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Superconducting Microprocessors? Turns Out They're Ultra-Efficient (2021)
- wizardforhire 2y agoAnother notch on the belt for a cryocooler boom. Oh “superconducting is hard”, “if only we had high temperature superconductors”. All valid, but if we work with what we got and disrupt cyrocoolers make them a commodity like magnetrons all those laments become moot. Prove me wrong.
- Terr_ 2y agoSo someone else needs to prove a negative, that there exists no possible technology that will "disrupt" cryocoolers by bringing them to an unspecified price/performance point by an unspecified time in the future to service an unspecified computing use-case? That seems more than a little unfair. :p
- JumpCrisscross 2y ago> someone else needs to prove a negative, that there exists no possible technology that will "disrupt" cryocoolers Look at the Wikipedia references for crycoolers [1]. Note the dates and volume. Now look at room-tempuerature superconductors [2]. 1990 vs 2023. 5 vs 57. OP is arguing that a greater fraction of high-temperature superconducting research dollars might find purchase in improving the cryocooler than we presently spend. [1] https://en.wikipedia.org/wiki/Cryocooler#References https://en.wikipedia.org/wiki/Cryocooler#References [2] https://en.wikipedia.org/wiki/Room-temperature_superconductor#References https://en.wikipedia.org/wiki/Room-temperature_superconducto...
- Terr_ 2y ago> Now look at room-tempuerature superconductors [2]. As a tangent: Don't forget to look at pressures too. Some newer superconductors that are near-room-temperature aren't quite as exciting when it turns out that requires over 1.5 million times normal atmospheric pressure. ("Hey, I think I over-tightened the CPU heatsink...") Ex: https://en.wikipedia.org/wiki/Lanthanum_decahydride https://en.wikipedia.org/wiki/Lanthanum_decahydride
- tliltocatl 2y agoThe problem is, cryocooler theory is pretty well established and "solved at this point, so there is no reason to expect something completely new phenomena there, just some engineering improvements. Solid-state physics, on the other hand, is just computationally infeasible to "solve", so there is a plenty of possibility to discover something unpredicted.
- JumpCrisscross 2y ago> cryocooler theory is pretty well established and "solved at this point What are you quoting? What is "cryocooler theory"?
- tliltocatl 2y agoThermodynamics. Should have been "solved", missed the closing parenthesis.
- coryrc 2y agoThe latter aren't being researched for CPUs, which are small things. They're for applications like long-distance power transmission, electric motors, and more. Things which aren't feasible to cryocool.
- Terr_ 2y ago> long-distance power transmission IIRC unlikely to change quickly even with higher-temp superconductors, since it would mean splicing in new power-grid segments that transfer direct-current instead of alternating, and then you have losses in conversion too.
- coryrc 2y agoWe have plenty of long-distance HVDC links, one of the most prominent being https://en.wikipedia.org/wiki/Quebec_%E2%80%93_New_England_Transmission https://en.wikipedia.org/wiki/Quebec_%E2%80%93_New_England_T..., which also helped isolate Quebec from the Northeast blackout of 2003 https://en.wikipedia.org/wiki/Northeast_blackout_of_2003 https://en.wikipedia.org/wiki/Northeast_blackout_of_2003
- XorNot 2y agoAlso notable because heat rejection on that scale till you enter the superconducting regime is a reinforcing loop: the device no longer makes heat, you just need to keep the environmental heat out.
- jon_richards 2y agoAnd the power requirement to maintain temperature scale by surface area, not volume. Same reason thermal power storage using giant piles of sand is theoretically viable.
- yeknoda 2y agoIs the cost of cryocoolong capex or Opex dominated?
- deleted 2y ago[deleted]
- hn72774 2y agoAre you referring to the hardware cost vs operating cost? Or how the units are financed?
- idiotsecant 2y agoThat's what it means. Some things are expensive to buy, some things are expensive to run, and some things are both.
