Large amplitude driving of a persistent current qubit

In this thesis, the persistent current qubit in the presence of large amplitude microwave radiation is studied. Three main results are presented in this work. A new coherent quasi classical regime has been observed, where coherent quantum dynamics persist even while transitions between energy levels are caused by many photon modes simultaneously. A new theoretical treatment of this regime has been developed, and remarkable agreement between theory and experiment is observed. Also presented is a novel application of strong driving, where unwanted excited state population is cooled to the ground state by utilizing a second avoided crossing. This method of cooling, via a third, ancillary qubit level, is analogous to atomic sideband cooling. Cooling from 400mK to 3mK has been achieved. Finally, a new type of spectroscopy is presented, where an entire manifold of quantum levels is characterized with a single driving frequency, by studying the amplitude dependence of the qubit's behavior. Characterization of energy level spacings reaching 120GHz is achieved with radiation on the order of 0.1GHz.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Physics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2008

Author dc:creator

• Berns, David Marc

Advisor dc:contributor.advisor

• Terry P. Orlando and Mildred S. Dresselhaus.

• 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/1721.1/45451

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/45451