so. As evidence of that, see the plot below, and note the sharp drop in sequencing costs starting 2007-2008.

So unless you were intending to hire the NGS inventors themselves, there could not possibly be *any* candidates!

When confronted with this impossibility, they held their ground saying 10 years was the minimum experience they required for this senior position, and they could not make any exceptions. We would just have to wait for candidates to "age into the seniority required for the position."

Of course we ended up doing an end run around HR, hired a couple fabulous candidates, and (again, *of course*) got into trouble for it.

HR continued to say "scientists are remarkably uncooperative".

That part, at least, was accurate.

"Cooperation" would have been foolish.

I Mobley, "A brief history of Next Generation Sequencing (NGS)",
Front Line Genomics, 2021-Jul-26. Figure 1 is reproduced here.

https://frontlinegenomics.com/a-brief-history-of-next-generation-sequencing-ngs/

Oddly enough, the next one in the sequence is "estoppel". ...

2025-02-09T01:17:13Z

In reply to nevent1q…d9he
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Oddly enough, the next one in the sequence is "estoppel". :-)

Slightly less recognizable in modern English, but along the same lines.

https://en.wikipedia.org/wiki/Estoppel

Like "cease" and "desist".

2025-02-09T00:26:41Z

In reply to nevent1q…06w9
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Like "cease" and "desist".

Lot of us feel like that right now.

2025-01-24T02:44:35Z

In reply to nevent1q…dt3j
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Lot of us feel like that right now.

Strongly evokes a half-remembered illustration in one of Larry ...

2025-01-13T00:37:25Z

In reply to nevent1q…teu8
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Strongly evokes a half-remembered illustration in one of Larry Niven's "Known Space" novels.

Your plot always reminds me of something most people find ...

2025-01-08T17:58:25Z

In reply to nevent1q…ch5v
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Your plot always reminds me of something most people find counterintuitive: a practical fusion reactor must be much *hotter* than the sun.

That's because the sun's fusion reaction rate is very, very slow -- less thermal output than a resting human body!

We can even compute the power output (solar luminosity, human head production) and get the power output per unit mass.

The sun is such a big deal power-wise mostly because there's so *much* of it!

Source: https://nssdc.gsfc.nasa.gov/planetary/factsheet/sunfact.html

Lsun = 3.82e26 watt
Msun = 1.99e30 kg
Lsun/Msun = 3.82/1.99 x 10^-4 watt/kg = 1.92 x 10^-4 watt/kg

Source: https://www.researchgate.net/figure/Heat-Production-Rate-in-a-Human-Body_tbl2_271444362

Lhuman = 100 watt (60-250 watts, depending on activity; 100 watts is for sitting)
Mhuman = 50 - 100 kg, call it the middle at 0.75e2 kg
Lhuman/Mhuman = 100 / 50-100 = 1-2 watts/kg

So a human body, at rest, produces around 10^4 times as much power per unit mass as the sun.

Because that force on the plasma will shove the plasma (density ...

2024-12-26T22:19:28Z

In reply to nevent1q…sz7d
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Because that force on the plasma will shove the plasma (density & current) around in such a way that it will produce straighter field lines.

I believe it's hard at first to think this way because:

(a) We teach Maxwell's equations for the fields as though the charge density and current are fixed, externally given.

(b) We teach mechanics as though the forces are fixed, externally given.

But in plasma, both the fields and the motions of the charges are variable and interacting. So there's lots of nonlinearity: the field appears to interact with itself, because it does so indirectly via the plasma.

There's a similar thing in QFT where the matter fields and the gauge fields do this (though with added self-nonlinearity).

You might be amused by the story of restoring Voyager I to ...

2024-12-26T13:44:21Z

In reply to nevent1q…qa66
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You might be amused by the story of restoring Voyager I to communicating status (which I described as "remote debugging, extreme sports division"):

https://blogs.nasa.gov/voyager/2024/04/22/nasas-voyager-1-resumes-sending-engineering-updates-to-earth/

Voyager 1 & 2 have (2012 and 2018, respectively). One can ...

2024-12-25T18:20:43Z

In reply to nevent1q…qmt2
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Voyager 1 & 2 have (2012 and 2018, respectively). One can argue that Pioneer 10 & 11 have as well, but contact with them has been lost.

I recall some striking plots showing a dramatic decrease in the flux of particles in one instrument or another at the boundary.

Here's a table of all the probes in the get-outta-the-solar-system sweepstakes:

https://en.wikipedia.org/wiki/List_of_artificial_objects_leaving_the_Solar_System

And here's the NASA announcement about Voyager 2 passing outside the solar system:

https://www.nasa.gov/news-release/nasas-voyager-2-probe-enters-interstellar-space/

Happy Christmas to you, too! And upcoming Hogmanay, since I seem to recall you're in Scotland now.

The other place where solar wind is pretty interesting is the ...

