One question: You describe a quantum computer as “hypothetically more powerful than total calculation power of the universe”. What does that mean?
On the one hand, even a deterministic Turing machine is hypothetically more powerful than the total calculation power of the universe, since a hypothetical Turing machine has an infinite tape. So your statement would appear to be trivially true (because you said “hypothetical”).
On the other hand, it seems that no actual quantum computer can be more powerful than the total calculation power of the universe, since any actual quantum computer that we were to build would be part of the universe.
So, what does this statement really say regarding the power of a quantum computer?
My statement mostly repeat the claim which I read somewhere that computational power of QC of several thousand qubits will be stronger then computational power of classical computer in the size of all Universe.
I can’t find the link now, but maybe will find it later.
I read somewhere that computational power of QC of several thousand qubits will be stronger then computational power of classical computer in the size of all Universe.
I have read this sort of claim as well. However, I recommend skepticism; there has been a lot of hyperbole in the popular press regarding the potential power of quantum computing. A good source of objective information about the potential and limitations of quantum computing is Scott Aaronson’s blog, Shtetl-Optimized. Scott was a professor at MIT and is now at the University of Texas at Austin—he is very knowledgeable about QC and, equally important, he is an engaging writer that can make complex topics (reasonably) clear to non-specialists. He has spent a bit of time on his blog debunking some of the wilder claims regarding the power of QC.
Interesting list, thanks for posting it.
One question: You describe a quantum computer as “hypothetically more powerful than total calculation power of the universe”. What does that mean?
On the one hand, even a deterministic Turing machine is hypothetically more powerful than the total calculation power of the universe, since a hypothetical Turing machine has an infinite tape. So your statement would appear to be trivially true (because you said “hypothetical”).
On the other hand, it seems that no actual quantum computer can be more powerful than the total calculation power of the universe, since any actual quantum computer that we were to build would be part of the universe.
So, what does this statement really say regarding the power of a quantum computer?
My statement mostly repeat the claim which I read somewhere that computational power of QC of several thousand qubits will be stronger then computational power of classical computer in the size of all Universe.
I can’t find the link now, but maybe will find it later.
I have read this sort of claim as well. However, I recommend skepticism; there has been a lot of hyperbole in the popular press regarding the potential power of quantum computing. A good source of objective information about the potential and limitations of quantum computing is Scott Aaronson’s blog, Shtetl-Optimized. Scott was a professor at MIT and is now at the University of Texas at Austin—he is very knowledgeable about QC and, equally important, he is an engaging writer that can make complex topics (reasonably) clear to non-specialists. He has spent a bit of time on his blog debunking some of the wilder claims regarding the power of QC.