Featured Research

from universities, journals, and other organizations

Quantum entanglement only dependent upon area

Date:
September 15, 2013
Source:
University College London - UCL
Summary:
Physicists have developed a new method for determining the amount of entanglement – a quantum phenomenon connecting two remote partners, and crucial for quantum technology - within part of a one-dimensional quantum system.

Two researchers at UCL Computer Science and the University of Gdansk present a new method for determining the amount of entanglement -- a quantum phenomenon connecting two remote partners, and crucial for quantum technology -- within part of a one-dimensional quantum system.

Related Articles


In their paper, published this week in Nature Physics, Dr Fernando Brandão (UCL Computer Science) and Dr Michał Horodecki (Institute for Theoretical Physics and Astrophysics, University of Gdansk) demonstrate when the correlation between particles in a sample reduces exponentially with distance, the entanglement between one region and the rest of the sample only depends on the area of the boundary between them.

Characterising entangled states is essential for technologies such as quantum computation, quantum communication and quantum cryptography. Entanglement is also the difficulty behind making computer simulations of quantum systems. This finding shows that a large class of quantum systems (those with exponential decay of correlations) has only limited entanglement and so can be simulated easily.

The relationship between area and entanglement was suspected by researchers in this field based on the intuitive argument that if the correlation between particles in a system dropped off rapidly with distance, only nearby particles would be entangled with each other. Therefore, particles far away from a boundary would not participate in entanglement and only the boundary area would be relevant.

However, this tempting idea was undermined by the existence of a counterexample. This seemed to show that even when two regions could be separated by a layer wide enough to cut off nearly all correlation between them, observers would not be able to know as much about each region as they would if they were genuinely isolated. This 'data hiding' phenomenon is a key characteristic of entangled states, where a lack of knowledge of one partner affects what can be measured of the other.

This work resolves the apparent difficulty by combining recent findings from quantum information theory, originally developed for analyzing quantum communication protocols, showing that data hiding cannot hold once exponential decaying correlations are found in all different regions of the system.

Dr Brandão says: "We're very excited to have produced this method. It proves something that seemed to be intuitively true, but the reason why it is true has turned out to be quite different from the original intuition. The result also helps us identify cases where there is low entanglement. These are often good candidates for simulation using classical computers not capable of modeling the consequences of quantum phenomena."

Dr Horodecki says: "What I especially like about our result, is that, perhaps for the first time in this domain, we used solely information-theoretic techniques without assuming any specific physical properties of the system other than exponential decaying correlations. This makes the result very general."


Story Source:

The above story is based on materials provided by University College London - UCL. Note: Materials may be edited for content and length.


Journal Reference:

  1. Fernando G. S. L. Brandão, Michał Horodecki. An area law for entanglement from exponential decay of correlations. Nature Physics, 2013; DOI: 10.1038/nphys2747

Cite This Page:

University College London - UCL. "Quantum entanglement only dependent upon area." ScienceDaily. ScienceDaily, 15 September 2013. <www.sciencedaily.com/releases/2013/09/130915134224.htm>.
University College London - UCL. (2013, September 15). Quantum entanglement only dependent upon area. ScienceDaily. Retrieved December 22, 2014 from www.sciencedaily.com/releases/2013/09/130915134224.htm
University College London - UCL. "Quantum entanglement only dependent upon area." ScienceDaily. www.sciencedaily.com/releases/2013/09/130915134224.htm (accessed December 22, 2014).

Share This


More From ScienceDaily



More Computers & Math News

Monday, December 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Touch-Free Smart Phone Empowers Mobility-Impaired

Touch-Free Smart Phone Empowers Mobility-Impaired

Reuters - Innovations Video Online (Dec. 21, 2014) — A touch-free phone developed in Israel enables the mobility-impaired to operate smart phones with just a movement of the head. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Building Google Into Cars

Building Google Into Cars

Reuters - Business Video Online (Dec. 19, 2014) — Google's next Android version could become the standard that'll power your vehicle's entertainment and navigation features, Reuters has learned. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
After Sony Hack, What's Next?

After Sony Hack, What's Next?

Reuters - US Online Video (Dec. 19, 2014) — The hacking attack on Sony Pictures has U.S. government officials weighing their response to the cyber-attack. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Navy Unveils Robot Fish

Navy Unveils Robot Fish

Reuters - Light News Video Online (Dec. 18, 2014) — The U.S. Navy unveils an underwater device that mimics the movement of a fish. Tara Cleary reports. Video provided by Reuters
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:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

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