The Speculist

Closer to Quantum Computing

A team working in Japan has developed one of two components essential for the development of a quantum computer:

The team has built a controlled NOT (CNOT) gate, a fundamental building block for quantum computing in the same way that a NAND gate is for classical computing.

By manipulating particles that exist in more than one state at a time, quantum computers will operate at speeds far greater than any existing computing technology. Here's why:

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.

The same team which has now developed the CNOT also developed the first qubit back in 1999. So they have both pieces of the puzzle now. It's just a matter of time before quantum computing becomes reality. Their estimate is 10 years.

via KurzweilAI.net