Hanzhe Liu

A laser strikes the crystal, and it responds with flashes of light, like a bell ringing after a blow. But if the bell is warm, its sound wavers and fades. Same here: the crystal's atoms constantly jitter from heat, and this jitter disrupts the electrons' smooth flight, making the light dim and blurry.

A laser pulse slams into a crystal of Ca0.4Sr0.6CuO2, and inside the chains of copper and oxygen atoms a dance begins that lasts less than one millionth of a nanosecond. In an ordinary conductor, electrons run freely through the material, but here strong Coulomb repulsion pins them in place like passengers in a packed bus.