MIT physicists improved the stability of optical atomic clocks by reducing “quantum noise” — a fundamental measurement limitation. The work could enable more precise, portable optical atomic clocks that track even tinier intervals of time, up to 100 trillion times per second.

Wetlands act as nature’s kidneys: They trap sediments, absorb excess nutrients and turn pollutants into less harmful substances. Now, the list of pollutants wetland plants can remove includes per- and polyfluoroalkyl substances (PFAS). From a greenhouse study, researchers in ACS’ Environmental Science & Technology report that moisture-loving yellow flag irises and fungi on their roots are a promising combination for PFAS removal. As part of a constructed wetland, this pair could effectively treat contaminated wastewater.

Hydrogen is a promising fuel for developing sustainable industrial processes, but its use is hindered by hydrogen embrittlement—a phenomenon that weakens metals and can cause sudden failure. Now, researchers from Japan have provided the first experimental evidence linking surface roughness to atomic-scale defects caused by hydrogen in iron. Using positron annihilation lifetime spectroscopy, they showed that rougher surfaces result in greater accumulation of defects, offering new insights into designing hydrogen-resistant materials through precision surface engineering.

Sodium-ion batteries (SIBs) are a promising, low-cost alternative to lithium-ion batteries for both personal electronics and large-scale energy storage, but their adoption is limited by their poor stability in air and water. In a recent study, researchers from Japan addressed this challenge by doping the SIB cathode material Na_2/3[Fe_1/2Mn_1/2]O₂ with calcium. This simple modification greatly improved stability and performance, paving the way for more practical and sustainable battery technologies.