Analysis: Science & Technology — 08 October 2026
Pair-density waves persist in uranium ditelluride after superconductivity vanishes
Physicists at the University of Illinois Urbana-Champaign report that electron pairs in uranium ditelluride form rippling pair-density waves that remain after the bulk superconducting state has gone. The measurements, published in the Proceedings of the National Academy of Sciences and highlighted on 7 October, are the first in this material to match the temperature and magnetic-field behavior predicted for that state above the critical temperature. The result matters because standard theory ties Cooper-pair formation to the superconducting transition itself.
Uranium ditelluride superconducts only below about 2 kelvin and is widely treated as a spin-triplet superconductor, closer in pairing symmetry to superfluid helium-3 than to ordinary BCS metals. Eduardo Fradkin and colleagues predicted pair-density waves in 2007, including the possibility that they could exist above the critical temperature. Vidya Madhavan’s group used scanning tunneling microscopy on cleaner crystals, with a vector magnet able to apply fields along different crystal axes.
The evidence is indirect. The microscope records a surface charge modulation, not zero resistance through the crystal. Some charge-density-wave peaks vanish near the bulk critical temperature, while others survive and are suppressed by field in a pattern that tracks the anisotropic upper critical field. Whether the same order exists in the bulk is still open.
Sources: ScienceDaily; Proceedings of the National Academy of Sciences; University of Illinois Grainger College of Engineering.
Webb spectra tie warm dust around young stars to Mars-sized collisions
James Webb, with archival Spitzer spectra, has given astronomers the first sample large enough to sort extreme debris disks by mineral composition. Kate Su and colleagues analyzed 21 systems in The Astrophysical Journal; the findings were reported widely on 7 October. About one-third are silica-rich, which the team links to impacts energetic enough to vaporize rock between bodies roughly the size of Mars.
These disks are rare, seen around roughly 1 percent of young stars, and lie in the warm zone where rocky planets form. Their grains are smaller than those in ordinary debris disks, their warm-dust content is high, and their infrared brightness varies irregularly. The silica-poor majority is read as lower-energy events, including grazing collisions between Moon-sized bodies, and appears around stars of a wider range of ages.
The collision sizes are inferred, not imaged. Planetary embryos of this scale are too small to resolve, so the mineral fingerprints carry the argument. Silica-rich disks have so far been found only around stars younger than 300 million years, a window consistent with terrestrial-planet assembly and the estimated timing of the Moon-forming impact. That age split rests on only three older disks, so it still needs a larger census.
Sources: ScienceDaily; NASA; The Astrophysical Journal.
Webb finds evidence of an atmosphere on the lava world HD 3167 b
A University of Chicago-led team reports strong evidence that the rocky super-Earth HD 3167 b keeps an atmosphere despite orbiting its star once a day. The planet, 154 light-years away, is a lava world whose star-facing surface is expected to be molten silicate. It is the coldest such world yet with atmospheric evidence, which matters because astronomers are searching for the temperature where these atmospheres appear or vanish.
The measurement used a secondary eclipse in the mid-infrared. The light lost when the planet passed behind the star gave the dayside temperature. A bare rock should sit near the theoretical maximum set by distance and reflectivity. HD 3167 b is cooler than that limit, the signature expected if gas moves heat to the night side or clouds reflect starlight.
The detection does not identify the gas. Vaporized rock was the default expectation, but other lava worlds have hinted at heavier species such as carbon dioxide, carbon monoxide, or water. A cooler dayside can also come from clouds or an uncertain albedo. The planet is far too hot for liquid water; the useful comparison is the early magma-ocean Earth, not habitability.
Sources: ScienceDaily; University of Chicago; The Astrophysical Journal Letters.