195:-based junctions and later switching to lead/niobium junctions. In 1980 the Josephson computer revolution was announced by IBM through the cover page of the May issue of Scientific American. One of the reasons which justified such a large-scale investment lies in that Moore's law - enunciated in 1965 - was expected to slow down and reach a plateau 'soon'. However, on the one hand Moore's law kept its validity, while the costs of improving superconducting devices were basically borne entirely by IBM alone and the latter, however big, could not compete with the whole world of semiconductors which provided nearly limitless resources. Thus, the program was shut down in 1983 because the technology was not considered competitive with standard semiconductor technology. The Japanese
792:
superconductor microprocessor. It's composed of superconducting niobium and relies on hardware components called adiabatic quantum-flux-parametrons (AQFPs). Each AQFP is composed of a few fast-acting
Josephson junction switches, which require very little energy to support superconductor electronics. The MANA microprocessor consists of more than 20,000 Josephson junctions (or more than 10,000 AQFPs) in total.
226:. These advances led to the United States' Hybrid Technology Multi-Threaded project, started in 1997, which sought to beat conventional semiconductors to the petaflop computing scale. The project was abandoned in 2000, however, and the first conventional petaflop computer was constructed in 2008. After 2000, attention turned to
304:
Josephson junctions in RSFQ circuits are biased in parallel. Therefore, the total bias current grows linearly with the
Josephson junction count. This currently presents the major limitation on the integration scale of RSFQ circuits, which does not exceed a few tens of thousands of Josephson junctions
297:
Power is provided by bias currents distributed using resistors that can consume more than 10 times as much static power than the dynamic power used for computation. The simplicity of using resistors to distribute currents can be an advantage in small circuits and RSFQ continues to be used for many
791:
The 2.5 GHz prototype uses 80 times less energy than its semiconductor counterpart, even accounting for cooling … While adiabatic semiconductor microprocessors exist, the new microprocessor prototype, called MANA (Monolithic
Adiabatic iNtegration Architecture), is the world's first adiabatic
117:
computer built in CMOS logic is estimated to consume some 500 megawatts of electrical power. Superconducting logic can be an attractive option for ultrafast CPUs, where switching times are measured in picoseconds and operating frequencies approach 770 GHz. However, since transferring
125:
As superconducting logic supports standard digital machine architectures and algorithms, the existing knowledge base for CMOS computing will still be useful in constructing superconducting computers. However, given the reduced heat dissipation, it may enable innovations such as
378:
On
January 13, 2021, it was announced that a 2.5 GHz prototype AQFP-based processor called MANA (Monolithic Adiabatic iNtegration Architecture) had achieved an energy efficiency that was 80 times that of traditional semiconductor processors, even accounting for the cooling.
80:, to encode, process, and transport data. SFQ circuits are made up of active Josephson junctions and passive elements such as inductors, resistors, transformers, and transmission lines. Whereas voltages and capacitors are important in semiconductor logic circuits such as
118:
information between the processor and the outside world does still dissipate energy, superconducting computing was seen as well-suited for computations-intensive tasks where the data largely stays in the cryogenic environment, rather than
104:
technology. Much of the power consumed, and heat dissipated, by conventional processors comes from moving information between logic elements rather than the actual logic operations. Because superconductors have zero electrical
333:
Efficient single flux quantum (eSFQ) logic is also powered by direct current, but differs from ERSFQ in the size of the bias current limiting inductor and how the limiting
Josephson junctions are regulated.
329:
Efficient rapid single flux quantum (ERSFQ) logic was developed to eliminate the static power losses of RSFQ by replacing bias resistors with sets of inductors and current-limiting
Josephson junctions.
294:, typically by addition of an appropriately sized shunt resistor, to make them switch without a hysteresis. Clocking signals are provided to logic gates by separately distributed SFQ voltage pulses.
313:
Reducing the resistor (R) used to distribute currents in traditional RSFQ circuits and adding an inductor (L) in series can reduce the static power dissipation and improve energy efficiency.
