Dissertation/Thesis Abstract

Quantum Trajectories of a Superconducting Qubit
by Weber, Steven Joseph, Ph.D., University of California, Berkeley, 2014, 147; 3686046
Abstract (Summary)

In quantum mechanics, the process of measurement is intrinsically probabilistic. As a result, continuously monitoring a quantum system will randomly perturb its natural unitary evolution. An accurate measurement record documents this stochastic evolution and can be used to reconstruct the quantum trajectory of the system state in a single experimental iteration. We use weak measurements to track the individual quantum trajectories of a superconducting qubit that evolves under the competing influences of continuous weak measurement and Rabi drive. We analyze large ensembles of such trajectories to examine their characteristics and determine their statistical properties. For example, by considering only the subset of trajectories that evolve between any chosen initial and final states, we can deduce the most probable path through quantum state space. Our investigation reveals the rich interplay between measurement dynamics, typically associated with wavefunction collapse, and unitary evolution. Our results provide insight into the dynamics of open quantum systems and may enable new methods of quantum state tomography, quantum state steering through measurement, and active quantum control.

Indexing (document details)
Advisor: Siddiqi, Irfan
Commitee: Clarke, John, Salahuddin, Sayeef
School: University of California, Berkeley
Department: Physics
School Location: United States -- California
Source: DAI-B 76/08(E), Dissertation Abstracts International
Subjects: Quantum physics, Atomic physics
Keywords: Microwave engineering, Quantum computing, Quantum information, Quantum measurement, Quantum optics, Superconducting qubits
Publication Number: 3686046
ISBN: 978-1-321-62658-2
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