Computational and Mathematical Modeling of Coupled Superconducting Quantum Interference Devices

Steven M. Anton, Shane A. Cybart, Stephen Wu +2 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.

Keiji Enpuku, Keiji Yoshida

In order to study the effect of a multiturn input coil on superconducting quantum interference device (SQUID) characteristics, the radio frequency (rf) properties of the coupling circuit between the SQUID coil and the input coil are studied. For the measurement of rf properties of the coupling circuit, the so-called expanded model of the coupling circuit using normal metals was adopted, which is shown to be very useful for this purpose. It is shown that the SQUID coil cannot be expressed by a simple inductance when the SQUID coil is coupled to the input coil, i.e., many resonant structures are observed in rf properties of the coupling circuit. It is also shown that the damping resistance is useful in suppressing the resonant structures. Using the experimental results, a circuit model of the SQUID coupled to the multiturn input coil is proposed.

F. Chiarello

E. Sarnelli, Consiglio Nazionale, Complesso Universitario +1 more

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.