6 ms·

Until there is an undisputed demonstration of quantum supremacy [1], which at last check there isn't, then no, these (or any other quantum computer) is not fast

Until there is an undisputed demonstration of quantum supremacy [1], which at last check there isn't, then no, these (or any other quantum computer) is not faster than classical approaches. The reasons companies are investing in these is R&D, or in more capitalist terms, FOMO: if quantum computing does turn out to offer an edge someday, you want to be able to make use of it fast, instead of scrambling to catch up. [1] https://en.wikipedia.org/wiki/Quantum_supremacy https://en.wikipedia.org/wiki/Quantum_supremacy

trevyn 6y ago
Quantum can be still be faster/more powerful per dollar than classical without achieving supremacy, right? There are a lot of big problems that are tractable on classical, but if they become orders of magnitude cheaper on quantum, that's still a great win.
- reikonomusha 6y ago
  Usually this is termed “quantum advantage”, when it’s better than classical at some commercial metric that “matters”.
tsimionescu 6y ago
As far as I know, quantum supremacy has been unequivocally demonstrated, albeit not on a very interesting problem, and of course without solving the quantum error correction problem: https://www.scottaaronson.com/blog/?p=4372 https://www.scottaaronson.com/blog/?p=4372
- hannob 6y ago
  And noteworthy in regards to this thread: Not with a D-Wave computer.
- howlgarnish 6y ago
  As that article notes, IBM (which obviously has a dog in this fight) has strongly disputed Google's claims. I don't have enough expertise to judge.
  - himinlomax 6y ago
    Iirc IBM came up with an optimization of the classical algorithm (specifically using enormous but still (barely) practical amounts of RAM) that reduced the advantage of Google's quantum algorithm by an order of magnitude or two. There was two issues with their argument though. First, they hadn't implemented it yet, which is rather ironic considering that Google's feat was in actually delivering an implementation. Second, Google's quantum computer is still orders of magnitude faster than IBM's optimized classical approach, not to mention cheaper.
  - tsimionescu 6y ago
    Neither do I, but Scott Aaronson surely does, and he believes Google have unequivocally proved quantum supremacy. According to him, IBM has disputed the extent of the advantage proven by Google, but not the actual fact that they succeeded.

trevyn 6y ago

Quantum can be still be faster/more powerful per dollar than classical without achieving supremacy, right? There are a lot of big problems that are tractable on classical, but if they become orders of magnitude cheaper on quantum, that's still a great win.

reikonomusha 6y ago
Usually this is termed “quantum advantage”, when it’s better than classical at some commercial metric that “matters”.

tsimionescu 6y ago

As far as I know, quantum supremacy has been unequivocally demonstrated, albeit not on a very interesting problem, and of course without solving the quantum error correction problem: https://www.scottaaronson.com/blog/?p=4372 https://www.scottaaronson.com/blog/?p=4372

hannob 6y ago
And noteworthy in regards to this thread: Not with a D-Wave computer.
howlgarnish 6y ago
As that article notes, IBM (which obviously has a dog in this fight) has strongly disputed Google's claims. I don't have enough expertise to judge.
- himinlomax 6y ago
  Iirc IBM came up with an optimization of the classical algorithm (specifically using enormous but still (barely) practical amounts of RAM) that reduced the advantage of Google's quantum algorithm by an order of magnitude or two. There was two issues with their argument though. First, they hadn't implemented it yet, which is rather ironic considering that Google's feat was in actually delivering an implementation. Second, Google's quantum computer is still orders of magnitude faster than IBM's optimized classical approach, not to mention cheaper.
- tsimionescu 6y ago
  Neither do I, but Scott Aaronson surely does, and he believes Google have unequivocally proved quantum supremacy. According to him, IBM has disputed the extent of the advantage proven by Google, but not the actual fact that they succeeded.