142:
were considered state-of-the-art. Important challenges for the field were reliable cryogenic memory, as well as moving from research on individual components to large-scale integration.
249:, was seen as an opening for superconducting computing research as exascale computers based on CMOS technology would be expected to require impractical amounts of electrical power. The
187:, and within a few years IBM had fabricated the first Josephson junction. IBM invested heavily in this technology from the mid-1960s to 1983. By the mid-1970s IBM had constructed a
412:. There exist three families of superconducting qubits, depending on whether the charge, the phase, or neither of the two are good quantum numbers. These are respectively termed
575:"Superconductivity at IBM – a Centennial Review: Part I – Superconducting Computer and Device Applications, IEEE/CSC & ESAS EUROPEAN SUPERCONDUCTIVITY NEWS FORUM, No. 21"
301:
RSFQ has been used to build specialized circuits for high-throughput and numerically intensive applications, such as communications receivers and digital signal processing.
231:
286:(RSFQ) superconducting logic was developed in the Soviet Union in the 1980s. Information is carried by the presence or absence of a single flux quantum (SFQ). The
179:, but the liquid-helium temperatures and the slow switching time between superconducting and resistive states caused this research to be abandoned. In 1962
502:
343:
250:
109:, little energy is required to move bits within the processor. This is expected to result in power consumption savings of a factor of 500 for an
196:
574:
188:
168:
of standard CMOS technology. As of 2016 there are no commercial superconducting computers, although research and development continues.
779:
200:
375:
Adiabatic
Quantum flux parametron (AQFP) logic was developed for energy-efficient operation and is powered by alternating current.
358:
354:
246:
481:
321:
Reducing the bias voltage in traditional RSFQ circuits can reduce the static power dissipation and improve energy efficiency.
17:
254:
127:
549:
361:, Set/Reset (with nondestructive readout), which together form a universal logic set and provide memory capabilities.
388:
227:
70:
265:
Despite the names of many of these techniques containing the word "quantum", they are not necessarily platforms for
624:"RSFQ logic/memory family: a new Josephson-junction technology for sub-terahertz-clock-frequency digital systems"
727:
848:
838:
833:
740:
715:"Implementation of energy efficient single flux quantum (eSFQ) digital circuits with sub-aJ/bit operation"
49:
switches, and quantization of magnetic flux (fluxoid). As of 2023, superconducting computing is a form of
219:
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signals. RQL gates do not use resistors to distribute power and thus dissipate negligible static power.
843:
701:
688:
528:
853:
283:
278:
215:
623:
449:
161:
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106:
84:, currents and inductors are most important in SFQ logic circuits. Power can be supplied by either
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The primary advantage of superconducting computing is improved power efficiency over conventional
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439:
370:
342:
Reciprocal
Quantum Logic (RQL) was developed to fix some of the problems of RSFQ logic. RQL uses
223:
238:, as well as energy-efficient rapid single flux quantum by Hypres, were seen as major advances.
515:
585:
77:
663:"18-GHz, 4.0-aJ/bit Operation of Ultra-Low-Energy Rapid Single-Flux-Quantum Shift Registers"
8:
409:
394:
347:
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applications where large amounts of information are streamed from outside the processor.
89:
50:
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of SFQ pulses to encode a logical '1'. Both power and clock are provided by multi-phase
287:
242:
110:
46:
704:, IEEE Transactions on Applied Superconductivity, vol.21, no.3, pp.776-779, June 2011.
691:, IEEE Transactions on Applied Superconductivity, vol.21, no.3, pp.760-769, June 2011.
652:, IEEE Transactions on Applied Superconductivity, vol.21, no.3, pp.770-775, June 2011.
626:, IEEE Transactions on Applied Superconductivity, Vol. 1, No. 1, March 1991, pp. 3-28.
