A superconducting flux QuBit : measurement, noise and control

A superconducting quantum bit can be made with three nano-scale Josephson junctions connected in series. In this thesis, various aspects of this qubit are studied. It is shown numerically that the qubit behaves as a giant magnetic dipole with quantum tunneling between the two qubit states. The natural coupling between qubits plus the manipulation on a single qubit state provides the building blocks for universal quantum computing. The state of the qubit can be determined by measuring its flux with a SQUID. The measurement efficiency and measurement-induced decoherence are investigated. A coherent transition assisted scheme is designed for a projective measurement on the qubit. A general method is developed to study qubit decoherence by environmental noise. The dynamic control approach is applied for preventing off-resonant leakage during gate operations and for de-coupling the qubit from noise.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Physics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2002

Author dc:creator

• Tian, Lin, 1971-

Advisor dc:contributor.advisor

• Mildred S. Dresselhaus and Seth Lloyd.

• Physics.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/8483

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/8483