A main-sequence star's orbit brought a black hole's spin within reach. Physicists reproduced the excitation spectra of conformal field theories, and an electron beam turned a silicon crystal into a microscopic interferometer.
A faint main-sequence star orbiting Sagittarius A* peaks at a speed of 25,000 km per second, bringing the black hole's spin into view. The 4.3 million solar mass object sits at the center of the Milky Way, and earlier stellar orbits had exposed strong relativistic effects without reaching the spin term. The newly mapped star, S301, has a K-band magnitude of 19.3 and passes close enough to allow near-infrared interferometers to register its response to the rotation.[1]
Physicists tuned a chain of Rydberg atoms to quantum phase transitions to resolve excitation spectra that match the universal values predicted by conformal field theories. The team used local control to separate excitations by their parity under reflection. The modulation technique allowed them to drive transitions between distinct spectra that belong to different boundary conditions within the tricritical Ising chain.[2]
Focusing an electron beam across two silicon atomic columns turned a crystal into a microscopic interferometer. The neighboring silicon columns were set 1.36 ångström apart, and the two atomic slits vibrated strongly at finite temperatures. Those vibrations imprinted their motion on the resulting fringes, and the remaining visibility provided a measure of how the neighbouring columns vibrate together.[3]
