Featured Research

from universities, journals, and other organizations

Next Step To The Quantum Computer: University Of Bonn Physicists Build Quantum Data Memory

Date:
October 7, 2004
Source:
University Of Bonn
Summary:
Physicists from the University of Bonn have succeeded in taking a decisive step forward towards processing quantum information with neutral atoms: in the latest issue of the 'Physical Review Letters' vol. 93 (2004) they describe how they managed to set up a quantum register experimentally.

Dominik Schrader in the laser lab.
Credit: Photo courtesy of University Of Bonn

Physicists from the University of Bonn have succeeded in taking a decisive step forward towards processing quantum information with neutral atoms: in the latest issue of the 'Physical Review Letters' vol. 93 (2004) they describe how they managed to set up a quantum register experimentally. Their next aim is to construct a quantum gate in which two or more atoms interact with each other in a controlled way. By combining the register and gate there would then be all the basic components available for developing a quantum computer with neutral atoms.

Registers are the central memory of a computer. They consist of a series of elementary information cells which can each take one bit of information, i.e. a logical zero or one. In a register of eight bits' length, for example, a number between 0 and 255 can be stored – the 255 corresponds to a series of eight bits with the state of 1. In order to add two numbers three registers are normally required: two for the two addends and one more for the result.

'For our registers we use neutral atoms,' Dominik Schrader of the Bonn Institute of Applied Physics adds. An atom is a microscopic quantum system and can therefore store quantum information. In analogy with the 'bit' this is thus known as a 'qubit'. In addition to the classic information states of zero and one, qubits can also take up an arbitrary number of intermediate states, what are known as quantum mechanical superposition states.

Dominik Schrader has built the register together with Dr. Arno Rauschenbeutel in Professor Dieter Meschede's team. In their experiment the physicists first decelerated caesium atoms so that they were scarcely moving. Five of these 'cool' atoms were then loaded onto a laser beam, a stationary light wave consisting of many peaks and troughs – roughly comparable to a piece of corrugated cardboard. The atoms were 'trapped' inside the troughs and remained stationary, which the team was able to check with a highly sensitive digital camera.

With the aid of an additional laser the researchers then initialised the quantum register, i.e. they 'wrote' zeros on all the qubits. 'We were then able to store the quantum information desired in each qubit by using microwave radiation,' Dominik Schrader explains. So as to be able to manipulate the qubits individually and selectively, the physicists generated a localised magnetic field. 'Depending on the local strength of the magnetic field, the qubits only react to microwave radiation of a very specific frequency. By varying the microwave radiation we were thus able to write the qubits desired.' The resolution of this addressing technique is about two thousandths of a millimetre – over a length of one millimetre, therefore, several hundred qubits could be stored.

In order to check whether the register really had stored the information desired, the researchers bombarded the chain of atoms with laser light which only interacts with qubits in status 0. The laser photons shot these 0 atoms off the carrier beam, but left the 1 atoms unaffected. On the camera image only the atoms with a state of 1 were subsequently visible.

In their next step the physicists will now attempt to set up a quantum gate, in which two or more qubits of the register interact with each other in a controlled way. 'We hope to get there in two years,' Dominik Schrader says. 'Mind you, in a field like this you repeatedly come across difficulties which you would not previously have anticipated.' He is thus cagey in making a prediction about when a 'quantum computer' worthy of the name will begin to operate. However, it would probably have abilities which would make traditional computers look pretty puny – e.g. when factorising large numbers, where today's computers soon come up against their limitations.


Story Source:

The above story is based on materials provided by University Of Bonn. Note: Materials may be edited for content and length.


Cite This Page:

University Of Bonn. "Next Step To The Quantum Computer: University Of Bonn Physicists Build Quantum Data Memory." ScienceDaily. ScienceDaily, 7 October 2004. <www.sciencedaily.com/releases/2004/10/041007082711.htm>.
University Of Bonn. (2004, October 7). Next Step To The Quantum Computer: University Of Bonn Physicists Build Quantum Data Memory. ScienceDaily. Retrieved October 2, 2014 from www.sciencedaily.com/releases/2004/10/041007082711.htm
University Of Bonn. "Next Step To The Quantum Computer: University Of Bonn Physicists Build Quantum Data Memory." ScienceDaily. www.sciencedaily.com/releases/2004/10/041007082711.htm (accessed October 2, 2014).

Share This



More Computers & Math News

Thursday, October 2, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Mozilla Bets On Software To Sell Its Chromecast Competitor

Mozilla Bets On Software To Sell Its Chromecast Competitor

Newsy (Oct. 1, 2014) Mozilla's Matchstick streaming device is entering a crowded market. The company is banking on open-source software to rise above the competition. Video provided by Newsy
Powered by NewsLook.com
App Teaches Kindergarteners to Code

App Teaches Kindergarteners to Code

AP (Oct. 1, 2014) They can't all read yet, but soon kindergarteners may be able to create basic computer code. Researchers in Massachusetts developed an app that teaches young kids a simple computer programming language. (Oct. 1) Video provided by AP
Powered by NewsLook.com
Microsoft Goes For Familiarity Over Novelty In Windows 10

Microsoft Goes For Familiarity Over Novelty In Windows 10

Newsy (Sep. 30, 2014) At a special event in San Francisco, Microsoft introduced its latest operating system, Windows 10, which combines key features from earlier versions. Video provided by Newsy
Powered by NewsLook.com
French Apple Fans Discover the Apple Watch

French Apple Fans Discover the Apple Watch

AFP (Sep. 30, 2014) Apple fans in France discover the latest toy, the Apple Watch. The watch comes in two sizes and an array of interchangeable, fashionable wrist straps. Duration: 00:42 Video provided by AFP
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