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Researchers bring quantum computers closer to reality

Quantum computers are set to revolutionise the world of computing, as a research team from Griffith University has discovered with their success in simplifying complex quantum calculations.

Geoff Pryde, physicist and professor at Griffith University, leads the Quantum Optics and Information Laboratory, a research group uncovering and understanding properties of quantum particles such as photons (particles of light). Such studies are inspiring a new wave of technologies to meet the demand for faster computers to solve harder problems, which is where quantum computing is making its mark.

Quantum computers promise unparalleled processing capabilities that can allow certain calculations, ones that would take a regular computer years to solve, to be performed in seconds. A quantum computer can achieve this by using strange but powerful properties of quantum particles to carry out the computation. Just as digital computers store information as bits that are usually represented in the form of 1s and 0s, quantum computers employ quantum bits (qubits) that have the added ability of being in states 1 and 0 simultaneously. Logic gates are used to change the value of the qubits, but building these elements into a fully working quantum computer still remains one of the greatest challenges of modern science.

The difficulty lies in chaining together many small quantum logic gates to build a circuit capable of performing calculations. Unlike bits, qubits are very fragile and are sensitive to the environment that they are in. With this sensitivity comes noise that can accumulate with sequential gate operations, destroying the quantum properties, leading to errors in the calculation. As such, current implementation of quantum computers has been limited to small and medium scale circuits.
Recently Geoff and his research group, along with collaborator Professor Tim Ralph from the University of Queensland, reported in the journal Science Advances on their experimental demonstration of a complex quantum circuit, the quantum Fredkin gate. Named after computer scientist and physicist Edward Fredkin, the gate swaps two qubits depending on the value of the third. Normally this would require a circuit of five smaller gates, but their technique allows the circuit to be implemented directly. This method has the potential to simplify other complex operations and eventually build larger quantum circuits for use in future quantum computing technologies.

While quantum computing is a rapidly developing field with growing interest from universities and tech companies globally, it remains in its infancy. A fully-working, generalised quantum computer still seems a goal set for the future.
Geoff and his team expect that their work to date could be best utilised in short-term quantum technologies such as quantum communication and cryptography, and in specialised applications of quantum simulations of complex physical systems.

Further information

Creative Commons Attribution-NoDerivs 3.0 Australia (CC BY-ND 3.0)
Last updated
18 July, 2017

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