Scientists discover atoms suddenly spinning backward in quantum experiment

Scientists have directly watched angular momentum move through a crystal for the very first time — and discovered a bizarre twist along the way. Using ultra-powerful terahertz laser pulses, researchers triggered tiny atomic rotations inside a quantum material and found that the direction of rotation can unexpectedly flip as momentum is transferred. The strange reversal happens because of the crystal’s underlying symmetry, creating an almost impossible-sounding effect where two rotations combine into one spinning the opposite way.

Raccontata dasciencedaily.com