Superconductive logic circuits constructed by the use of two thresholds of SQUID

Masahiro Kawai, Yoichiro Sato, Hiroto Kagotani, Takuji Okamoto

Research output: Contribution to journalArticle

Abstract

This paper proposes a method for constructing superconductive logic circuits by actively using two thresholds in a superconducting quantum interference device (SQUID). First, it is demonstrated that the input-output characteristics of a SQUID with multiple inputs can be represented as a two-threshold logic function. Next, a SQUID structure is shown in which all of the input currents have the same significance and the threshold current can be varied without varying the characteristics of the Josephson junction. Each input is weighted by adjusting the internal impedance rather than the input current, and the SQUID thresholds are varied using the value of the steady current applied to an additional input. Finally, it is explained that when logic functions of two to four variables are realized using such SQUIDs, the number of logic functions that can be realized with a single SQUID is much greater than when an existing method is used, and the operating regions are reduced only slightly.

Original languageEnglish
Pages (from-to)42-50
Number of pages9
JournalSystems and Computers in Japan
Volume36
Issue number2
DOIs
Publication statusPublished - Feb 2005

Fingerprint

Quantum Interference
Logic circuits
SQUIDs
Logic
SQUID
Josephson Junction
Threshold logic
Impedance
Internal
Output

Keywords

  • Magnetically coupled superconductive logic circuit
  • SQUID
  • Two-threshold function

ASJC Scopus subject areas

  • Hardware and Architecture
  • Information Systems
  • Theoretical Computer Science
  • Computational Theory and Mathematics

Cite this

Superconductive logic circuits constructed by the use of two thresholds of SQUID. / Kawai, Masahiro; Sato, Yoichiro; Kagotani, Hiroto; Okamoto, Takuji.

In: Systems and Computers in Japan, Vol. 36, No. 2, 02.2005, p. 42-50.

Research output: Contribution to journalArticle

Kawai, Masahiro ; Sato, Yoichiro ; Kagotani, Hiroto ; Okamoto, Takuji. / Superconductive logic circuits constructed by the use of two thresholds of SQUID. In: Systems and Computers in Japan. 2005 ; Vol. 36, No. 2. pp. 42-50.
@article{153b50027d2e4cf780a114cc990de413,
title = "Superconductive logic circuits constructed by the use of two thresholds of SQUID",
abstract = "This paper proposes a method for constructing superconductive logic circuits by actively using two thresholds in a superconducting quantum interference device (SQUID). First, it is demonstrated that the input-output characteristics of a SQUID with multiple inputs can be represented as a two-threshold logic function. Next, a SQUID structure is shown in which all of the input currents have the same significance and the threshold current can be varied without varying the characteristics of the Josephson junction. Each input is weighted by adjusting the internal impedance rather than the input current, and the SQUID thresholds are varied using the value of the steady current applied to an additional input. Finally, it is explained that when logic functions of two to four variables are realized using such SQUIDs, the number of logic functions that can be realized with a single SQUID is much greater than when an existing method is used, and the operating regions are reduced only slightly.",
keywords = "Magnetically coupled superconductive logic circuit, SQUID, Two-threshold function",
author = "Masahiro Kawai and Yoichiro Sato and Hiroto Kagotani and Takuji Okamoto",
year = "2005",
month = "2",
doi = "10.1002/scj.20136",
language = "English",
volume = "36",
pages = "42--50",
journal = "Systems and Computers in Japan",
issn = "0882-1666",
publisher = "John Wiley and Sons Inc.",
number = "2",

}

TY - JOUR

T1 - Superconductive logic circuits constructed by the use of two thresholds of SQUID

AU - Kawai, Masahiro

AU - Sato, Yoichiro

AU - Kagotani, Hiroto

AU - Okamoto, Takuji

PY - 2005/2

Y1 - 2005/2

N2 - This paper proposes a method for constructing superconductive logic circuits by actively using two thresholds in a superconducting quantum interference device (SQUID). First, it is demonstrated that the input-output characteristics of a SQUID with multiple inputs can be represented as a two-threshold logic function. Next, a SQUID structure is shown in which all of the input currents have the same significance and the threshold current can be varied without varying the characteristics of the Josephson junction. Each input is weighted by adjusting the internal impedance rather than the input current, and the SQUID thresholds are varied using the value of the steady current applied to an additional input. Finally, it is explained that when logic functions of two to four variables are realized using such SQUIDs, the number of logic functions that can be realized with a single SQUID is much greater than when an existing method is used, and the operating regions are reduced only slightly.

AB - This paper proposes a method for constructing superconductive logic circuits by actively using two thresholds in a superconducting quantum interference device (SQUID). First, it is demonstrated that the input-output characteristics of a SQUID with multiple inputs can be represented as a two-threshold logic function. Next, a SQUID structure is shown in which all of the input currents have the same significance and the threshold current can be varied without varying the characteristics of the Josephson junction. Each input is weighted by adjusting the internal impedance rather than the input current, and the SQUID thresholds are varied using the value of the steady current applied to an additional input. Finally, it is explained that when logic functions of two to four variables are realized using such SQUIDs, the number of logic functions that can be realized with a single SQUID is much greater than when an existing method is used, and the operating regions are reduced only slightly.

KW - Magnetically coupled superconductive logic circuit

KW - SQUID

KW - Two-threshold function

UR - http://www.scopus.com/inward/record.url?scp=14544306451&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=14544306451&partnerID=8YFLogxK

U2 - 10.1002/scj.20136

DO - 10.1002/scj.20136

M3 - Article

VL - 36

SP - 42

EP - 50

JO - Systems and Computers in Japan

JF - Systems and Computers in Japan

SN - 0882-1666

IS - 2

ER -