Featured Research

from universities, journals, and other organizations

Method Found To "Purify" Partially Entangled States

Date:
March 6, 2001
Source:
University Of Illinois At Urbana-Champaign
Summary:
Entanglement, the bizarre quantum mechanical connection that can exist between particles, is an essential component in many quantum information processing applications, such as quantum computation, teleportation and cryptography. But the connection between the particles can become "noisy" or "dirty," degrading the quality of the entanglement and rendering it useless for quantum information processing.

Champaign, Il — Entanglement, the bizarre quantum mechanical connection that can exist between particles, is an essential component in many quantum information processing applications, such as quantum computation, teleportation and cryptography. But the connection between the particles can become "noisy" or "dirty," degrading the quality of the entanglement and rendering it useless for quantum information processing.

As reported in the Feb. 22 issue of the journal Nature, a team of researchers led by Paul Kwiat – now at the University of Illinois – has demonstrated a way to "purify" and restore maximally entangled states. "Entangled states tend not to remain pure, due to interactions with the environment," said Kwiat, a John Bardeen Professor of Electrical and Computer Engineering and Physics at the UI. "Just as the connection between two cell phones can become clouded with static and must be filtered, we have implemented a technique that cleans up the 'static' in entangled systems."

The concept of "entanglement" is perhaps the most bizarre feature of quantum mechanics, a generally accepted theory that replaces classical mechanics for microscopic phenomena. In quantum mechanics, the properties of entangled photons, for example, are inextricably linked to each other – even if the photons are located on opposite sides of the galaxy. In this sense, quantum mechanics is said to be "nonlocal."

In work performed at the Los Alamos National Laboratory, Kwiat and his colleagues – physics professor Nicolas Gisin and graduate student Andre Stefanov (both from the University of Geneva) and Salvador Barraza-Lopez, an undergraduate student from Mexico – investigated entanglement distillation and hidden nonlocality.

First, the researchers created pairs of polarization-entangled photons by passing a laser pulse through two adjacent nonlinear crystals. By varying the linear polarization of the laser pulse, they could change the degree of entanglement. Then, the researchers implemented a simple distillation procedure to filter out a smaller, but cleaner, subset of entangled photons.

"We basically used the procedure to throw away the unwanted part of the contribution, and what remained was in a perfectly entangled state," Kwiat said. "In this way, we demonstrated distillation of maximally entangled states from non-maximally entangled inputs."

When applied to partially mixed states, the distillation procedure generated states that subsequently demonstrated nonlocal correlations, even though the initial states did not, the researchers reported. Such hidden nonlocality had been postulated, but never before seen.

"What's remarkable is that our filtering procedure is a local process, performed individually on only one photon of a pair, and yet the nonlocal nature of quantum entanglement is preserved," Kwiat said. "The final signal is not as strong – because there are fewer photons – but the noise is clearly reduced."


Story Source:

The above story is based on materials provided by University Of Illinois At Urbana-Champaign. Note: Materials may be edited for content and length.


Cite This Page:

University Of Illinois At Urbana-Champaign. "Method Found To "Purify" Partially Entangled States." ScienceDaily. ScienceDaily, 6 March 2001. <www.sciencedaily.com/releases/2001/02/010226072054.htm>.
University Of Illinois At Urbana-Champaign. (2001, March 6). Method Found To "Purify" Partially Entangled States. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2001/02/010226072054.htm
University Of Illinois At Urbana-Champaign. "Method Found To "Purify" Partially Entangled States." ScienceDaily. www.sciencedaily.com/releases/2001/02/010226072054.htm (accessed July 29, 2014).

Share This




More Matter & Energy News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Climate Change Could Cost Billions, According To White House

Climate Change Could Cost Billions, According To White House

Newsy (July 29, 2014) A report from the White House warns not curbing greenhouse gas emissions could cost the U.S. billions. Video provided by Newsy
Powered by NewsLook.com
Stranded Whale Watching Boat Returns to Boston

Stranded Whale Watching Boat Returns to Boston

Reuters - US Online Video (July 29, 2014) Passengers stuck overnight on a whale watching boat return safely to Boston. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Baluchistan Mining Eyes an Uncertain Future

Baluchistan Mining Eyes an Uncertain Future

AFP (July 29, 2014) Coal mining is one of the major industries in Baluchistan but a lack of infrastructure and frequent accidents mean that the area has yet to hit its potential. Duration: 01:58 Video provided by AFP
Powered by NewsLook.com
Easier Nuclear Construction Promises Fall Short

Easier Nuclear Construction Promises Fall Short

AP (July 29, 2014) The U.S. nuclear industry started building its first new plants using prefabricated Lego-like blocks meant to save time and prevent the cost overruns that crippled the sector decades ago. So far, it's not working. (July 29) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins