Scientists have long dreamed of developing quantum computers, machines that rely on arcane laws of physics to perform tasks far beyond the capability of today’s strongest supercomputers. ...This is not going to happen. Check back on this blog at the end of the year to see if I am wrong.
But to realize those visions, scientists first have to figure out how to actually build a quantum computer that can perform more than the simplest operations. They are now getting closer than ever, with IBM in May announcing its most complex quantum system so far and Google saying it is on track this year to unveil a processor with so-called “quantum supremacy” — capabilities no conventional computer can match. ...
Alan Ho, an engineer in Google’s Quantum Artificial Intelligence Lab, told the conference his company expects to achieve quantum supremacy with a 49-qubit chip by the end of this year.
There has been 25 years of research on quantum computer, and no one has achieved quantum supremacy. Now we have Google, IBM, and others making specific predictions. We will finally see whether they are right or wrong.
Some of those factors can work against one another; adding more qubits, for instance, can increase the rate of errors as information passes down the line from one qubit to another. ...Yes, there could be technological roadblocks to doing what they want. These problems have not been solved, and may never be solved.
And increasing the number of qubits, no matter what technology they are used with, makes it harder to connect and manipulate them—because that must be done while keeping them isolated from the rest of the world so they will maintain their quantum states. The more atoms or electrons are grouped together in large numbers, the more the rules of classical physics take over—and the less significant the quantum properties of the individual atoms become to how the whole system behaves. “When you make a quantum system big, it becomes less quantum,” Monroe says.
Chow thinks quantum computers will become powerful enough to do at least something beyond the capability of classical computers — possibly a simulation in quantum chemistry — within about five years. Monroe says it is reasonable to expect systems containing a few thousand qubits in a decade or so. To some extent, Monroe says, researchers will not know what they will be able to do with such systems until they figure out how to build them.This is more delusional thinking. A lot of smart ppl have done a lot of good theoretical work on what quantum computer algorithms would be feasible, with a decent number of qubits. The main application will be to destroy the security of internet communications. This impact will be overwhelmingly negative, if quantum computers are feasible.
Preskill, who is 64, says he thinks he will live long enough to see quantum computers have an impact on society in the way the internet and smartphones have — although he cannot predict exactly what that impact will be.
There are some other possibilities, like simulating chemical reactions. These might have some research interests. It is extremely that these would have commercial utility. It is even more doubtful that there would be any consumer applications.