How close is a quantum computer?

Australian Institute of Physics, Australian Institute of Physics Congress, Media releases

Quantum computers promise ultra-powerful, high speed number crunching. They’ll help us to search vast databases and model biological molecules at an atomic level.

They will crack the encryptions we rely on for banking and online security but also help us make new, unbreakable codes.

Today UNSW’s Andrew Dzurak talks about progress and his team’s creation in September of a quantum bit – writing and reading the quantum state of a single electron in a silicon system – like in conventional computers.

Two ANU research teams will report on:

  • their discovery of a way of making quantum devices more stable
  • and switching eight beams of entangled light in a laser – for high speed networks.

A Macquarie Uni team reports on a new room temperature source of single photons

And Ben Eggleton from Sydney reveals progress towards a light-powered communications chip

All at the national physics and optics congress in Sydney today.

Fighting fire with fire

Until now quantum computing systems have been very fragile and easily disrupted. Dr Andre Carvalho from ANU and Mr Martin Ringbauer from the University of Vienna will talk about ways in which researchers are fighting back and stabilising quantum systems.

They have shown that adding more energy to the system using laser light actually allows it to maintain its integrity, provided the system is measured in the right way. They’ve also found that entanglement may be unnecessary, even counterproductive.

Branching out

Mr Seiji Armstrong and his colleagues at ANU were profiled on ABC-TV’s New Inventors when they showed they could squeeze multiple entangled beams of light or modes into one laser, allowing for faster and more efficient transfer of information. They can now use one detector in real time to switch between up to eight of these modes in a single laser beam. It’s all part of developing the next-generation super-fast networks needed to drive the quantum computing of the future.

Materialising quantum sensors

Silicon carbide (SiC) looks like becoming a material of choice for quantum sensors, says Dr Stefania Castelletto of Macquarie University. Within its multilayered structure, the spin states of electrons can be altered and controlled by microwaves – and the changes in electron spin are linked to the emission of photons or packets of light. Her research group has been the first to use the material as a stable, room temperature source of single photons. The work paves the way to merge together several areas of quantum research and should allow the engineering of fully integrated quantum devices, she says.

Light-powered communication

A new chip, which uses light instead of electronic signals to process information, could lead to high security, energy-efficient internet links more than 1,000 times faster than today’s networks.

This “photonic chip” uses special glass, photonic crystals, to bend light and slow it down. The slower the light travels, the more efficiently the chip can operate—and the smaller and more energy efficient the resulting devices can be.

Developed by Prof Ben Eggleton and his team at the Australian Research Council Centre for Ultrahigh bandwidth Devices for Optical Systems (CUDOS) at the University of Sydney, the same technology could be used to build quantum computers and secure communications networks.