Measurement back action and feedback in superconducting circuits

Philippe Campagne-Ibarcq 1, 2
1 QUANTIC - QUANTum Information Circuits
ENS Paris - École normale supérieure - Paris, Inria Paris-Rocquencourt, UPMC - Université Pierre et Marie Curie - Paris 6, MINES ParisTech - École nationale supérieure des mines de Paris, CNRS - Centre National de la Recherche Scientifique : UMR8551
Abstract : This thesis presents a series of experiments highlighting measurement back action and decoherence in a basic open quantum system, the superconducting qubit. These observations are enabled by recent advances in amplification close to the quantum limit using Josephson circuits. The information extracted from the system can then be used as input in quantum feedback. A stroboscopic projective readout is performed and a feedback loop is used to correct for detected errors, thus stabilizing an arbitrary predetermined state of the qubit. When monitoring continuously the environment of the qubit by heterodyne detection of its fluorescence, we reconstruct individual quantum trajectories during relaxation. Conditioning this detection to the outcome of a following projective measurement, we access the weak values of the fluorescence signal. Included in a continuous feedback loop, this detection is also used to stabilize an arbitrary state of the qubit. Finally, a last experiment witnesses quantum Zeno dynamics of a resonant microwave mode, entailed by its coupling to the qubit.
Document type :
Complete list of metadatas
Contributor : Philippe Campagne-Ibarcq <>
Submitted on : Monday, December 28, 2015 - 6:10:57 PM
Last modification on : Tuesday, May 14, 2019 - 10:12:19 AM


Files produced by the author(s)


Public Domain


  • HAL Id : tel-01248789, version 1


Philippe Campagne-Ibarcq. Measurement back action and feedback in superconducting circuits. Quantum Physics [quant-ph]. Ecole Normale Supérieure (ENS), 2015. English. ⟨tel-01248789⟩



Record views


Files downloads