Featured Research

from universities, journals, and other organizations

Fundamental Limitation To Quantum Computers

Date:
July 18, 2005
Source:
Netherlands Organization for Scientific Research
Summary:
Quantum computers that save their data in so-called quantum bits (or qubits) will be confronted with a fundamental limitation. This is the claim made by Dutch theoretical physicists from the Foundation for Fundamental Research on Matter (FOM) and Leiden University in an article recently published in the journal Physical Review Letters.

Electron microscope image of a qubit from Hans Mooij's research group at Delft University of Technology.
Credit: Image courtesy of Netherlands Organization for Scientific Research

Quantum computers that store information in so-called quantum bits (or qubits) will be confronted with a fundamental limitation. This is the claim made by Dutch theoretical physicists from the Foundation for Fundamental Research on Matter (FOM) and Leiden University in an article recently published in the journal Physical Review Letters.

Related Articles


A quantum computer can only function if the information exists for long enough to be processed. The so-called coherence of the qubit ensures that the quantum information remains intact. The researchers have now discovered that the coherence spontaneously disappears over the course of time and with this the stored information as well. This could pose a considerable problem for the development of a quantum computer.

A quantum computer makes use of the fact that a quantum mechanical system -an electron, an atom or even a larger system such as a superconducting quantum bit - can simultaneously exist in two states. Normally one of the two states disappears as soon as the system comes into contact with the outside world. The coherence then disappears as a result of the decoherence process and the information in a quantum bit is lost.

A quantum bit typically consists of a large number of particles, with an unavoidably large number of possibilities to be influenced by the environment and thus be subjected to decoherence. Jasper van Wezel, Jeroen van den Brink (FOM) and Jan Zaanen, all attached to the Lorentz Institute of Leiden University have now investigated whether it is possible to maintain the coherence in an isolated qubit.

Much to their surprise they discovered that the coherence tends to spontaneously disappear, even without external influences. The degredation process is linked to the occurrence of quantum mechanical spontaneous symmetry breaking. In classical physics an equivalent example of this process is spontaneous crystallisation in a solution. At a certain position a crystal is spontaneously formed, as a result of which the fluid structure is broken.

According to the researchers' predictions, the coherence in some highly promising concepts for qubits will disappear after about a second. Moreover, the smaller the qubits the faster that process occurs. All of this would seem to pose a fundamental limitation on the development of qubits. Experimental research will now have to demonstrate whether this phenomenon actually occurs.


Story Source:

The above story is based on materials provided by Netherlands Organization for Scientific Research. Note: Materials may be edited for content and length.


Cite This Page:

Netherlands Organization for Scientific Research. "Fundamental Limitation To Quantum Computers." ScienceDaily. ScienceDaily, 18 July 2005. <www.sciencedaily.com/releases/2005/07/050708060942.htm>.
Netherlands Organization for Scientific Research. (2005, July 18). Fundamental Limitation To Quantum Computers. ScienceDaily. Retrieved January 29, 2015 from www.sciencedaily.com/releases/2005/07/050708060942.htm
Netherlands Organization for Scientific Research. "Fundamental Limitation To Quantum Computers." ScienceDaily. www.sciencedaily.com/releases/2005/07/050708060942.htm (accessed January 29, 2015).

Share This


More From ScienceDaily



More Computers & Math News

Thursday, January 29, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Facebook Rides Video, Mobile Waves To A Huge Quarter

Facebook Rides Video, Mobile Waves To A Huge Quarter

Newsy (Jan. 29, 2015) Mobile advertising now accounts for almost three quarters of Facebook’s total ad revenue. Video provided by Newsy
Powered by NewsLook.com
Samsung Sees Profits Slide

Samsung Sees Profits Slide

Reuters - Business Video Online (Jan. 29, 2015) The world&apos;s largest smartphone maker Samsung Electronics posted its first annual earnings decline in three years, but healthy demand for its memory chips helped soften the blow. Meg Teckman reports. Video provided by Reuters
Powered by NewsLook.com
'Brand Blocker' Glasses Blur Ads in Real Time

'Brand Blocker' Glasses Blur Ads in Real Time

Buzz60 (Jan. 28, 2015) A team of college students design and build a pair of goggles that will obscure any corporate branding from your field of vision. Jen Markham (@jenmarkham) has the story. Video provided by Buzz60
Powered by NewsLook.com
iPhone Sales Give Apple Record Quarter

iPhone Sales Give Apple Record Quarter

AP (Jan. 28, 2015) Apple says staggering consumer demand for new iPhones has helped the company report record-smashing earnings for its latest quarter and primed its stock for a rally. (Jan. 28) 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:

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