arXiv subjects

G. Filatrella

Publications and source records attributed to G. Filatrella.

39 records · Page 3Linked to original sources

arXiv1995

Constants of motion in the dynamics of a 2N-junction SQUID

We show that a 2N junction SQUID (Superconducting QUantum Interference Device) made of 2N overdamped, shunted, identical junctions may be described as a system having only 6 degrees of freedom for any N > 2. This is achieved by means of the reduction introduced by Watanabe and Strogatz (Physica D, Vol. 74, (1994) p. 197) for series biased arrays. In our case 6 rather than 3 degrees of freedom are necessary to describe the system, due to the requirement of phase quantization along the superconducting loop constituting the device. Generalization to multijunction parallel arrays is straightforward.

supr-con↗

arXiv1995

Magnetic Field Effect in a Two-dimensional Array of Short Josephson Junctions

We study analytically the effect of a constant magnetic field on the dynamics of a two dimensional Josephson array. The magnetic field induces spatially dependent states and coupling between rows, even in the absence of an external load. Numerical simulations support these conclusions.

chao-dyn↗

arXiv1993

Threshold Analysis for the Inverse ac Josephson Effect

The inverse ac Josephson effect involves rf-induced (Shapiro) steps that cross over the zero-current axis; the phenomenon is of interest in voltage standard applications. The standard analysis of the step height in current, which yields the well-known Bessel-function dependence on an effective ac drive amplitude, is valid only when the drive frequency is large compared with the junction plasma frequency or when the drive amplitude is large compared with the zero-voltage Josephson current. Using a first-order Krylov-Bogoliubov power-balance approach we derive an expression for the threshold value of the drive amplitude for zero-crossing steps that is not limited to the large frequency or large amplitude region. Comparison with numerical solutions of the RSJ differential equation shows excellent agreement for both fundamental and subharmonic steps. The power-balance value for the threshold converges to the Bessel-function value in the high- frequency limit.

chao-dyn↗