475:"An Initial Look at Alternative Computing Technologies for the Intelligence Community"
444:
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66:
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Josephson junctions that were more reliable and easier to fabricate. In 1985, the
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149:
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Superconducting digital logic circuits use single flux quanta (SFQ), also known as
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398:
211:
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649:
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324:
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85:
42:
636:
822:
741:
Superconducting Logic
Circuits Operating With Reciprocal Magnetic Flux Quanta
199:
funded a superconducting research effort from 1981 to 1989 that produced the
148:
is a measure of superconducting circuit or device complexity, similar to the
34:
813:
ExaScale
Computing Study: Technology Challenges in Achieving... Report 2008
529:"Energy-efficient superconducting computing—power budgets and requirements"
413:
27:
Logic circuitry that requires low temperatures to achieve superconductivity
637:"Study of LR-loading technique for low-power single flux quantum circuits"
806:
754:"An adiabatic quantum flux parametron as an ultra-low-power logic device"
429:
678:, IEEE Trans. Appl. Supercond., vol. 23, no. 3, pp. 1701104, June 2013.
434:
417:
38:
611:"Cold numbers: Superconducting supercomputers and presumptive anomaly"
573:
Gallagher, William J.; Harris, Erik P.; Ketchen, Mark B. (July 2012).
610:
401:
207:
54:
780:"Superconducting Microprocessors? Turns Out They're Ultra-Efficient"
613:, Industrial and Corporate Change, vol. 29, no. 2, pp.485-505, 2020.
298:
applications where energy efficiency is not of critical importance.
393:
Superconducting quantum computing is a promising implementation of
172:
131:
119:
743:, University of Maryland, Department of Physics, PhD dissertation.
408:. As in a superconducting electrode, the phase and the charge are
257:'s research and development efforts in superconducting computing.
164:
since the mid-1950s. However, progress could not keep up with the
473:
Joneckis, Lance; Koester, David; Alspector, Joshua (2014-01-01).
160:
Superconducting computing research has been pursued by the U. S.
135:
480:. Institute for Defense Analyses. pp. 15–16, 24–25, 47–50.
134:, it is harder to reduce their size. As of 2014, devices using
139:
58:
648:
Ortlepp T, Wetzstein O, Engert S, Kunert J, Toepfer H (2011).
639:, IEEE Trans. Appl. Supercond., vol.17, pp.150–153, June 2007.
550:"Will the NSA Finally Build Its Superconducting Spy Computer?"
676:"Low-Energy Consumption RSFQ Circuits Driven by Low Voltages"
114:
661:
Tanaka M, Ito M, Kitayama A, Kouketsu T, Fujimaki A (2012).
531:, IEEE Trans. Appl. Supercond., vol. 23, 1701610, June 2013.
325:
Energy-Efficient Single Flux Quantum Technology (ERSFQ/eSFQ)
113:. For comparison, in 2014 it was estimated that a 1 exa
53:, as superconductive electronic circuits require cooling to
674:
Tanaka M, Kitayama A, Koketsu T, Ito M, Fujimaki A (2013).
609:
N. De Liso, G. Filatrella, D. Gagliardi, C. Napoli (2020).
364:
192:
101:
81:
650:"Reduced Power Consumption in Superconducting Electronics"
752:
Takeuchi N, Ozawa D, Yamanashi Y and Yoshikawa N (2013).
713:
Volkmann MH, Sahu A, Fourie CJ, and Mukhanov OA (2013).
702:"Zero Static Power Dissipation Biasing of RSFQ Circuits"
472:
171:
Research in the mid-1950s to early 1960s focused on the
572:
767:"Energy efficiency of adiabatic superconductor logic"
726:
Herr QP, Herr AY, Oberg OT, and Ioannidis AG (2011).
260:
203:, which was a 4-bit machine with 1,000 bits of RAM.
57:
temperatures for operation, typically below 10
730:, J. Appl. Phys. vol. 109, pp. 103903-103910, 2011.
584:. IEEE Council on superconductivity. Archived from
272:
689:"Energy-Efficient Single Flux Quantum Technology"
635:Yamanashi Y, Nishigai T, and Yoshikawa N (2007).
337:
820:
769:, Supercond. Sci. Technol. 28 015003, Jan. 2015.
765:Takeuchi N, Yamanashi Y and Yoshikawa N (2015).
700:DE Kirichenko, S Sarwana, AF Kirichenko (2011).
