Coherent control of dipolar coupled spins in large Hilbert spaces

Controlling the dynamics of a dipolar-coupled spin system is critical to the development of solid-state spin-based quantum information processors. Such control remains challenging, as every spin is coupled to a large number of surrounding spins. In this thesis, we primarily focus on developing coherent control techniques for such large spin systems. We start by experimentally simulating spin squeezing using a liquid-state NMR quantum information processor. We demonstrate that the precision of quantum control obtained using strongly modulating pulses was sufficient to reproduce the theoretically expected behavior of the spin observables and the associated entanglement measures among the underlying qubits. We then investigate coherent control in a more complex solid-state spin system consisting of an ensemble of spin pairs. Using pulse amplitude modulation techniques, we decouple the weaker interactions between different pairs and extend the coherence lifetimes within the two-spin system. This is achieved without decoupling the stronger interaction between the two spins within a pair. We thus demonstrated that it is possible to restrict the evolution of a dipolar coupled spin network to a much smaller subspace of the system Hilbert space which allows us to significantly extend the phase coherence times for selected states. Finally, we demonstrate the sensitivity of highly correlated multiple-quantum states to the presence of rare spin defects in a solid-state spin system.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Nuclear Science and Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2006

Author dc:creator

• Sinha, Suddhasattwa

Advisor dc:contributor.advisor

• David G. Cory.

• Nuclear Science and Engineering.

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/1721.1/41278

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/41278