Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Ota, Yukihiro; Nakai, Noriyuki; Nakamura, Hiroki; Machida, Masahiko; Inotani, Daisuke*; Ohashi, Yoji*; Koyama, Tomio*; Matsumoto, Hideki*
Physical Review B, 81(21), p.214511_1 - 214511_6, 2010/06
Times Cited Count：32 Percentile：75.32(Materials Science, Multidisciplinary)An extension of the Ambegaokar-Baratoff relation to a superconductor-insulator-superconductor (SIS) Josephson junction with multiple tunneling channels is derived. Applying the resultant relation to a SIS Josephson junction formed by an iron-based (five-band) and a single-band Bardeen-Cooper-Schrieffer (BCS) type superconductors, a theoretical bound of the Josephson critical current (
) multiplied by the resistance of the junction (
) is given. We reveal that such a bound is useful for identifying the pairing symmetry of iron-pnictide superconductors. One finds that if a measured value of 
is smaller than the bound then the symmetry is 
-wave, and otherwise 
-wave without any sign changes. In addition, we stress that temperature dependence of is sensitive to the difference of the gap functions from the BCS type gap formula in the above heterojunction.
Ota, Yukihiro; Bando, Masamitsu*; Kondo, Yasushi*; Nakahara, Mikio*
no journal, ,
A reliable and stable way to control the temporal behavior of a quantum system are required to realize quantum computing and quantum state engineering. Quantum computing by using holonomy is called holonomic quantum computing, and is expected to be robust against noise and decoherence. In this paper, we propose the holonomic quantum computing in a dimer-chainmodel. The single qubit is represented by two physical particles with spin 1/2. In the dimer, the two physical particles interact with each other through the Ising-type interaction. Thus, the proposal is applicable for various physical systems, e.g., liquid-state NMR and solid-state systems. We exactly construct one- and two-qubit holonomic quantum gates in term of isospectral deformation of the Hamiltonian.
