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Flux Noise due to Spins in SQUIDs

Superconducting Quantum Interference Devices (SQUIDs) are currently being used as flux qubits and read-out detectors in a variety of solid-state quantum computer
architectures. The main limitation of SQUID qubits is that they have a coherence time of the order of 10 us, due to the presence of intrinsic flux noise that is not yet fully understood. The origin of flux noise is currently believed to be related to spin impurities
present in the materials and interfaces that form the device. Here we present a novel numerical method that enables calculations of the flux produced by spin impurities even when they are located quite close to the SQUID wire. We show that the SQUID will be particularly sensitive to spins located at its wire edges, generating flux shifts of up to 4 nano flux quanta, much higher than previous calculations based on the software
package FastHenry. This shows that spin impurities in a particular region along the wire's
surface play a much more important role in producing flux noise than other spin impurities located elsewhere in the device. / Graduate / 0611 / 0607 / 0753 / laforest@uvic.ca

Identiferoai:union.ndltd.org:uvic.ca/oai:dspace.library.uvic.ca:1828/4810
Date20 August 2013
CreatorsLaForest, Stephanie
ContributorsDe Sousa, RogeĢrio Costa Reis
Source SetsUniversity of Victoria
LanguageEnglish, English
Detected LanguageEnglish
TypeThesis
RightsAvailable to the World Wide Web

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