Feeds

'Software amplifier' boosts quantum signals

Preserving entanglement for better comms

Beginner's guide to SSL certificates

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. ®

Beginner's guide to SSL certificates

More from The Register

next story
Antarctic ice THICKER than first feared – penguin-bot boffins
Robo-sub scans freezing waters, rocks warming models
Your PHONE is slowly KILLING YOU
Doctors find new Digitillnesses - 'text neck' and 'telepressure'
SEX BEAST SEALS may be egging each other on to ATTACK PENGUINS
Boffin: 'I think the behaviour is increasing in frequency'
Reuse the Force, Luke: SpaceX's Elon Musk reveals X-WING designs
And a floating carrier for recyclable rockets
The next big thing in medical science: POO TRANSPLANTS
Your brother's gonna die, kid, unless we can give him your, well ...
NASA launches new climate model at SC14
75 days of supercomputing later ...
Britain's HUMAN DNA-strewing Moon mission rakes in £200k
3 days, and Kickstarter moves lander 37% nearer takeoff
prev story

Whitepapers

Driving business with continuous operational intelligence
Introducing an innovative approach offered by ExtraHop for producing continuous operational intelligence.
10 threats to successful enterprise endpoint backup
10 threats to a successful backup including issues with BYOD, slow backups and ineffective security.
Getting started with customer-focused identity management
Learn why identity is a fundamental requirement to digital growth, and how without it there is no way to identify and engage customers in a meaningful way.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?
Beginner's guide to SSL certificates
De-mystify the technology involved and give you the information you need to make the best decision when considering your online security options.