Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Superconducting Microprocessors? Turns Out They're Ultra-Efficient (2021)

spectrum.ieee.org

Post reply on HN
Print view View original

61–70 of 100 posts

Re: Superconducting Microprocessors? Turns Out They're Ultra-Efficient (2021)

#61

Post by stracer »

AnthonyMouse wrote: post #34
philipswood wrote: post #25

Earlier quoted context omitted.

Energy is expended when you zero or set a bit. If you compute reversibly you need use special logic gates to not throw any bits away during the computation, like the Toffoli gate. All your operations need to have the same number of input and output bits and needs to be able to run forwards and backwards. Effectively you set or zero no bits during the entire computation that can't be losslessly reversed. If you struct…

Wait, so does this imply (ignoring the time requirements) that you could do NP calculations with a feasible amount of energy , because the inputs and outputs are small? Combine that with something that uses time dilation to make it go fast (from our frame of reference) and you'd be giving even hypothetical quantum computers a silver medal.

> time dilation to make it go fast (from our frame of reference)

The only way to do that is that we move to a place from which the computer processes appear accelerated, e.g. into a strong gravity well. That isn't very useful, because we do not have such a well nearby, as only very dense hypothetical objects can provide it (e.g. black holes), and it would not be compatible with life to move there.

Re: Superconducting Microprocessors? Turns Out They're Ultra-Efficient (2021)

#62

Post by lacoolj »

This 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

Re: Superconducting Microprocessors? Turns Out They're Ultra-Efficient (2021)

#63

Post by tarikjn »

wizardforhire wrote: post #2

Another 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.

I’ve been thinking about making cheaper cryocoolers for CO2 condensation. I’d love to hear your perspective on other applications :)

Re: Superconducting Microprocessors? Turns Out They're Ultra-Efficient (2021)

#64

Post by cashsterling »

I 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.

Re: Superconducting Microprocessors? Turns Out They're Ultra-Efficient (2021)

#65

Post by wizzwizz4 »

philipswood wrote: post #53
AnthonyMouse wrote: post #34

Earlier quoted context omitted.

Wait, so does this imply (ignoring the time requirements) that you could do NP calculations with a feasible amount of energy , because the inputs and outputs are small? Combine that with something that uses time dilation to make it go fast (from our frame of reference) and you'd be giving even hypothetical quantum computers a silver medal.

I think a longer runtime for a terminating program will require more state to be kept. Every step needs to keep extra reversibility information. So I don't think this gives any edge on NP. I suspect that even if you waited for the universe to cool down a lot by waiting aeons and then performed computations arbitrarily slowly you'd still be limited by your starting energy (maximum bits you can write to start with). Al…

The amount of energy it takes to write a bit depends on the temperature. But you'd still be limited by the amount of substrate available.

Re: Superconducting Microprocessors? Turns Out They're Ultra-Efficient (2021)

#67

Post by written-beyond »

cashsterling wrote: post #64

I 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 SQUI…

I 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.

Re: Superconducting Microprocessors? Turns Out They're Ultra-Efficient (2021)

#68

Post by mrguyorama »

actinium226 wrote: post #54
timschmidt wrote: post #42

Earlier quoted context omitted.

Some 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.

There'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?

I'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?

Re: Superconducting Microprocessors? Turns Out They're Ultra-Efficient (2021)

#69

Post by marcosdumay »

lacoolj wrote: post #62

This 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

Lots of people handle liquid nitrogen in all kinds of different field applications. Cooling things is not that hard.

Re: Superconducting Microprocessors? Turns Out They're Ultra-Efficient (2021)

#70

Post by marcosdumay »

tuatoru wrote: post #21
hn72774 wrote: post #11

Earlier quoted context omitted.

Are you referring to the hardware cost vs operating cost? Or how the units are financed?

capex = 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.

> it doesn't matter how they are financed

If you have spherical banks in a vacuum, you can simply follow "capital_opex = capex * interest_rate" and then "profit = revenue - total_opex".

But things tend to not work that way on practice.

Post reply on HN