Superconducting qubit in a resonator: test of the Leggett-Garg inequality and single-shot readout

September 23 2010
Types d’événements
Thèses ou HDR
Agustín Palacios-Laloy
SPEC Salle Itzykson, Bât.774
23/09/2010
from 14:00

Manuscrit de la thèse / Manuscript of the thesis

This thesis presents a series of experiments in which artificial atoms consisting of superconducting circuits are strongly coupled to the electromagnetic field stored in a microwave resonator, which can be used as a measurement apparatus for the atom.

In a first experiment, we continuously monitored the evolution of a quantum system, we observed the crossover from weak to strong measurement and the freezing of the dynamics by the Quantum Zeno Effect. We probed if the artificial atom complies with the macroscopic realism hypotheses, from which Leggett and Garg have derived a Bell’s inequality in time. In a second experiment, we have demonstrated a high fidelity single-shot qubit readout, a crucial element for quantum processors.