PHYSICS COLLOQUIUM
Speaker: Dr. A. Wallraff (Yale)
Date: Wednesday, December 15, 2004
Time: 16:45 h (coffee/tea at 16:15 h in front of auditorium)
Place: ETH Hönggerberg, HPV G4
Title: Circuit Quantum Electrodynamics: Doing Quantum Optics with Superconductors
Abstract:
I will describe recent experiments in which the strong coupling limit of cavity quantum electrodynamics has been realized for the first time using superconducting circuits [1]. In our approach, we use a Cooper-pair box as an artificial atom, which is coupled to a one-dimensional cavity formed by a transmission line resonator. In the case when the Cooper-pair box qubit is tuned into resonance with the cavity, we observe the vacuum Rabi splitting of the cavity mode, indicating that the strong coupling regime is attained, and coherent superpositions between the qubit and a single photon are generated. When the qubit is detuned from the cavity resonance frequency, we perform high-fidelity dispersive quantum non-demolition readout of the qubit state. Using this readout technique, we have characterized the qubit properties spectroscopically, performed Rabi oscillations of the qubit, and attained coherence times greater than 500 ns, indicating that this architecture is extremely attractive for quantum computing and control [2]. [1] A. Wallraff, D. I. Schuster, A. Blais, L. Frunzio, R.-S. Huang, J. Majer, S. Kumar, S. M. Girvin and R. J. Schoelkopf Nature (London) 431, 162 (2004) [2] A. Blais, R.-S. Huang, A. Wallraff, S. M. Girvin and R. J. Schoelkopf Phys. Rev. A 69, 062320 (2004)