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[2026-08-19] · src Chhetri, Studer, Raeder, et al. (JGU Mainz / HIM / GSI-FAIR / Gothenburg, 18 institutions); Phys. Rev. Lett. 136, 192501 (2026)
Nuclear shape in the heaviest actinides has mostly been inferred indirectly, because the isotopes decay too fast and are made in numbers too small for most spectroscopic techniques. This collaboration ran in-source hot-cavity laser spectroscopy on reactor-produced 255Fm at the RISIKO mass separator, using the PI-LIST ion source to resolve the hyperfine structure of two atomic transitions at 398.4 nm and 398.2 nm. Combined with atomic-structure calculations, the hyperfine pattern gives a magnetic dipole moment mu = -0.75(5) mu_N - consistent with the neutron occupying the 7/2[613] Nilsson orbital - and an electric quadrupole moment Q_s = +5.84(13) eb, confirming a strongly prolate deformation and correcting unphysical values that had stood in standard nuclear-data tables.
Nuclear shape controls how resistant a superheavy nucleus is to spontaneous fission, which is the practical limit on how far the periodic table can be pushed. This is a real measurement standing in for what had been a model-dependent estimate, and it reproduces what state-of-the-art mean-field and shell-model calculations predicted - a validation of the models the search for longer-lived superheavy elements has to rely on, rather than a surprise.
[2026-08-19] · src Chang et al.; Phys. Rev. Lett. 137, 076301 (2026), Editors' Suggestion
Twisted bilayer graphene is well studied near the magic angle (~1.1 degrees) and treated as electronically uninteresting at large twist angles, where the layers are assumed to decouple. This group looked instead at the crossover near 29 degrees, next to the exactly-quasicrystalline 30-degree point. Atomic-resolution TEM shows the two layers sitting in an intermediate, nonperiodic structural regime - near-dodecagonal quasicrystalline symmetry coexisting with emerging moire periodicity, rather than a clean handoff from one order to the other. Magnetotransport in the same samples finds strong interlayer hybridization mediated by Umklapp scattering, showing up as magneto-intersubband oscillations and a Landau-level spectrum that jumps from fourfold to twelvefold degeneracy across the crossover.
"Large twist angle means decoupled layers" has been a standing simplifying assumption used to treat those angles as a control case. This shows real electronic structure there instead, tied to a nonperiodic atomic geometry that ordinary Bloch-theorem band structure cannot describe cleanly. It reopens large-angle twisted graphene as a place to look for coupling effects rather than a null case, though whether the effect is particular to graphene-on-graphene or generalizes to other twisted moire stacks is still open.
[2026-08-19] · src (IXPE/NICER/Parkes collaboration); Nature (2026), arXiv:2509.19446
QED predicts that a strong enough magnetic field polarizes the vacuum itself into a birefringent medium, rotating and filtering the polarization of light that passes through it - a 90-year-old prediction never directly tested. Coordinating X-ray polarimetry from IXPE and NICER with radio timing from Parkes on the radio-loud magnetar 1E 1547.0-5408, this team finds phase- and energy-resolved X-ray polarization reaching 65% at 2 keV and dropping sharply between 2-4 keV - a pattern the paper argues standard, non-refractive surface-emission models cannot reproduce, but that vacuum-birefringence-governed propagation through the magnetosphere can. Flagging this explicitly as contested: an independent April 2026 analysis of the same IXPE dataset, using a different geometric model of the emission region, concludes the data do not compel a birefringence interpretation.
If it holds up, this is the first real observational handle on strong-field QED rather than a lab test at accessible field strengths - but "if it holds up" is doing real work here. The two groups disagree about the same public dataset over how the emission geometry is modeled, not about what was measured, so the open question is whether an independent polarization dataset, or a model-independent test, can break the tie.
