Calculating machines that run on quantum bits (known as qubits, for short) are, by some accounts, the future of computation. Quantum computers have the theoretical advantage that they can solve with ease certain mathematical problems, such as the factorisation of large numbers, which are hard or impossible for classical machines. This is possible thanks to a qubit’s ability to remain, through the peculiarities of quantum mechanics, in many quantum states simultaneously. The more qubits a computer has, the more mind-bogglingly gigantic are the calculations it can handle. Finance, medicine,chemistry and artificial intelligence are thus all expected to be transformed by quantum computing.
preparing such a device, which will have 49 qubits. It is rumoured that this will be ready for demonstration before the year is out. Though not confirming such rumours,John Martinis, Google’s quantum-computing boss, told the AAAS meeting about some of the problems involved in doing so.
than engineers, they typically cite their best measurements when reporting qubit error rates, in order to show the machine’s capability. That number is of little interest to Dr Martinis and his team, though. They are thinking like engineers, attempting to build a robust, working device. In this case,Dr Martinis says, it is the worst error, not the slightest, that is important.
Project Bristlecone’s main concern is the quality of the qubits. The theoretical ability to beat a classical computer is of little use if the hardware that serves as the physical representations of those calculations is misfiring or dodgy.
Everything must be and remain perfect.
computing is now in the equivalent of the days of vacuum tubes running calculations in room-sized computers. And that was a world in which the tubes of ten blew,and bugs in the system were literal ones,namely insects that caused short circuits.Such behemoths were able to turn into today’s sleek machines because, at every stage of the journey, they were useful. And that, ultimately, is the standard quantum computers will have to match.