2024-12-25T14:11:18Z

In reply to nevent1q…nzaw
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The other place where solar wind is pretty interesting is the heliopause: where the ram pressure from the solar wind equals the nearly-ideal gas pressure of the interstellar medium.

As good as anything for the outer boundary of the solar system (or at least the termination shock part of it, which is more nearly spherical).

Sort of the opposite end of the neighborhood where the PSP is going.

The a capella choral performances are also not to be missed.

2024-12-13T21:15:49Z

In reply to nevent1q…tj3j
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The a capella choral performances are also not to be missed.

Ah, John Cage! I've always wanted to start a conspiracy ...

2024-12-13T20:59:47Z

In reply to nevent1q…wwn3
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Ah, John Cage!

I've always wanted to start a conspiracy theory that if you listen to his 4' 22" *backwards*, then you hear dark, secret messages.

Today's blog post, brought to my attention by: ...

2024-12-11T20:32:01Z

Today's blog post, brought to my attention by:
[@sphakos](https://toot.cat/@sphakos ) [@jenniferplusplus](https://hachyderm.io/@jenniferplusplus )

In the 2022 tech layoffs, 70% of those laid off were women, who made up only 20% of the tech workforce.

Does a Bayesian analysis show this is evidence of bias? Yes, by a factor of 8.8x in the male/female likelihood ratio.

https://www.someweekendreading.blog/2022-tech-layoffs-bias/

This is how I feel about point-free notation. Theoretically ...

2024-11-21T15:16:53Z

In reply to nevent1q…x6c3
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This is how I feel about point-free notation.

Theoretically elegant, but it turns everything into a puzzle.

Solving Wordle in Old High Martian is a hobby for which nobody need fear judgement, but it feels awkward to be drawn into it unsuspectingly!

DIdn't Ken Forbus invent a lot of this back in the 80s, with ...

2024-11-14T21:48:21Z

In reply to nevent1q…4hyv
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DIdn't Ken Forbus invent a lot of this back in the 80s, with "qualitative process theory"?

For example, your qualitative addition table is pretty close to Figure 5, page 97 (page 14 of the PDF), below.

https://apps.dtic.mil/sti/tr/pdf/ADA465743.pdf

Looks related to Goldberg polyhedra? ...

2024-10-25T17:48:42Z

In reply to nevent1q…79mh
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Looks related to Goldberg polyhedra?

https://en.wikipedia.org/wiki/Goldberg_polyhedron

I'm not particularly opinionated on the various curry paste ...

2024-10-12T20:27:39Z

In reply to nevent1q…rx53
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I'm not particularly opinionated on the various curry paste flavors.

The Japanese ones are all pretty good. As you move more toward southeast Asia, they emphasize coconut more, which is not to my taste.

To me what matters is the quality of the broth you start with. If I start with a broth I made myself from roast chicken bones and veggies, it's very good with lots of gelatin for mouth feel. If I start with a boxed chicken broth, it's still ok.

Then I'm compulsive about adding lots of fresh veggies, usually a mirepoix of carrots, lots of onions, and celery to which I add lots of mushroom (button or crimini). Sometimes coarse-chopped caultiflower. (If we were in Japan, there would be other vegetables.)

My spouse prefers adding chicken thighs, while I prefer a firm tofu. Both are good.

Finally, I add enough curry paste to get the taste right, but the texture isn't thick enough. More curry paste would correct that, but the curry flavor would overwhelm everything else. So I resort to either gently stirring in small amounts of unflavored gelatin, or a corn starch slurry to adjust the texture.

It usually freezes pretty well.

It's a Japanese product (though labelled in English, as ...

2024-10-12T18:41:22Z

In reply to nevent1q…70qa
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It's a Japanese product (though labelled in English, as it's the export version).

So when I make curry for my Japanese spouse, she endorses it as The Real Thing.

Just made a curry with this for dinner! (Ok, the milder version.) ...

2024-10-11T22:20:43Z

In reply to nevent1q…32dt
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Just made a curry with this for dinner! (Ok, the milder version.)

They call it "Vermont" apparently because of the apple.

Pretty good stuff.

No idea what system you're thinking about, but you might be ...

2024-09-13T14:20:27Z

In reply to nevent1q…vgsa
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No idea what system you're thinking about, but you might be somewhat interested in dbos. It replaces most of an OS with a DBMS (just a tiny, stripped-down core of Linux to launch it all).

Directories are tables. Files are tables. Processes interlock thorugh tables.

The shell is SQL-like.

https://www.dbos.dev/

There have been some unfortunate accidents with Teslas in which ...

2024-09-08T20:41:58Z

In reply to nevent1q…stsx
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There have been some unfortunate accidents with Teslas in which people died because they emergency door pull is *behind* an upholstery panel and not labelled.

Angela Chao (sister of Elaine Chao, former Trump Secy of Transportation and spouse of Senate Majority Leader McConnel) drowned in such an accident in her Tesla.

Some details on the (lack of) safety engineering here:

https://www.someweekendreading.blog/tesla-unsafety/