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dc.contributor.advisorHan, Siyuan
dc.contributor.authorMao, Bo
dc.date.accessioned2011-04-26T03:18:27Z
dc.date.available2011-04-26T03:18:27Z
dc.date.issued2010-09-12
dc.date.submitted2010
dc.identifier.otherhttp://dissertations.umi.com/ku:11154
dc.identifier.urihttp://hdl.handle.net/1808/7429
dc.description.abstractA radio frequency (rf) superconducting quantum interference device (SQUID) is a macroscopic quantum object consisting of a superconducting loop interrupted by a Josephson junction. Superconducting phase quantum bits (qubits) based on rf SQUIDs have been proven to be one of the most promising candidates for building a quantum computer. They exploit the unique resources of quantum superposition and entanglement and are exponentially faster than classical computers in solving certain problems, such as factoring. Compared to other approaches to quantum computing, superconducting phase qubits allow stronger and more flexible inter-qubit coupling and thus are easier to scale up. However, phase qubits couple to the environment and are subject to considerable decoherence. The resulting coherence time (also called decoherence time) is on the order of 100 ns, about two orders of magnitude shorter than that required for fault-tolerant quantum computing. One possible solution is to develop faster quantum gates in phase qubits. In this dissertation, coherent manipulation of multi-partite quantum states via Landau-Zener (LZ) transitions was investigated in a phase qubit, which was coupled to two microscopic two-level systems (TLSs) embedded in the tunnel barrier of the Josephson junction. The qubit chip was measured at temperatures below 30 mK in an ultra-low noise environment with excellent electrical and magnetic filtering and shielding. All parameters of the phase qubit were calibrated independently. The phase qubit's decoherence times have been carefully measured as well. Fast and precise coherent control of the tripartite quantum states has been successfully demonstrated by the observation of the Landau-Zener-Stückelberg (LZS) interference in the coupled qubit-TLS system. Furthermore, it is shown that utilizing LZ transitions to create multi-partite entangled states, such as the W state, is significantly more efficient than conventional methods which require a sequence of single-qubit and two-qubit gates. Hence, coherent manipulation of multi-partite quantum states via LZ transitions is a promising basis for a new family of fast multi-qubit quantum gates.
dc.format.extent95 pages
dc.language.isoen
dc.publisherUniversity of Kansas
dc.rightsThis item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
dc.subjectCondensed matter physics
dc.subjectCoherent control
dc.subjectLz transition
dc.subjectQubit-tls
dc.subjectRf squid phase qubit
dc.subjectTri-partite quantum system
dc.titleCoherent Manipulation of Multi-Partite Quantum States in a Qubit-TLS System via Landau-Zener Transition
dc.typeDissertation
dc.contributor.cmtememberMarfatia, Danny
dc.contributor.cmtememberWu, Judy
dc.contributor.cmtememberZhao, Hui
dc.contributor.cmtememberHui, Rongqing
dc.thesis.degreeDisciplinePhysics & Astronomy
dc.thesis.degreeLevelPh.D.
kusw.oastatusna
kusw.oapolicyThis item does not meet KU Open Access policy criteria.
dc.rights.accessrightsopenAccess


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