Xiao Li

Spontaneous emission was long considered fickle: a quantum dot emits a photon, obeying only probability. The Purcell effect allowed amplifying it by placing the emitter in a resonator, but that only changed the rate, not the spectral shape.

The cell membrane isn't just a wall; it's a turnstile gate. Embedded within it are protein channels that let ions in and out, creating an electric charge, like a battery that powers nerves and muscles.

Galileo, legend has it, dropped balls from the Tower of Pisa to prove that heavy and light objects fall equally. This law formed the foundation of Einstein's theory of gravity. Today, scientists have turned an entire space station into such a tower.

A deck of cards in which each card is slightly rotated cannot lie flat: the backs and faces will never align. But if the cards are flexible, they will start to adjust, shifting by fractions of a millimeter to find the perfect match. Something similar happens inside crystals when two thick layers of MoS2 or MoS2 with WS2 are stacked with a twist of 1–2 degrees.