Superconducting flux qubits: Quantum chains and tunable qubits

Superconducting flux qubits: Quantum chains and tunable qubits

Paauw, F.G.

Mooij, J.E. (promotor)
Harmans, C.J.P.M. (promotor)

Applied Sciences

Kavli Institute of Nanoscience Delft

2009-06-18

This thesis presents results of theoretical and experimental work on superconducting persistent-current flux quantum bits. These qubits are promising candidates for the implementation of scalable quantum information processing. This work focuses on the study of one dimensional chains of inductively coupled flux qubits and on qubits with a tunable energy gap. Chains of flux qubits can be used as models of quantum spin chains, one of the most basic systems in many-body physics that has been extensively studied theoretically. The ability to design and tune the qubit and coupling parameters enables exploration of different phase regimes during measurements, in parameter regimes that are not accessible with magnetic materials. The study of the dynamics of quantum waves in an artificial spin chain can also be used to explore novel quantum phenomena with possible applications in quantum computing. Tunability of the minimal energy splitting (the gap) enables one to rapidly bring the flux qubit in and out of resonance with other quantum systems, including a harmonic oscillator. With tunable qubits it also becomes possible to create inter-qubit couplings of different vector nature, using magnetic fluxes. This permits the design of various interaction Hamiltonians for multiple qubit systems. These operations can be performed at the degeneracy point of the qubit, where coherence properties are optimal. Therefore the tunable flux qubit provides an attractive component for the implementation of scalable quantum computation.

Superconducting flux qubits
Josephson junctions
quantum chains

http://resolver.tudelft.nl/uuid:9ed11bb5-0d00-4d33-96f7-b7a6c60d79b2

2009-06-01

9789085930532

Institutional Repository

doctoral thesis

(c) 2009 Paauw, F.G.