Non-Linear Wave Phenomena in Josephson Elements for Superconducting Electronics

Non-Linear Wave Phenomena in Josephson Elements for Superconducting Electronics
Author: P. L. Christiansen
Publisher:
Total Pages: 80
Release: 1985
Genre:
ISBN:

The long and intermediate length Josephson tunnel junction oscillator with overlap geometry of linear and circular configuration, is investigated by computational solution of the perturbed sine-Gordon equation model and by experimental measurements. The model predicts the experimental results very well. Line oscillators as well as ring oscillators are treated. For long junctions soliton perturbation methods are developed and turn out to be efficient prediction tools, also providing physical understanding of the dynamics of the oscillator. For intermediate length junctions expansions in terms of linear cavity modes reduce computational costs. The narrow linewidth of the electromagnetic radiation (typically 1 kHz of a line at 10 GHz) is demonstrated experimentally. Corresponding computer simulations requiring a relative accuracy of less than 10 to the -7th power are performed on supercomputer CRAY-1-S. The broadening of linewidth due to external microradiation and internal thermal noise is determined. Keywords include: Cavity mode; Chaos; Fiske steps; Hysteresis; Intermittency, Josephson fluxon oscillator; Josephson ring oscillator; Josephson tunnel junction; Noise rise; Perturbation theory; Radiation line-width; Sine-Gordon equation (perturbed); Solition (fluxon); SQUID; Subharmonics; and Zero field stages.

Nonlinear Superconductive Electronics and Josephson Devices

Nonlinear Superconductive Electronics and Josephson Devices
Author: G. Costabile
Publisher: Springer Science & Business Media
Total Pages: 439
Release: 2012-12-06
Genre: Science
ISBN: 1461538521

The on-going developments, and the recent achievements of the superconducting electronics (especially in the field of Josephson junctions and the inherent nonlinear dynamics) inspired us to organize a conference where different groups working on the subject could meet and discuss the latest results of their investigations. This idea was realized as two joint workshops, the NATO Advanced Research Workshop on Superconducting Electronics with Prof. N.F. Pedersen as chairman, and the 2nd Workshop on Josephson Devices, with Profs. G. Costabile and M. Russo as chairmen, held in Capri, Italy on September 3-7, 1990. The Workshops were very successful. About 70 scientists from 12 countries (Denmark, France, Germany, Greece, Italy, Japan, People's Republic of China, Sweden, United Kingdom, USA, USSR, and Venezuela) enjoyed the many interesting and mostly informal occasions for scientific exchanges as well as the very pleasant weather of Southern Italy. We are very grateful to the Institutions which made possible the realization and the success of the conference with their financial support : NATO Science Committee through the NATO International Scientific Exchange Programmes, University of Salerno, and Istituto di Cibernetica of the Consiglio Nazionale delle Ricerche (C.N.R.) of Italy. The conference was held under the auspices of the Progetto Finalizzato "Superconductive and Cryogenic Technologies" of C.N.R. Finally special thanks go to our Conference Secretary Anna Maria Mazzarella for carrying out most of the organizative work, and for her continuous "on stage" support in solving all the problems which inevitably arise in such occasions.

Research in Progress

Research in Progress
Author: United States. Army Research Office
Publisher:
Total Pages: 284
Release: 1984
Genre: Military research
ISBN:

Vols. for 1977- consist of two parts: Chemistry, biological sciences, engineering sciences, metallurgy and materials science (issued in the spring); and Physics, electronics, mathematics, geosciences (issued in the fall).

Decoherence and Time-Resolved Readout in Superconducting Quantum Circuits (Dekohärenz und Zeitaufgelösste Quantenmessung in Supraleitenden Schaltkreisen)

Decoherence and Time-Resolved Readout in Superconducting Quantum Circuits (Dekohärenz und Zeitaufgelösste Quantenmessung in Supraleitenden Schaltkreisen)
Author: Georg M. Reuther
Publisher: Logos Verlag Berlin GmbH
Total Pages: 158
Release: 2011
Genre: Computers
ISBN: 3832528466

Superconducting quantum circuits are promising candidates for solid-state based quantum computation. However, minimizing dissipation caused by external noise sources remains a tough challenge. Here, we present an analytic dissipative theory for a complex circuit of two resonators coupled via a flux qubit. In this 'quantum switch', the qubit acts as a tunable coupler between the resonators, which enables switching their interaction on and off. A natural application of this setup is to create entangled two-resonator states. However, it turns out that, even if the qubit has no dynamics, qubit dissipation affects the resonators to a considerable degree. For successful quantum information processing, it is desirable to demonstrate the coherence of qubit time evolution in single-shot experiments without too much backaction on the qubit. In the second part of this thesis, we present a novel scheme for a time-resolved single-run measurement of coherent qubit dynamics. For a charge qubit probed by a weak high-frequency signal, we find that the reflected outgoing signal possesses a time-dependent phase shift that is proportional to a qubit observable. A similar approach is presented for a flux qubit coupled to a resonantly driven high-frequency oscillator, which serves as a meter device for monitoring the time-resolved qubit dynamics.