State Purification and Decoherence Suppression by Continuous Measurement of a Qubit
Abstract
The main goal of the project was to study theoretically the process of continuous measurement and feedback control of solid-state qubits, and to analyze possible use of quantum feedback for decoherence suppression. This initial goal has been somewhat extended in the course of the project and also included theoretical analysis of the RF-SET operation and close collaboration with experimental group at JPL on superconducting qubits. The obtained results have been published in 9 journal papers (2 more submitted) and 7 conference proceedings and book chapters. 1) We have developed the theory of continuous measurement of solid-state qubits and applied it to various setups, including entangled qubits, nanomechanical resonators, realistic nonideal detectors, and quadratic detectors. We have studied one-qubit quantum feedback and calculated the degree of decoherence suppression and state purification provided by the feedback. We have shown that the qubits can be made almost 100% entangled by continuous measurement, in spite of external decoherence. Several experiments have been proposed. 2) We have developed the theory of the response and sensitivity of the normal-metal RF-SET with realistically large Q-factor, and also proposed a new operation mode of the RF-SET. 3) We have been involved in collaboration with experimental group of Dr. Echternach (JPL) on observation of Rabi oscillations in the single-Cooper-pair-box qubit. Our contribution included development of the computer code for fining experimental results, geometrical modeling of the sample design using FASTCAP, and theoretical support in a course of experiment.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 17, 2004
- Accession Number
- ADA427409
Entities
People
- Alexander Korotkov
Organizations
- University of California, Riverside