- hn72774 2y agoThe terms in that context are fixed cost vs variable cost. CapEx vs OpEx deals with how the equipment is managed financially. Buy vs lease/rent/IAAS. Good examples here https://centersquaredc.com/blog/choosing-the-best-data-center-strategy-is-capex-or-opex-right-for-you https://centersquaredc.com/blog/choosing-the-best-data-cente...
- tuatoru 2y agocapex = capital expenditure; opex = operational expenditure. There's some theorem about investments that says it doesn't matter how they are financed. A good one is good, and a bad one is bad, whether or not you use debt.
- actinium226 2y agoI'll bet you I can find a way to finance a good deal that turns it into a bad one. The other way around seems harder.
- marcosdumay 2y ago
- nine_k 2y agoWould running a cryocooler spend more energy than a superconducting CPU / GPU would save?
- moralestapia 2y ago>The 2.5 GHz prototype uses 80 times less energy than its semiconductor counterpart, even accounting for cooling It's in the header of the article.
- hypercube33 2y agoThe way it reads though is that the chip itself uses less power but still needs to be cooled which takes a lot of energy (traditionally)
- moralestapia 2y ago>even accounting for cooling No.
- Grimblewald 2y agostuff like this makes me wonder what the distribution on human context limits is.
- jasonwatkinspdx 2y agoI'm fond of this argument but I would point out that magnetrons are remarkably simple devices once you figure out how the waves are interacting.
- tarikjn 2y agoI’ve been thinking about making cheaper cryocoolers for CO2 condensation. I’d love to hear your perspective on other applications :)
- d_silin 2y agoA more recent take on this subject: https://diginomica.com/superconducting-chips-could-pack-data-center-shoebox-heres-how https://diginomica.com/superconducting-chips-could-pack-data...
- incompatible 2y ago: The research group in Japan sought to create a superconductor microprocessor that’s adiabatic, meaning that, in principle, energy is not gained or lost from the system during the computing process. I thought that there was a law of information theory that requires expending energy, I think it's Landauer's principle. It seems to be disputed though. https://en.wikipedia.org/wiki/Landauer%27s_principle https://en.wikipedia.org/wiki/Landauer%27s_principle
- bryanlarsen 2y agoIf the superconducting microprocessor is 80x as efficient as a normal micro, that means that it uses about 100 million times as much energy as Landauer's principle. (A normal micro uses a billion times as much, and Landauer's energy is ~1/5th at superconducting temperature).
- incompatible 2y agoYes, but the quote suggests no energy transfer at all. All you need then is a cold place (somewhere in remote space perhaps, or after the heat death of the Universe) and your computation can continue forever without power. It doesn't seem intuitive that that would be possible.
- reaperman 2y agoIt is extremely likely that the quote is hyperbolic (wrong / inaccurate). If someone broke Landauers limit, that would be a massive headline in academia. Hell even reasonably approaching Landauer’s limit would be huge news. Most likely this headline is a confusion from how signal/power transmission (rather than calculation/work) is truly lossless in superconductors.
- jakobson14 2y agoContinue forever? no. Be performed once at no cost? maybe. I'm kinda sceptical that a computation to which the 2nd law is indifferent would occur spontaneously without immediately reversing. The 2nd law is what determines the direction that things typically progress.
- boznz 2y agoGreat, I can make my software even more shitty, and nobody will notice.
- 77pt77 2y agoConvenience always wins against quality.
- ForOldHack 2y agoIs there a hard limit on ensh*tification? I was just posting about Yelp, and reddit from a cell phone, and the thought crossed my mind to just close mobile browsing forever.
- lytedev 2y agoPardon my ignorance, but would this then be a semisuperconductor or a supersemiconductor?
- kragen 2y agono, they use jjs
- rapsey 2y agoIs there any company trying to bring this to market?
