Quantum computing with superconducting quantum interference devices: a possible strategy

He-Liang Huang, Dachao Wu, Daojin Fan +1 more

P. Carelli, Vittorio Foglietti

Measurements of low inductance dc superconducing quantum interference devices (SQUIDs) are presented. The SQUIDs used for such measurements are made using a photolithographic technique similar to that one developed by IBM for the superconducting computer. On the same chip a coil is evaporated with a coupling coefficient k to the SQUID larger than 0.33. The best measured intrinsic energy sensitivity is 4 h. Possible improvements in the design are proposed.

Frank K. Wilhelm, Kouichi Semba

C. Cosmelli, F. Sciamanna, Maria Gabriella Castellano +4 more

The flux states of a rf superconducting quantum interference device (SQUID) can be used to investigate macroscopic quantum effects, the most challenging of which is the detection of quantum coherent oscillations, and are promising candidates for the implementation of quantum computing. The use of a proper readout system is of utmost importance for these purposes. In this letter we present experimental evidence of the possibility of using an underdamped, hysteretic dc SQUID to read out stroboscopically the flux states of a rf SQUID, allowing a single shot discrimination with an efficiency of 98%. The devices are all integrated on chip.

James F. Annett, Balazs L. Gyorffy, Timothy P. Spiller

Peng Zhang, Z. D. Wang, J. D. Sun +1 more

We propose a different scheme to realize holonomic quantum computation with rf superconducting quantum interference device (SQUID) qubits in a microwave cavity. In this scheme associated with the non-Abelian holonomies, the single-qubit gates and a two-qubit controlled-PHASE gate as well as a controlled-NOT gate can be easily constructed by tuning adiabatically the Rabi frequencies of classical microwave pulses coupled to the SQUIDs. The fidelity of these gates is estimated to be possibly higher than 90% with the current technology.