Towards quantum Internet with combined optical and electrical technique

May 01, 2013
Professor Sven Rogge and Dr. Chunming Yin, University of New South Wales, are shown in the ARC Centre of Excellence for Quantum Computation and Communication Technology. Credit: UNSW

An Australian team led by researchers at the University of New South Wales has achieved a breakthrough in quantum science that brings the prospect of a network of ultra-powerful quantum computers - connected via a quantum internet –closer to reality.

The team is the first in the world to have detected the spin, or quantum state, of a single atom using a combined optical and electrical approach.

The study is a collaboration between researchers from the ARC Centre of Excellence for Quantum Computation and Communication Technology based at UNSW, the Australian National University and the University of Melbourne. It is published in the journal Nature.

UNSW's Professor Sven Rogge said the technical feat was achieved with a single atom of erbium – a commonly used in communications - embedded in silicon.

"We have the best of both worlds with our combination of an electrical and optical system. This is a revolutionary new technique, and people had doubts it was possible. It is the first step towards a global ," Professor Rogge said.

This video is not supported by your browser at this time.
An Australian team led by researchers at the University of New South Wales discuss their breakthrough in quantum science that brings the prospect of a network of ultra-powerful quantum computers -- connected via a quantum internet -- closer to reality. Credit: UNSW

Quantum computers promise to deliver an exponential increase in processing power over conventional computers by using a single electron or nucleus of an atom as the basic processing unit - a , or .

By performing multiple calculations simultaneously, quantum computers are expected to have applications in economic modelling, fast database searches, modelling of quantum materials and and drugs, and encryption and decryption of information.

In a qubit, information is stored in the spin, or , of the electron or nucleus. Due to a quantum property known as superposition, spin can not only be up or down, but in both states at once. To produce a functioning qubit, scientists must be able to control, or change, the and then detect, or "read" it.

Professor Rogge said researchers had previously used either an electrical or an optical method to read the spin of a single atom, but not both methods together.

Lead author of the study, UNSW's Dr Chunming Yin, said the new approach opens up the possibility of using light to couple the atoms, or qubits, together to form a quantum computer.

This image shows laser light addressing a single erbium atom in a silicon chip. Credit: UNSW

"Using light to transfer information in the quantum state is easier than doing it electrically. Ultimately this will lead to quantum communications over long distances," Dr Yin said.

Associate Professor Matthew Sellars, of the Australian National University, said it was a step towards connecting a solid state quantum computer to what will be the quantum internet.

"The quantum internet will allow separate quantum computers to be integrated and it will enable encrypted communications."

Quantum communication systems will become critical for providing secure communications for government, military, defence, finance business and health industries.

To make the new quantum device, Associate Professor Jeffrey McCallum at the University of Melbourne used an ion implanter to shoot erbium atoms into a standard industrial silicon transistor.

When the atom was in a particular and laser light was shone on it, an electron was knocked off the atom. This was detected electrically, by the silicon transistor switching on.

Professor Rogge said the breakthrough was made possible by combining the expertise of the three groups. The next step would be to control the spin of the erbium atom, which should be relatively straightforward, and also to replicate their results using a phosphorus atom embedded in silicon.

The researchers said it will be at least another decade before the potential of quantum computation is fully realised.

Explore further: Simon's algorithm run on quantum computer for the first time—faster than on standard computer

More information: dx.doi.org/10.1038/nature12081

Related Stories

A silicon platform for quantum computers

Apr 17, 2013

A team of Australian engineers at the University of New South Wales (UNSW) has demonstrated a quantum bit based on the nucleus of a single atom in silicon, promising dramatic improvements for data processing ...

Single electron reader opens path for quantum computing

Sep 27, 2010

Researchers from University of New South Wales (Australia), University of Melbourne (Australia), and Aalto University (Finland) have succeeded in demonstrating a high-fidelity detection scheme for the magnetic ...

Quantum age edges closer

Jan 05, 2010

(PhysOrg.com) -- The arrival of superfast quantum computing is closer following recent breakthroughs by an international team led by UNSW researchers.

Nature: Electronic read-out of quantum bits

Aug 16, 2012

Quantum computers promise to reach computation speeds far beyond that of today's computers. As they would use quantum effects, however, they would also be susceptible to external interferences. Information ...

Recommended for you

How the hummingbird achieves its aerobatic feats

8 hours ago

(Phys.org) —The sight of a tiny hummingbird hovering in front of a flower and then darting to another with lightning speed amazes and delights. But it also leaves watchers with a persistent question: How ...

New terahertz device could strengthen security

Nov 21, 2014

We are all familiar with the hassles that accompany air travel. We shuffle through long lines, remove our shoes, and carry liquids in regulation-sized tubes. And even after all the effort, we still wonder if these procedures ...

CERN makes public first data of LHC experiments

Nov 21, 2014

CERN today launched its Open Data Portal where data from real collision events, produced by experiments at the Large Hadron Collider (LHC) will for the first time be made openly available to all. It is expected ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.