Dmitry Budker

Among the fundamental symmetries of nature, mirror parity holds a special place. The Standard Model already knows one violation of it, in the weak interaction, but hypothetical long-range forces that don't conserve left and right could reveal a lot about dark matter.

Heat an ordinary quartz watch by ten degrees, and it will start losing seconds each day. Atomic clocks are more precise, but they take up an entire cabinet. Diamond with a tiny defect, a nitrogen vacancy, promises atomic-clock accuracy in the volume of a grain of sand.

A tiny defect in diamond is like a microscopic ear, able to pick up the magnetic 'breath' of the heart. Such sensors work at room temperature and are no bigger than a grain of sand.

To align particle spins in one direction, physicists usually cool a substance to near absolute zero and place it in a strong magnetic field. That is expensive and bulky. A new method resembles tuning many spinning tops with a gentle touch: mediator molecules temporarily bind to target atoms and pass on their order.

In deep cold, at a temperature just two degrees above absolute zero, a copper cavity the size of a saucepan listens to the silence of the universe.

Tiny magnets inside atoms, nuclear spins, can 'freeze' for long minutes in a cold crystal. This hinders the quick tuning of quantum sensors: everything takes too long to reach the desired state. Physicists have found a way to nudge them with light.

In the pitch darkness of a vacuum chamber, a tiny magnet floats. It touches no walls and loses almost no energy — an ideal sentinel, ready to catch the faintest nudge. Such a sentinel is exactly what you need for axion hunting. These particles are prime suspects in the case of the Universe's hidden mass, which we call dark matter.