Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Improved interface for a quantum internet

15.01.2015

A quantum network requires efficient interfaces over which information can be transferred from matter to light and back. In the current issue of Physical Review Letters, Innsbruck physicists led by Rainer Blatt and Tracy Northup show how this information transfer can be optimized by taking advantage of a collective quantum phenomenon.

Quantum computers are no longer just a theoretical concept. In recent years, researchers have assembled and successfully tested the building blocks for a future quantum computer in the laboratory.


The experimental apparatus in which the researchers demonstrate a quantum interface.

Photo: IQOQI/Lackner


Two particles are positioned between highly reflective mirrors and entangled with one another by means of a laser.

Graphic: U. Innsbruck

More than a dozen candidate technologies are currently being studied; of these, ion traps are arguably the most advanced. In an ion trap, single atoms can be confined and precisely controlled by means of lasers. This idea was developed by theorists Ignacio Cirac and Peter Zoller, and a team of Innsbruck experimental physicists under Rainer Blatt has been at the forefront of its implementation.

Based at the University of Innsbruck’s Institute for Experimental Physics, the team first demonstrated in 2013 that quantum information stored in a trapped ion can be deterministically mapped onto a photon, that is, a quantum of light. Thus, they were able to construct an interface between quantum processors and optical fiber-based communication channels. Now the physicists have improved this interface, making use of so-called superradiant states.

A reliable interface

“In order to build a quantum network with trapped ions, we need an efficient interface that will allow us to transfer quantum information from ions to photons,” explains Tracy Northup, project leader in Rainer Blatt’s team. “In our interface, we position two ions between two highly reflective mirrors, which form an optical resonator. We entangle the ions with one another and couple both of them to the resonator.”

The collective interaction between the particles and the resonator can now be tuned in order to enhance the creation of single photons. “This is known as a superradiant state,” explains Bernardo Casabone, the article’s first author. In order to demonstrate that the interface is well suited for quantum information processing, the researchers encode a quantum state in the entangled particles and transfer this state onto a single photon.

Because of the superradiant interaction, the photon is generated almost twice as quickly as in their previous experiment. “Thanks to superradiance, the process of information transfer from the particle to the photon essentially becomes more robust,” Casabone emphasizes. As a consequence, the technical requirements for the construction of accurate interfaces may be relaxed.

Read–write capabilities for a quantum memory
In the same experiments on light–matter interactions, the Innsbuck physicists were also able to create so-called subradiant states. Here, the emission of a photon is suppressed rather than enhanced. “These states are also interesting because the stored information becomes invisible to the resonator, and in that sense, it’s protected,” says Northup. As a result, one can imagine that by switching between sub- and superradiant states, quantum information can be stored in ions and retrieved as photons. In a future quantum computer, such addressable read–write operations may be achieved for a quantum register of trapped ions.

The authors are based at the University of Innsbruck and at the Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences. Their research was supported by the Austrian Science Funds (FWF), the European Union, and Tirolean industry.

Publication: Enhanced quantum interface with collective ion-cavity coupling. B. Casabone, K. Friebe, B. Brändstatter, K. Schüppert, R. Blatt, and T. E. Northup. Phys. Rev. Lett. 114, 023602
http://dx.doi.org/10.1103/PhysRevLett.114.023602

Physics Synopsis: A Cavity Just for Two
http://physics.aps.org/synopsis-for/10.1103/PhysRevLett.114.023601

For further information, contact:
Tracy Northup
Institut für Experimentalphysik
Universität Innsbruck
Tel.: +43 512 507-52463
E-Mail: tracy.northup@uibk.ac.at

Christian Flatz
Büro für Öffentlichkeitsarbeit
Universität Innsbruck
Tel.: +43 512 507-32022
Mobil: +43 676 872532022
E-Mail: christian.flatz@uibk.ac.at

Weitere Informationen:

http://quantumoptics.at - Quantum Optics and Spectroscopy group
http://www.uibk.ac.at/exphys/ - Institut für Experimentalphysik, Universität Innsbruck

Dr. Christian Flatz | Universität Innsbruck

More articles from Physics and Astronomy:

nachricht NASA laser communications to provide Orion faster connections
30.03.2017 | NASA/Goddard Space Flight Center

nachricht Pinball at the atomic level
30.03.2017 | Max-Planck-Institut für Struktur und Dynamik der Materie

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: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

'On-off switch' brings researchers a step closer to potential HIV vaccine

30.03.2017 | Health and Medicine

Penn studies find promise for innovations in liquid biopsies

30.03.2017 | Health and Medicine

An LED-based device for imaging radiation induced skin damage

30.03.2017 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>