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Japan team reports quantum computing breakthrough
Research team demonstrates one of the two building blocks needed for a quantum computer

A research team in Japan says it has successfully demonstrated for the first time in the world in a solid-state device one of the two basic building blocks that will be needed to construct a viable quantum computer. ...

...Among the startling properties of qubits is that they do not just hold either binary 1 or binary 0, but can hold a superposition of the two states simultaneously. As the number of qubits grows, so does the number of distinct states which can be represented by entangled qubits. Two qubits can hold four distinct states which can be processed simultaneously, three qubits can hold eight states, and so on in an exponential progression.

So a system with just 10 qubits could carry out 1,024 operations simultaneously as though it were a massively parallel processing system. A 40-qubit system could carry out one trillion simultaneous operations. A 100-qubit system could carry out one trillion trillion simultaneous operations.

That means calculations, such as working out the factors of prime numbers, which present problems for even the fastest supercomputers could be trivialized by a quantum computer. As an example Tsai estimated that using the Shor Algorithm to factor a 256-bit binary number, a task that would take 10 million years using something like IBM Corp.'s Blue Gene supercomputer, could be accomplished by a quantum computer in about 10 seconds. ...