Researchers created an atomic-scale version of Newton’s cradle to study thermal equilibrium
SANTA BARBARA, Calif. — A simple toy is helping scientists understand new details of a mysterious quantum process.
The rhythmic click-clacking of the metal balls in Newton’s cradle has long entertained physics students. Now, scientists have re-created the toy on an atomic scale, using it to probe how quantum systems reach a balanced state known as thermal equilibrium.
Leave a mug of hot coffee on the counter, and it will gradually cool until it reaches thermal equilibrium, matching the temperature of the room. That process, called thermalization, is well understood on the scale of coffee cups. But at the quantum level, thermalization becomes murky.
“This is an area of physics that we fundamentally don’t understand,” says physicist Benjamin Lev of Stanford University, who presented the work June 26 at the Quantum Thermodynamics meeting at the Kavli Institute