Condensed Matter Seminar Series

Amplifying Quantum Signals with a RF-driven Josephson Oscillator

Michel Devoret

Yale University

Thursday December 4, 1:30 pm, Room 234, Physics Building

Abstract: We have constructed a new type of cryogenic amplifier whose primary purpose is the readout of superconducting quantum bits. It is based on the dynamical switching of an RF-driven Josephson tunnel junction from a low-amplitude to a high-amplitude oscillation state. The external manifestation of this switching is a phase-shift in a pulsed microwave reflection measurement. The main advantages of this new amplifier are speed, high-sensitivity, low back-action, and the absence of on-chip dissipation. We will present the operation of this amplifier and show how it attains the performance predicted by theory.