In a partnership with Google, researchers from the University of California, Santa Barbara, are working towards setting up a quantum computing research laboratory. Professor John Martinis from the University of California, who joined the team at Google a year ago, is directing work on superconducting aluminium chips that function very near the absolute zero temperature (0°K, which is −273.15° C or −459.67° F). This research, which had already begun before Professor Martinis joined Google, has yielded results that were published today in “Nature”.
Google started investing interest in quantum computing in 2009. It worked together with D-Wave Systems, who sell a proto-form of a quantum computer. Microsoft has a quantum computing research program as well. But with all the energy devoted, it will still take some time before all the difficulties of this new technology are solved and these computers become accessible to the public.
Quantum programming is based on qubits, the quantum equivalent of bits. They are quantum-mechanical systems with two simultaneous states (for instance, the polarization of one photon, that can be vertical or horizontal), which make possible the codification of more information. Because of the superposition of states in qubits, they can code both 1 and 0 at the same time, thus reducing the difficulty of large calculations. A quantum computer requires the assembling of many qubits together, which makes it susceptible to errors because these qubits code the 1s and 0s using minute quantum mechanical effects that cannot be detected at normal temperatures, nor in large scales. Thus heat and other disturbances can distort the quantum states and cause failures.
Most of the research in this field is set on trying to make the systems of qubits correct its internal errors. Martinis’s team of scientists has advanced a very plausible technique for achieving this goal, known to experts as “surface codes”. A nine-qubit chip was programmed to monitor its own errors (called “bit flips”) – each qubit monitored the others and took action to ensure that the mistakes would not affect later steps of the calculation, but the qubit network was not able to actually correct the bit flips. Of course, a lot more is to be done before the errors become harmless to the system, according to researcher Daniel Gottesman. Simple bit-flips like the ones the Martinis group is working on require classical algorithms, but there are other errors (like phase alterations due to environmental noise) whose fixing presupposes other, more complicated algorithms. Google quantum electronics engineer Austin Fowler declared that the group of researchers is now working on error-checking in systems larger than nine qubits. Gottesman (who works on quantum error correction in Waterloo, Ontario) is confident that it will not take more than a few years before error correction techniques are perfected.
image source: fossBytes
Matthew Slotkin
