Dr. R. Vijayaraghavan

The Nobel Prize in Physics for 2025 has been awarded to John Clarke, Michel Devoret, and John Martinis for conducting a series of experiments that demonstrated quantum tunneling and energy quantization in a “macroscopic” electrical circuit for the first time. In this talk, I will explain the experiments they conducted using a superconducting electrical circuit element called a Josephson junction. I will illustrate how this experiment was a master stroke in both the choice of the system and the clever engineering used to sufficiently isolate it from its environment, enabling the observation of quantum effects. These early experiments set the stage for the development of quantum bits using superconducting circuits, a leading architecture for building practical quantum computers. Since one of the laureates, Michel Devoret, is also my PhD advisor, I hope to share some anecdotes and my own experience working with him, including an experiment very closely related to the one recognized by this year’s Nobel Prize in Physics.