251:Intelligence Advanced Research Projects Activity
382:
245:beginning in the mid-2010s, as codified in the
138:as the superconducting material operating at 4
694:
809:, NSA, 2005 - Promoted RSFQ R&D projects.
316:
45:, including zero-resistance wires, ultrafast
759:
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717:, Supercond. Sci. Technol. 26 (2013) 015002.
707:
681:
629:
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253:, formed in 2006, currently coordinates the
197:Ministry of International Trade and Industry
152:used for semiconductor integrated circuits.
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616:
527:Holmes DS, Ripple AL, Manheimer MA (2013).
218:logic scheme, which had improved speed and
191:using these junctions, mainly working with
189:superconducting quantum interference device
668:
665:, Jpn. J. Appl. Phys. 51 053102, May 2012.
655:
603:
505:, IEEE Spectrum, vol. 48, pp. 48–54, 2011.
733:
720:
521:
130:of components. However, as they require
69:, with an important application known as
495:
397:technology that involves nanofabricated
365:Adiabatic Quantum Flux Parametron (AQFP)
247:National Strategic Computing Initiative
95:
14:
821:
728:"Ultra-low-power superconductor logic"
807:Superconducting Technology Assessment
756:, Supercond. Sci. Technol. 26 035010.
547:
516:"Superconductor Logic Goes Low-Power"
92:, depending on the SFQ logic family.
772:
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222:, was developed by researchers at
183:established the theory behind the
41:that use the unique properties of
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484:from the original on June 4, 2016
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389:Superconducting quantum computing
261:Conventional computing techniques
228:superconducting quantum computing
71:superconducting quantum computing
622:Likharev KK, Semenov VK (1991).
273:Rapid single flux quantum (RSFQ)
815:, "6.2.4 Superconducting Logic"
566:
548:Brock, David C. (2016-04-24).
338:Reciprocal Quantum Logic (RQL)
13:
1:
518:, IEEE spectrum, 22 June 2011
455:
383:Quantum computing techniques
255:U. S. Intelligence Community
230:. The 2011 introduction of
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10:
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317:Low Voltage RSFQ (LV-RSFQ)
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128:three-dimensional stacking
353:Major RQL gates include:
284:Rapid single flux quantum
279:Rapid single flux quantum
216:Rapid single flux quantum
63:superconducting computing
450:Unconventional computing
232:reciprocal quantum logic
162:National Security Agency
146:Josephson junction count
440:Quantum flux parametron
371:Quantum flux parametron
224:Moscow State University
166:increasing performance
420:, and hybrid qubits.
33:refers to a class of
31:Superconducting logic
18:Superconducting logic
687:Mukhanov OA (2011).
514:Courtland R (2011).
96:Fundamental concepts
78:magnetic flux quanta
849:Digital electronics
839:Quantum electronics
834:Integrated circuits
591:on 24 December 2022
503:"The tops in flops"
410:conjugate variables
406:Josephson junctions
395:quantum information
348:alternating current
288:Josephson junctions
234:by Quentin Herr of
90:alternating current
51:cryogenic computing
243:exascale computing
47:Josephson junction
844:Superconductivity
739:Oberg OT (2011).
445:Superconductivity
292:critically damped
267:quantum computing
220:energy efficiency
177:Dudley Allen Buck
111:exascale computer
67:quantum computing
16:(Redirected from
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430:Beyond CMOS
418:flux qubits
39:logic gates
823:Categories
786:2021-05-25
559:2016-04-21
488:2016-04-22
456:References
435:Logic gate
402:electrodes
107:resistance
208:Bell Labs
206:In 1983,
132:inductors
55:cryogenic
482:Archived
424:See also
173:cryotron
120:big data
61:. Often
595:10 June
309:LR-RSFQ
201:ETL-JC1
156:History
136:niobium
59:kelvin
589:(PDF)
578:(PDF)
478:(PDF)
359:AnotB
355:AndOr
115:FLOPS
597:2023
290:are
193:lead
102:CMOS
82:CMOS
88:or
37:or
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