Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > 'Superdense' coding gets denser

Photo by L. Brian Stauffer
Paul Kwiat, a John Bardeen Professor of Physics and Electrical and Computer Engineering, has broken the record for the most amount of information sent by a single photon.
Photo by L. Brian Stauffer
Paul Kwiat, a John Bardeen Professor of Physics and Electrical and Computer Engineering, has broken the record for the most amount of information sent by a single photon.

Abstract:
The record for the most amount of information sent by a single photon has been broken by researchers at the University of Illinois. Using the direction of "wiggling" and "twisting" of a pair of hyper-entangled photons, they have beaten a fundamental limit on the channel capacity for dense coding with linear optics.

'Superdense' coding gets denser

CHAMPAIGN, IL | Posted on March 27th, 2008

"Dense coding is arguably the protocol that launched the field of quantum communication," said Paul Kwiat, a John Bardeen Professor of Physics and Electrical and Computer Engineering. "Today, however, more than a decade after its initial experimental realization, channel capacity has remained fundamentally limited as conceived for photons using conventional linear elements."

In classical coding, a single photon will convey only one of two messages, or one bit of information. In dense coding, a single photon can convey one of four messages, or two bits of information.

"Dense coding is possible because the properties of photons can be linked to one another through a peculiar process called quantum entanglement," Kwiat said. "This bizarre coupling can link two photons, even if they are located on opposite sides of the galaxy."

Using linear elements, however, the standard protocol is fundamentally limited to convey only one of three messages, or 1.58 bits. The new experiment surpasses that threshold by employing pairs of photons entangled in more ways than one (hyper-entangled). As a result, additional information can be sent and correctly decoded to achieve the full power of dense coding.

Kwiat, graduate student Julio Barreiro and postdoctoral researcher Tzu-Chieh Wei (now at the University of Waterloo) describe their recent experiment in a paper accepted for publication in the journal Nature Physics, and posted on its Web site.

Through the process of spontaneous parametric down conversion in a pair of nonlinear crystals, the researchers first produce pairs of photons simultaneously entangled in polarization, or "wiggling" direction, and in orbital angular momentum, or "twisting" direction. They then encode a message in the polarization state by applying birefringent phase shifts with a pair of liquid crystals.

"While hyper-entanglement in spin and orbital angular momentum enables the transmission of two bits with a single photon," Barreiro said, "atmospheric turbulence can cause some of the quantum states to easily decohere, thus limiting their likely communication application to satellite-to-satellite transmissions."

####

About University of Illinois
At Illinois, research shapes the campus identity, stimulates classroom instruction and serves as a springboard for public engagement activities throughout the world. Opportunities abound for graduate students to develop independent projects and launch their own careers as researchers while working alongside faculty and assisting in their research. Illinois continues its long tradition of groundbreaking accomplishments with remarkable new discoveries and achievements that inspire and enrich the lives of people around the world.

For more information, please click here

Contacts:
James E. Kloeppel
Physical Sciences Editor
217-244-1073


Paul Kwiat
217-333-9116

Copyright © University of Illinois

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Silk could improve sensitivity, flexibility of wearable body sensors August 20th, 2017

The power of perovskite: OIST researchers improve perovskite-based technology in the entire energy cycle, from solar cells harnessing power to LED diodes to light the screens of future electronic devices and other lighting applications August 18th, 2017

Gold nanostars and immunotherapy vaccinate mice against cancer: New treatment cures, vaccinates mouse in small proof-of-concept study August 18th, 2017

Researchers printed graphene-like materials with inkjet August 17th, 2017

Spintronics

Smart multi-layered magnetic material acts as an electric switch: New study reveals characteristic of islands of magnetic metals between vacuum gaps, displaying tunnelling electric current March 1st, 2017

First experimental proof of a 70 year old physics theory: First observation of magnetic phase transition in 2-D materials, as predicted by the Nobel winner Onsager in 1943 January 6th, 2017

Investigations of the skyrmion Hall effect reveal surprising results: One step further towards the application of skyrmions in spintronic devices December 28th, 2016

Electron highway inside crystal December 12th, 2016

Quantum Computing

Sensing technology takes a quantum leap with RIT photonics research: Office of Naval Research funds levitated optomechanics project August 10th, 2017

Clarifiying complex chemical processes with quantum computers August 3rd, 2017

Ultracold molecules hold promise for quantum computing: New approach yields long-lasting configurations that could provide long-sought “qubit” material July 27th, 2017

Into the quantum world with a tennis racket: Classical mechanics helps control quantum computers July 6th, 2017

Discoveries

Silk could improve sensitivity, flexibility of wearable body sensors August 20th, 2017

The power of perovskite: OIST researchers improve perovskite-based technology in the entire energy cycle, from solar cells harnessing power to LED diodes to light the screens of future electronic devices and other lighting applications August 18th, 2017

Gold nanostars and immunotherapy vaccinate mice against cancer: New treatment cures, vaccinates mouse in small proof-of-concept study August 18th, 2017

Researchers printed graphene-like materials with inkjet August 17th, 2017

Announcements

Silk could improve sensitivity, flexibility of wearable body sensors August 20th, 2017

The power of perovskite: OIST researchers improve perovskite-based technology in the entire energy cycle, from solar cells harnessing power to LED diodes to light the screens of future electronic devices and other lighting applications August 18th, 2017

Gold nanostars and immunotherapy vaccinate mice against cancer: New treatment cures, vaccinates mouse in small proof-of-concept study August 18th, 2017

Researchers printed graphene-like materials with inkjet August 17th, 2017

Quantum nanoscience

Sensing technology takes a quantum leap with RIT photonics research: Office of Naval Research funds levitated optomechanics project August 10th, 2017

Nanocrystalline LEDs: Red, green, yellow, blue ... August 7th, 2017

Scientists discover new magnet with nearly massless charge carriers July 29th, 2017

Ultracold molecules hold promise for quantum computing: New approach yields long-lasting configurations that could provide long-sought “qubit” material July 27th, 2017

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project