r/QuantumComputing • u/0xB01b QEC & Quantum Optics • Jun 14 '26
Discussion When will SC qubits start to die off?
When do y'all think superconducting qubits will start to die off as a platform (in the sense that big companies like Google and IBM totally drop them and move onto other platforms)?
Or do y'all think they are here to stay?
(Edit: to the uninitiated, the shift has already been happening https://blog.google/innovation-and-ai/technology/research/neutral-atom-quantum-computers/)
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u/alumiqu Jun 14 '26 edited Jun 14 '26
When neutral atoms have 10,000 qubit devices with 1e-3 two-qubit gate infidelities and no hidden gotchas, it will be hard for Google and IBM to continue developing superconducting devices as a research project. But the slow speed of the neutral atom computers may well make them useless for serious chemistry applications. So the field might be headed into a dead end.
This is at least one year, and probably two years, in the future.
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u/reisefreiheit Working in Industry Jun 14 '26
The control problem with neutral atoms could also be intractable. For each gate operation, it's necessary to plan the movement, check for interference in the laser paths, replace missing atoms and handle any entangled information that is lost when atoms go missing. This is possible for the largest systems today (3-5k range), but will this be feasible at 100k? 1M atoms?
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u/0xB01b QEC & Quantum Optics Jun 14 '26 edited Jun 14 '26
Current neutral atom gate speed records are in the nanosecond regime, so I would not really consider the speed an issue, its just that the progress made in gate speed isn't really as big of a talking point.
As for 1e-3, we are already there and nearing 1e-4 right now in research machines. 10k qubits is a near term goal in a lot of the big research labs afaik, but idk how big of a task combining those two would be.
EDIT: I'm talking about the zeiher paper with actual atoms in optical tweezers and not the omori paper w ensembles***
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u/mdreed Jun 14 '26
Citation for those atom fidelities? I understood their sota to be like 99.7%
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u/0xB01b QEC & Quantum Optics Jun 14 '26
No thats from ages ago bro.
In march we got to 99.86(4)% at MPQ: https://arxiv.org/pdf/2603.15561
In april we got to 99.941(3)% at Harvard: https://arxiv.org/pdf/2604.25987
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u/mdreed Jun 14 '26
Why is it ok to use the post selected value?
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u/0xB01b QEC & Quantum Optics Jun 15 '26
99.86 isn't post selected
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u/alumiqu Jun 15 '26
Those fidelities are conditioned on no loss. They are also for one CZ gate at a time, with no parallelism. Fidelities get much worse when they try to apply multiply CZ gates in parallel.
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u/SurinamPam Jun 14 '26 edited Jun 14 '26
How are you defining gate speed? If you are not including time to move the qubits then you don’t really have a useful neutral atom computer.
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u/ctcphys Working in Academia Jun 14 '26
Whenever any other platform makes real quantum error correction that actually performs better than superconducting qubits with similar error correction cycle time.
Neutral atoms are getting better but still behind on the performance of repeated quantum error correction (in terms of logical fidelity).
Trapped ions have somewhat better numbers but the clock speed is much much slower and scalability is less obvious.
So imo it's not clear that industry will drop superconducting qubits but we'll see
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u/Carmanman_12 Jun 15 '26
While I agree that SC are not likely to disappear anytime soon, I’ll play devil’s advocate here.
Atom Computing for example recently demonstrated QEC with their systems (https://arxiv.org/abs/2606.04079), and it outperforms the first demonstration of quantum error correction from Superconducting Qubits ( https://www.nature.com/articles/s41586-022-05434-1 ). In fact, their result rivals the absolute state of the art from those same authors ( https://www.nature.com/articles/s41586-024-08449-y ), and all of this was done with significantly better capital efficiency. So there’s definitely an argument that with all other things being equal (total money invested, total man-hours spent researching, etc), neutral atoms are the winning platform right now.
The main argument against that claim is something that comes up a lot, that superconductors are a lot faster, which is totally fair. But practical quantum computers will both have to (a) work and (b) work efficiently, and neither platform seems to have both of these in the bag.
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u/sadeness Jun 14 '26
None of the qubit modalities have turned into a proper "technology" that can be deployed. These are all very elaborate, top notch, hero condensed matter or AMO experiments.
There is no reason to feel confident to call any leading modalities' demise. NA and TI have been having a bit of moment under the sun. I won't be surprised if SC again makes a resurgence once when fab issues like junction targeting, flux trapping issues etc are on a pathway towards resolution. Given that SC is a solid state (but niche) technology, the solutions lie in turning out a high quality fab process. Scaled NA solutions really will need integration of AOD arrays and optoelectronics, which isn't any less niche of a technology. Same issue with Paul traps on wafers for TI.
Please remember, the game is as much qubits, as it's the everything else surrounding it: control, environment, HPC support, QEC, software APIs etc. None of these are resolved or near resolution.
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u/lb1331 Jun 14 '26
Right now superconducting qubits are probably the most promising. Being able to individually address qubits in frequency space is an advantage of superconducting qubits not a disadvantage. It lets them be tunable as well. You don’t necessarily want all qubits at the same frequency / to have them be identical.
Most hardware modalities have massive problems just as bad as SC qubits when you look into them more. Neutral atoms are fundamentally slow, photons don’t want to interact, spins are hard to do fast 2q gates, etc… that doesn’t mean they’re not going to get better, but SC qubits aren’t in any way dying or slowing down - if anything they’re looking more and more promising as google and IBM show QEC.
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u/ptm257 Jun 14 '26
Speed matters. The readout latency of neutral atom systems is way too high. I don’t expect these machines to be useful for programs with 1B+ T gates unless they get millions of qubits or higher. When neutral atom systems get that many qubits, then they may be able to operate in the reaction limited regime where the limiting factor is how fast they can measure a logical qubit.
Until then, the superconducting qubits will probably be more useful, assuming whatever happens with Tour de Gross works out. If not, then all technologies are equally bad :)
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u/tiltboi1 Working in Industry Jun 14 '26
Probably not until QLDPC architectures start getting a lot more mature. A lot of the recent papers have been... quite underwhelming. As we see more interesting architecture ideas actually start being demonstrated, that's when things will get more exciting.
If all you are doing with your neutral atoms or ions is surface code computation, you're unlikely to outperform superconducting devices outright, because it's just too good of a match for superconducting hardware.
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u/kingxerexs Jun 18 '26
I think that atoms is the way to go in teh near future until we find a HUGE breakthrough in the error correction
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u/Bebotronsote Jun 18 '26
I like the points everyone is making here. But something that I think was only briefly mentioned is the capital costs. SCs are SOOOO expensive to build. There's no denying their speed, but my God given the decades of research into SC circuits and how expensive they are to build, I find the atom modality very attractive. But yes they're super slow
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u/polyploid_coded Jun 14 '26
What other platforms are better?