Feeds

'Software amplifier' boosts quantum signals

Preserving entanglement for better comms

Providing a secure and efficient Helpdesk

Even in quantum communications, adjusting the parameters of Shannon's Theorem can help improve reach and range. A group of Australian National University (ANU) researchers has found a way to extend the reach of quantum communications by improving the signal-to-noise ratio of quantum systems.

Their work, published in Nature Photonics (abstract here), offers a protocol for noiseless amplification of quantum systems.

According to Professor Ping Koy Lam of the ANU, who spoke to The Register, the protocol developed by his team helps circumvent the fragility of entanglement, the property of quantum systems that's important for quantum communications, computing, and key distribution.

The record for preserving correlation, even in the low-noise environment of a fibre-optic cable, is about 260 km, Professor Lam explained, and even that's a remarkable achievement given how difficult it is to preserve entanglement. With noiseless amplification of the quantum system, “we hope to achieve perhaps twice that range of the channel.”

The ANU protocol is based on what Professor Lam described as “probabilistic amplification”. The problem with amplifying quantum objects is that you introduce a noise penalty as well, and noise destroys entanglement. This was outlined in a key 1982 paper by Carlton Caves.

ANU student with quantum comms apparatus

PhD student Helen Chrzanowski, one of Professor Lam's team,

with the ANU quantum communications setup.

Image: Australian National University

However, Professor Lam said, “you can circumvent this if you're prepared to sacrifice most of your data. For example, we might run the experiment 1,000 times, knowing that once out of that 1,000, the system will give you noiseless amplification.”

The ANU protocol implements a filter function, he said, and with the right filter shape, “you get the right statistical function – what you get out of the system is a probabilistic noiseless amplified signal”.

Rather than being implemented as a midpoint regeneration-style amplifier, the ANU probabilistic noiseless amplifier is implemented at endpoints.

And since the ANU solution is an algorithm rather than a particular physical setup, the results should be readily reproducible by other researchers with suitable environments. ®

Internet Security Threat Report 2014

More from The Register

next story
MARS NEEDS WOMEN, claims NASA pseudo 'naut: They eat less
'Some might find this idea offensive' boffin admits
LOHAN crash lands on CNN
Overflies Die Welt en route to lively US news vid
Comet Siding Spring revealed as flying molehill
Hiding from this space pimple isn't going to do humanity's reputation any good
Experts brand LOHAN's squeaky-clean box
Phytosanitary treatment renders Vulture 2 crate fit for export
No sail: NASA spikes Sunjammer
'Solar sail' demonstrator project binned
Carry On Cosmonaut: Willful Child is a poor taste Star Trek parody
Cringeworthy, crude and crass jokes abound in Steven Erikson’s sci-fi debut
Origins of SEXUAL INTERCOURSE fished out of SCOTTISH LAKE
Fossil find proves it first happened 385 million years ago
Human spacecraft dodge COMET CHUNKS pelting off Mars
Odyssey orbiter yet to report, though - comet's trailing trash poses new threat
prev story

Whitepapers

Forging a new future with identity relationship management
Learn about ForgeRock's next generation IRM platform and how it is designed to empower CEOS's and enterprises to engage with consumers.
Why and how to choose the right cloud vendor
The benefits of cloud-based storage in your processes. Eliminate onsite, disk-based backup and archiving in favor of cloud-based data protection.
Three 1TB solid state scorchers up for grabs
Big SSDs can be expensive but think big and think free because you could be the lucky winner of one of three 1TB Samsung SSD 840 EVO drives that we’re giving away worth over £300 apiece.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.