Realization of a classical counterpart of a scalable design for adiabatic quantum computation

We implement a classical counterpart of a scalable design for adiabatic quantum computation. The key element of this design is a coupler providing controllable coupling between two bistable elements (in our case superconducting rings with a single Josephson junction playing the role of a classical counterpart of superconducting flux qubits) The coupler is also a superconducting ring with a single Josephson junction that operates in the non-hysteretic mode. The flux coupling between two bistable rings can be controlled by changing the magnetic flux through the coupler. Thereby, the coupling can be tuned from ferromagnetic trough zero to to anti-ferromagnetic.Comment: 3 pages, 3 figures v2: extended discussion experimental result

Anomalous Periodicity of the Current-Phase Relationship of Grain-Boundary Josephson Junctions in High-Tc Superconductors

The current-phase relation (CPR) for asymmetric 45 degree Josephson junctions between two d-wave superconductors has been predicted to exhibit an anomalous periodicity. We have used the single-junction interferometer to investigate the CPR for this kind of junctions in YBCO thin films. Half-fluxon periodicity has been experimentally found, providing a novel source of evidence for the d-wave symmetry of the pairing state of the cuprates.Comment: 4 pages, 5 figure

High Tc SQUIDs for Unshielded Measuring in Disturbed Environments

Directly coupled dc SQUID gradiometers on the basis of YBa2Cu3O7-x for unshielded NDE measurements are investigated. The influence of different SQUID layout parameters on the field sensitivity is shown. A sensitivity of 500 fT/(cm.√Hz) is achieved with a baseline of 3.6 mm. A slit in an aluminium plate was detected in an demonstration of NDE in 1 cm depth with eddy current method

Superconducting bolometer array with SQUID readout for submillimetre wavelength detection

We have tested a fully microfabricated superconducting bolometer array for astrophysical observations at submillimetre wavelengths. The system is cooled by a He-3 sorption refrigerator operating in a pumped 4 He cryostat. The transition edge bolometer uses a bilayer of molybdenum and a gold-palladium alloy with a transition temperature of around 500 mK as the thermometer. The bolometer is voltage biased, and the current is measured by a superconducting quantum interference device (SQUID) ammeter