- campers 2y agoImec working on this approach too https://spectrum.ieee.org/superconducting-computer https://spectrum.ieee.org/superconducting-computer
- BenoitP 2y agoThis is the future. As we try to go 3D and start stacking dies, the limiting factor of heat is getting even more blocking. It's not about consuming less electricity. It's about dissipating less of it as heat inside the microprocessor. The future will made of tiny porous cubes that are tall sandwiches of RAM and CPU/GPU/etc
- sigmoid10 2y agoSuperconductivity with current materials is hard. Allost always because of the cooling. You can't just fabricate a porous cube of transistors and put it in a liquid helium ice bath. You need to have excess heat flowing out in a stable and predictable way. Otherwise once the center reaches critical temperature, the whole thing will explode. There's a reason why everyone is desperately searching for room temp low pressure sc materials. I doubt we'll see industry applications in large scale computing before that.
- mlhpdx 2y agoTotally true, but it’s interesting that this technology lends itself to incremental improvements. And those improvements can be driven both from the hardware side and the software side. It seems like a virtuous cycle driving this to economic viability and optimization is possible. I’m no expert, though, so this is strictly my imagination.
- est31 2y agoAccording to the paper, their demonstration chip MANA has 21k of JJ units, which according to their estimates correspond to around 5k transistors. To compare, a single Nvidia GA100 has 54 * 10^9 transistors.
- timschmidt 2y agoSome versions of the venerable MOS Technologies 6502 have only 3,218 transistors. The Intel 8080 has somewhere between 4,500 and 6,000. 5k transistors is square in the middle of "plenty for a classic 8 bit micro". Enough to run a basic *nix or embedded RTOS.
- actinium226 2y agoThere's something I'm missing, they say the prototype hits 2.5 GHz, how is that possible if they only have the equivalent of 5k transistors? Or is clock cycle independent of transistor count?
- g15jv2dp 2y agoIt depends on what you have your transistors do. You could even have one single transistor that you switch on/off very very quickly. You'd need to find a transistor with sub-ns switching time to reach >1GHz. It's not a very interesting "computation," though.
- johntb86 2y agoAdding more transistors doesn't make your clock got faster, and it doesn't increase the speed of an individual transistor. The reason computers got both more transistors and faster in the past was that the transistors were continually shrinking; for a traditional MOSFET, Dennard scaling means that the smaller the transistor (and therefore the smaller its capacitance and voltage), the faster it switches. This device doesn't use MOSFET technology, so its scaling rules are different.
- mrguyorama 2y agoI'm very confused but I mean this in the utmost sincerity: What made you think transistor count and clock speed were linked? What was your line of thought? How did you think overclocking worked, by dynamically removing transistors from the chip?
- bgnn 2y agoInteresting. To give some context to the current problem: the classical (CMOS) logic gates energy is expended to charge or discharge the load capacitance of each electrical node during a state change. Charging a capacitor to a certain voltage requires E=CV^2 amount of (Joules) energy (C in Farads, V in volts). From this, half of it is the energy stored at the capacitor, other half is the energy converted to heat on the transistors. This is so far the most efficient way we can build large scale integrated logic, and at best it is 50% efficient. In reality there is also unwanted inefficiencies, making it close to 30% or so. Good to keep in mind: 100% of the energy becomes heat because the charged capacitor needs to be discharged at some point to change its state. This is becoming a huge thermal management nightmare.
- dschuetz 2y agoHow much energy was needed for the cryostat? I haven't found anything on that in the article.
- kragen 2y agounfortunately the title says 'superconducting' when it should say 'reversible'
- deleted 2y ago[deleted]
- Hugsun 2y agoI'm surprised that this wasn't done earlier. An experiment like this seemed like an obvious useful thing to try the first time I heard about superconductors, some decades ago. Perhaps it is due to the technical difficulty of the experiment.
- grahamrow 2y agoThe original superconducting logic schemes were established a long time ago and companies started working on computing circuits as early as the 1960s. IBM spun out its own attempt in the early 1980s when it became apparent that this CMOS thing was going to pan out a lot faster.
- quux 2y agoTo quote Norm MacDonald: ... according to a report in the medical journal "DUH"
- lacoolj 2y agoThis will be incredible when the cooling at consumer-level has been figured out. I do wonder what kind of material requirements/availability there will be though. Even things like touchscreens and other rare earth metals are either getting scarce or controlled by one or two countries. Regardless, exciting news here for all of us
- marcosdumay 2y agoLots of people handle liquid nitrogen in all kinds of different field applications. Cooling things is not that hard.
