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Google's "quantum supremacy" paper was about a 53 qubit chip in 2019 [1]. This year, they reported having 70 qubits [2]. Looking at the papers (and supplements)
by fsh 3y ago
Google's "quantum supremacy" paper was about a 53 qubit chip in 2019 [1]. This year, they reported having 70 qubits [2]. Looking at the papers (and supplements), the gate fidelities and qubit lifetimes have stayed roughly the same. This really doesn't look like anything like Moore's law to me.
[1] https://doi.org/10.1038/s41586-019-1666-5 https://doi.org/10.1038/s41586-019-1666-5
[2] https://doi.org/10.48550/arXiv.2304.11119 https://doi.org/10.48550/arXiv.2304.11119
- orlp 3y agoIf we didn't invent photolithography, we'd still be using computers the size of buildings limited to universities and military installations. Right now no one knows how to build a scalable quantum computer. But as soon as we find out the equivalent of lithography for building quantum chips, the progress will come, and it will come quickly and suddenly.
- Mistletoe 3y agoHow do you know there is an equivalent process for quantum chips?
- krastanov 3y agoThere are some equivalents already in existence (spin qubits in CMOS processes), that use the exact same lithography techniques. There are a few other potential alternatives too. All of them suffer from harder engineering challenges than the much "easier" to produce (in small volumes) transmons and trapped ions/atoms/molecules. Thus a plausible future is one in which the first somewhat-useful quantum computers are tens of thousands of qubits in transmon/ion hybrid systems. Then (in that plausible future) the spin qubits in CMOS do catch up, and thanks to their superior manufacturing scalability, they blow past the capabilities of transmons/ions. Not too different from how we had to use vacuum lamps while we figure out how solid state systems can work... Or spinning hard drives before we figured out SDDs. Or maybe none of this would work out and the whole field would be a bust... but you know Clarke's laws https://en.wikipedia.org/wiki/Clarke%27s_three_laws https://en.wikipedia.org/wiki/Clarke%27s_three_laws
- orlp 3y agoI don't. All I'm saying is that progress can be linear/non-existing until a breakthrough is made that allows scaling. For microchips this was lithography. After such a breakthrough the scaling can (temporarily) be exponential.
- marcosdumay 3y agoLast time I took around 1 hour to do a review of literature, I discovered that the size of those computers were growing at a linear rate of around 4 qbits/year. It got slightly faster on the last few years, I don't know if inherently so or just due to random fluctuation. Yet people keep repeating that claim that the growth is exponential, based on no evidence at all.
- krastanov 3y agoFor example, is this developer roadmap far from the truth? https://newsroom.ibm.com/2022-11-09-IBM-Unveils-400-Qubit-Plus-Quantum-Processor-and-Next-Generation-IBM-Quantum-System-Two https://newsroom.ibm.com/2022-11-09-IBM-Unveils-400-Qubit-Pl... While it is too early to call it exponential, it is wildly faster than 4 qubits/year. Same can be said about other hardware systems too (trapped ions, neutral atoms, and with some caveats photonics and color centers too).
- marcosdumay 3y agoThis is the kind of article I threw away for being unsubstantiated. Besides, it has 2 "real" datapoints, and both are completely different from the sizes everybody else were achieving in well-public and well-reviewed computers. If you restrict your data to devices other people were allowed to touch, a lot of those huge numbers just disappear.
- EvgeniyZh 3y agoPeople in academia are having access to 127-qubit computer, not sure about 400+ option. It more like you don't have much to do with this amount of qubits that noisy (they aren't particularly bad, just not good enough) and with sparse connectivity.
- squokko 3y agoI would not believe anything I heard from IBM unless I also heard it from someone else