Most of us recognize basic phases of matter and their properties: solids maintain their shape, liquids flow freely with constant volume, and gases expand to fill their container. Quantum phases, on the other hand, are much harder to categorize, overturning traditional notions of what a phase even is and forcing physicists to rethink their definitions.

Every black hole hides a question at its center. Einstein’s theory predicts that whatever falls in is crushed into a singularity, a point of infinite density where the theory itself breaks down. Most physicists expect quantum gravity to replace that point with something finite. But the center lies hidden behind the horizon. How could we ever learn what is there?

For highly fragile quantum information systems, the ability to store quantum information is vital—but also challenging. Quantum information is transported in particles of light called photons, which often must be temporarily paused (or “stored”) while other, slower quantum operations catch up. This storage must be performed on microchips as small as 1 centimeter (0.4 inches)—a distance covered by light in a few trillionths of a second. Storing photons for a microsecond would represent a massive leap forward for the capabilities of quantum chips.

University of Glasgow researchers are part of an international collaboration that could lead to a new generation of quantum sensors. The team, which included researchers from the University of Tokyo, University of Glasgow, University of Sheffield and Kobe University, has for the first time used light to read out the magnetic spin of electrons trapped inside a porous crystalline material known as a metal-organic framework (MOF).