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Relaxation method in description of RAM memory cell in RSFQ computer

Krzysztof Dominik Pomorski (Faculty of Computer Science, Electronics and Telecommunications, Department of Telecommunications, AGH University of Science and Technology, Cracow, Poland AND Graduate School of Engineering, Department of Quantum Engineering, Nagoya University, Nagoya, Japan)
Hiroyuki Akaike (Graduate School of Engineering, Department of Quantum Engineering, Nagoya University, Nagoya, Japan)
Akira Fujimaki (Graduate School of Engineering, Department of Quantum Engineering, Nagoya University, Nagoya, Japan)
Krzysztof Rusek (Faculty of Computer Science, Electronics and Telecommunications Department of Telecommunications, AGH University of Science and Technology, Cracow, Poland)

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering

ISSN: 0332-1649

Article publication date: 26 November 2018

Issue publication date: 24 January 2019

211

Abstract

Purpose

The lack of reliable and scalable superconducting random access memory (RAM) cells is the main obstacle for full implementation of superconducting rapid single flux quantum(RSFQ) computers. This work points the methodology and the structures that shall be used in future implementation of RSFQ RAM.

Design/methodology/approach

A new design for RAM using two ferromagnetic strips in proximity to the superconductor in a RSFQ computer is presented (1). The concept of using a RAM RSFQ cell as a tuneable superconducting qubit is also explored.

Findings

Two basic architectures for superconducting RAM cells were developed with integration schemes in two dimensions.

Research limitations/implications

The proposed RAM cells as depicted in Figures 7 and 16 offer smaller size and greater 3 scalability in comparison to other suggested schemes (4), (3), (2), (5).

Practical implications

Currently, the main obstacle in implementation of RSQF computer is lack of reliable RAM cell. RSQF computer shall have potential to take a large fraction of classical supercomputers, as it consumes much less power.

Social implications

Computation power shall be cheaper when one uses RSQF computers for big data and computational centres. It is a matter of some time.

Originality/value

The publication presents the new design of superconducting RAM cell for use in RSQF computer. The numerical relaxation method is used to solve biharmonic Ginzburg–Landau equation. The analytic approach as a solution of a specified problem is given.

Keywords

Acknowledgements

This work was funded by Grant JSPS-KAKENHI:26220904. The author would like to thank P.Burset, B.Lu, Y.Tanaka, A.Bednorz, M.Paszynski and P.Peczkowski for their useful discussions and remarks. The work was also supported by the Contract 11.11.230.018. The language corrections were given by John Speller from Lodz University of Technology.

Citation

Pomorski, K.D., Akaike, H., Fujimaki, A. and Rusek, K. (2019), "Relaxation method in description of RAM memory cell in RSFQ computer", COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, Vol. 38 No. 1, pp. 395-414. https://doi.org/10.1108/COMPEL-06-2017-0242

Publisher

:

Emerald Publishing Limited

Copyright © 2018, Emerald Publishing Limited

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