Google was in poll position to win the race for quantum supremacy, the point at which a quantum computer can do things a conventional one can’t. But IBM seems to have pulled the rug from beneath their rivals by carrying out the largest simulation of a quantum computer to date.
It had long been assumed that simulating more than 49 qubits—the quantum computing equivalent of the digital bits used in standard computers—was near enough impossible due to the colossal amount of memory it would require. But by using some smart mathematical shortcuts the group was able to simulate a 56-qubit machine using just 4.5 terabytes of memory rather than the exabyte (one million terabytes) previous approaches would have required.
That means the 49-qubit processor Google plans to unveil before the end of this year will not take the quantum supremacy crown, and it might take longer than some have predicted for quantum computers to surpass their conventional cousins. IBM researchers say they still don’t know the limits of how many qubits their approach could simulate.
They are at pains to say their findings in no way undercut the quest for practical quantum computers, which is unsurprising seeing as IBM is also one of the leading players in the race. The company has already built a 17-qubit processor and says it plans to achieve 50 “in the next few years.”
Read More Here: singularityhub.com/2017/11/08/ibm-just-simulated-the-biggest-quantum-computer-to-date-what-that-means-for-the-field/