For cracking 1024 bit RSA, I believe we need on the order of 10,000 qubits.
So we are 1% of the way there!
So we are 1% of the way there!
I think this chip would intersect with the exponential.
So...300 qbits by 2031.
I really wish there would be a better parameter which would also inform when they become useful for breaking crypto.
* the number of qbits that can be used to construct a circuit is not always the same as the number of qbits on the processors
* the number of iterations that a circuit can be run for is often obscured
* the amount of time and effort required to construct a circuit is often obscure
* error rates - as you mention
Simple formulas for these things is not a good measure - if an algorithm needs 10000 iterations to work then increasing the number of qbits by 100x when the max iterations is 100 will not get you a working machine.
The real problem is that this is all live science being done as commercial development. None of these machines are close to being useful (as in 20 years away). The science is brilliant though, the capabilities created by the skill that is being developed in creating these devices is going to be very useful in the future. It's just that the money is going into it under false pretenses. For China and the USA this is actually a good thing - it's driving the basic science and that needs to happen somehow. There will be dividends in the future for all of us. For places like Canada, France, Japan and the UK its bad though. These economies need to reap benefits in the next decade from their current investments. In this sense QC money is just poured out onto the ground.
That's been my observation regarding quantum computing since I was first exposed to it around a decade ago. That these are really cool science experiments (in a very literal sense) that are being billed as early stage product development by the companies involved. It's giving the public the impression that quantum computing is at the stage of Woz wiring together the first Apple I in his garage when in fact we're at the stage of research done by Geissler and Crooke in the 1850s that would lead to the development of the first vacuum tube 50 years later.
Disclaimer: I work on the quantum team at Microsoft.