Theoretical physicist Jens Koch tilts the tiny object on his fingertip to reveal a meandering line — a resonator for microwave photons — and pinhead-sized superconducting qubit.
“It’s quantum mechanics on a chip,” says Koch, physics and astronomy and a member of the Center for Applied Physics and Superconducting Technologies (CAPST).
Quantum mechanics is typically associated with microscopic particles, such as atoms, electrons, or photons. However, within the past 20 years the field’s undergone a revolution in how people think about it. As first proposed by Nobel-Prize winning physicist Anthony Leggett, quantum mechanics also applies to macroscopic objects, such as circuits composed of aluminum wires and microwave resonators. As a postdoctoral fellow at Yale, Koch was involved in the discovery of two quantum circuits that are widely used in laboratories around the world, including by researchers at Google, IBM, and many other groups racing to build superconducting-based quantum computers.