- jonjenk 2y agoRight. But this requires cooling to liquid helium temperatures. That's a separate level of hard and cost compared to liquid nitrogen.
- cashsterling 2y agoI worked on a team (at a Company) that built a Scanning SQUID Microscope (SSM) to image magnetic flux trapping in superconducting circuits. The organization that bought the SSM is working on these kinds superconducting microprocessors. A SSM uses a SQUID (superconducting quantum inference device) as an extremely sensitive magnetic flux sensor; SQUID sensor requires further amplification which is also typically a SQUID-based low-noise amplifier (long story). Same Company (I worked for) built cryostats for quantum computing research and all kinds of other cryogenic needs. There are a lot of issues with designing, fabricating, operating these sort of circuits at large scale... hence the need for a microscope to study flux trapping and other phenomena of operating circuits. But, overall, I'm optimistic that this technology can work. A note about energy consumption of this technology. Niobium thin film superconducting circuits have to be cooled to about 4 Kelvin to be 'properly 'operational'. Heat leaks from higher temperature stages into the 4 Kelvin cooling zone via conduction of thermal insulating supports, electrical signal lines, and thermal blackbody radiation. Several kW of power are required to provide 1 Watt of cooling power at 4 Kelvin. There are also small resistive/impedance losses in electrical signal lines connecting room temperature electronics to the superconducting chip. So... I think calling the microprocessor 'adiabatic' is a little disingenuous. Small amounts of power, in the form of many nano-amp and micro-amp currents are required to operate and interface with the chip... the chip cannot operate without this electrical interface. In additional, in a test environment where researchers are only running one chip... the overall cryogenic system, electronics, and superconducting chip are wildly energy inefficient compared to current microprocessors. But the "forward looking statement" is that hundreds of microprocessors could be run in one cryostat and the 5kW cooling budget would replace the power draw of 100's of classical microprocessors while also provide higher equivalent FLOPS per process processor. But this "forward looking statement" is NOT true today, as far as I am aware.
- written-beyond 2y agoI appreciate your comment it's probably very informative to a lot of people here on HN. I will admit this comment for me, read like something out of r/vxjunkies. Props to you and your team for building amazing stuff. Squid and Niobium are very entertaining names.
- darknoon 2y agoRelevant video about some of the history of superconducting computers: https://www.youtube.com/watch?v=14r2oMsAaE8 https://www.youtube.com/watch?v=14r2oMsAaE8
- Animats 2y ago4 bit CPU, about 10,000 gates, 5 GHz. So just a proof of concept at this point. Cyrogenic computing has been too far outside the mainstream. The mainstream technology improved faster than the cyrogenic stuff. NSA put large amounts of money into cyrogenic computing, from the 1960s on. "I want a thousand-megacycle computer. I'll get you the money!" - an NSA director. It never really worked out, although at one point some special purpose device, probably a key tester, was actually built. The first round of that cyrogenic technology used cyrotrons. Cyrotrons were fast, but, being magnetic devices, not small enough. The second round used Josephson junctions. NSA finally gave up on that around the time ordinary CMOS passed 1GHz. Lately there's been some interest again.[1] [1] https://spectrum.ieee.org/will-the-nsa-finally-build-its-superconducting-spy-computer https://spectrum.ieee.org/will-the-nsa-finally-build-its-sup...
- tcgv 2y agoThat's the way technology evolves, some bets pay off, while others don't.
- vlovich123 2y agoActually, it evolves in a random walk. Old ideas can become more practical because while we abandoned an approach, we got better at things that would make it more feasible another time around (eg VR today looks nothing like the VR of my childhood due to advances across the board in computing power, computer language expressivity, game dev tools, IMUs, IMU algorithms development, etc etc etc). That’s a case of a path opening up due to investment over time that couldn’t be accomplished by a bet. Other times bets are insufficient in size - a bet that requires 100B to unlock trillions may seem like a failure at 10B, especially if you didn’t properly estimate the size of a market (or the market isn’t large enough for that yet).