title: Consistency of ground state and spectroscopic measurements on flux qubits.
abstract: We compare the results of ground state and spectroscopic measurements carried out on superconducting flux qubits which are effective two-level quantum systems. For a single qubit and for two coupled qubits we show excellent agreement between the parameters of the pseudospin Hamiltonian found using both methods. We argue that by making use of the ground state measurements the Hamiltonian of N coupled flux qubits can be reconstructed as well at temperatures smaller than the energy level separation. Such a reconstruction of a many-qubit Hamiltonian can be useful for future quantum information processing devices.
authors.affiliation: Institute of Photonic Technology, P.O. Box 100239, D-07702 Jena, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Izmalkov
authors.forename: S H W
authors.initials: SH
authors.lastname: van der Ploeg
authors.forename: S N
authors.initials: SN
authors.lastname: Shevchenko
authors.forename: M
authors.initials: M
authors.lastname: Grajcar
authors.forename: E
authors.initials: E
authors.lastname: Il'ichev
authors.forename: U
authors.initials: U
authors.lastname: Hübner
authors.forename: A N
authors.initials: AN
authors.lastname: Omelyanchouk
authors.forename: H-G
authors.initials: HG
authors.lastname: Meyer