Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Decay used to construct quantum information

25.11.2013
Usually, when researchers work with quantum information, they do everything they can to prevent the information from decaying.

Now researchers at the Niels Bohr Institute, among others, have flipped things around and are exploiting the decay to create the so-called entanglement of atomic systems, which is the foundation for quantum information processing. The results are published in the scientific journal, Nature.


This is an artist's impression of the experiment. Four ions are trapped on a line. The outer Magnesium ions (green) cools the system by emitting light. Lasers are used to prepare the inner Beryllium ions (red) in an entangled state where one can not understand the state of the particles individually but have to consider the two ions as a whole. As opposed to previous experiments also the latter process happens by the emission of light.

Credit: (Credit NIST)

"When working with quantum information, you would normally seek to isolate the system from the environment in order to not get a disturbing interaction that can destroy the fragile quantum state. But this is very difficult to avoid completely. So we thought that you could perhaps take the opposite approach and instead of seeing decay as the enemy, look at it as a friend and take advantage of it," explains Anders Søndberg Sørensen, a professor of quantum optics at the Niels Bohr Institute at the University of Copenhagen.

Electrons leaping hither and thither

The problem is that the quantum system is affected by the environment and exchanges energy with it. The electrons in the atoms jump from one energy state to another and researchers consider this kind of jump to be decay, because the information stored in the electrons disappears into its surroundings.

"But with our method we let the quantum system 'talk' with its surroundings and create a control of the electrons' jumps so that they are precisely in the state we want them to be in, and in that way we make use of the interaction with the environment," explains PhD student Florentin Reiter, who developed the theoretical model for the method together with Anders Sørensen.

The research is a collaboration with the experimental research group lead by David Wineland (recipient of the Nobel Prize in physics last year) at the National Institute for Standards and Technology in Boulder Colorado, USA.

Kicking the electrons into place

The method is based on a chain of ions comprised of magnesium and beryllium. They are cooled down to near absolute zero at minus 273 degrees C. The magnesium atoms are just there as a kind of cooling element in the chain of ions, while the beryllium atoms are the active elements. Entanglement is created between the electrons of the beryllium ions using carefully controlled laser light.

"The trick lies in the combination of laser light," explains Florentin Reiter and continues "the electrons can be in four energy states and if they jump around and land in a 'wrong' state, they are simply 'kicked' by the laser and we continue until they are where they are supposed to be. In that way there is perfect entanglement. Unlike in the past, when you had to use carefully designed laser pulses to create entanglement, researchers can now just turn on the laser and grab a cup of coffee and when they come back the electrons are in the correct state."

Up until this point, the decay of quantum information has been the biggest obstacle to making a quantum computer. The new experiment is the first time the problem has been turned on its head and the decay has been used constructively in a quantum computer. The researchers hope that this might be a way to overcome some of the problems that have previously made it difficult to make quantum computers. The researchers are now working to make more advanced quantum information processors based on the same ideas. In particular, they hope that similar techniques can be used to correct errors in a quantum computer.

For more information contact:

Anders Søndberg Sørensen
Professor, Quantum Optics
Niels Bohr Institute
University of Copenhagen
+45 3532-5240
+45 2466-1377
anders.sorensen@nbi.dk
Florentin Reiter
PhD student
Quantum Optics
Niels Bohr Institute
University of Copenhagen
0046-7232-70262
reiter@nbi.dk

Gertie Skaarup | EurekAlert!
Further information:
http://www.nbi.dk

More articles from Physics and Astronomy:

nachricht Engineering team images tiny quasicrystals as they form
18.08.2017 | Cornell University

nachricht Astrophysicists explain the mysterious behavior of cosmic rays
18.08.2017 | Moscow Institute of Physics and Technology

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>