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[2026-08-19] · src build/orrery-test.el
orrery-test--public-symbols (orrery-test.el:918-930) opens with a call
that touches nothing this codebase built: (mapatoms (lambda (sym) ...)).
mapatoms walks the obarray — Emacs's own global symbol table, every
name interned anywhere in this process, from orrery-build-ir to car to
a variable some other loaded package defined — and calls the given
function once per symbol object, not per string. sym inside that
lambda is not the text "orrery-build-ir", it is the interned symbol
itself, which is why the very next line has to call (symbol-name sym)
to get a string worth pattern-matching with string-prefix-p and
string-match-p. Two predicates then decide whether that symbol is worth
keeping: (fboundp sym) is true when the symbol has a function
definition attached (an orrery-build-ir-shaped symbol), (boundp sym)
is true when it has a variable value attached (an
orrery-test-golden-stamp-shaped one) — a symbol can be neither, either,
or both, which is why the filter is (or (fboundp sym) (boundp sym))
rather than just one of the two. orrery-verify-docs (orrery-test.el:
932-945) then walks that filtered, sorted list and calls (documentation
sym) for anything fboundp and checks the variable-documentation
property for anything boundp, failing the gate if either comes back
nil.
This is the first gate in the file that is not shaped like the other
six. orrery-verify-schema, -golden, -tags, -markup and -blocks
all check data this build produced — a JSON file on disk, a table of
Org fixtures, a rendered string — against an expectation written down
somewhere else. orrery-verify-docs checks *the running Lisp image
itself*: it asks Emacs, at runtime, "what symbols do you currently have
loaded, and which of the ones this codebase owns lack a docstring?" No
fixture, no golden file, no comparison against anything on disk — the
program is inspecting its own symbol table. That is also why
orrery-test.el bothers to (require 'orrery-cli) even though nothing
in the file calls a CLI function (line 39's comment says so directly):
mapatoms only sees a symbol if it has been interned by something
load-ing that file first, so a public function in a file nothing
requires is invisible to this gate, silently, which is a sharper
failure mode than a docstring gate usually has.
Exercise (verifiable, no repo file touched): run this from the repo root and read what comes back before running the next line:
emacs -Q --batch -L build -l orrery-test.el \
--eval '(message "%d public symbols, %d functions among them"
(length (orrery-test--public-symbols))
(length (seq-filter (function fboundp) (orrery-test--public-symbols))))'Then extend the check the brief's :CONCEPT: line points at — "no public
function exceeds 30 lines" — without editing build/: write a scratch
--eval that, for each symbol orrery-test--public-symbols returns
where (fboundp sym) holds, calls (find-function-noselect sym) to get
the buffer and position of its definition (not its byte-compiled
form — run this against a git clone, not an installed package, or
find-function-noselect has no source to point at), then
forward-sexp from that position to the closing paren and diffs
line-number-at-pos before and after. Report any symbol over 30. In one
sentence: why does this exercise have to call find-function-noselect
at all, instead of just taking (length (split-string (format "%S"
(symbol-function sym)) "\n")) — what does the printed representation
of a compiled function's value not contain that the source file does?
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[2026-08-19] · src —
hearClifford Brown & Max Roach — Joy Spring (Clifford Brown and Max Roach) · Tidal · Spotify
The head is built almost entirely from wide, unhesitant interval leaps that never sound reached-for — the exact quality today's technical target is after. Worth a listen once before picking up the horn, to hear what "centered" sounds like at speed, and once after, to hear how close the practice room got.
[2026-08-19] · src —
Today is interval work on trumpet: the last two sessions covered tone and time feel, so intervals are the piece that has gone longest unaddressed — the half of Scales & intervals the brief itself calls neglected. Wide leaps also sit well this soon after a layoff, unlike register or tonguing-speed work, so today stays clear of both.
Lip slurs through the octave, low C up to C' and back down, at mp, one long breath per slur, no articulation — just the air changing the partial. Five minutes, stop as soon as the slurs stop connecting smoothly.
Arban, Scales & intervals: the octave and major-sixth leap studies. Target quarter = 100, slurred, three consecutive clean passes — clean meaning the top note is centered and speaks immediately rather than being approached from below. Drop the tempo eight clicks the moment a top note goes sharp-and-thin under pressure instead of pushing through at speed.
Art of Phrasing, Melody No. 12. Let the phrase's own leaps carry the way the technical work just built — no extra push on the interval, just the line moving through it. Sing the phrase once before playing it.
Stop the moment a leap's landing note spreads or goes flat instead of speaking centered — that's the chops telling you the interval work has started costing accuracy elsewhere. Ten minutes short and clean beats one more leap that misses.