Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > An infallible quantum measurement

The new method allows for reliable statements about the entanglement in a system.
Fotonachweis: Uni Innsbruck/Ritsch
The new method allows for reliable statements about the entanglement in a system.

Fotonachweis: Uni Innsbruck/Ritsch

Abstract:
For quantum physicists, entangling quantum systems is one of their every day tools. Entanglement is a key resource for upcoming quantum computers and simulators. Now, physicists in Innsbruck/Austria and Geneva/Switzerland realized a new, reliable method to verify entanglement in the laboratory using a minimal number of assumptions about the system and measuring devices. Hence, this method witnesses the presence of useful entanglement. Their findings on this ‘verification without knowledge' has been published in Nature Physics.

An infallible quantum measurement

Innsbruck, Austria and Geneva, Switzerland | Posted on August 5th, 2013

Quantum computation, quantum communication and quantum cryptography often require entanglement. For many of these upcoming quantum technologies, entanglement - this hard to grasp, counter-intuitive aspect in the quantum world - is a key ingredient. Therefore, experimental physicists often need to verify entanglement in their systems. "Two years ago, we managed to verify entanglement between up to 14 ions", explains Thomas Monz. He works in the group of Rainer Blatt at the Institute for Experimental Physics, University Innsbruck. This team is still holding the world-record for the largest number of entangled particles. "In order to verify the entanglement, we had to make some, experimentally calibrated, assumptions. However, assumptions, for instance about the number of dimensions of the system or a decent calibration, make any subsequently derived statements vulnerable", explains Monz. Together with Julio Barreiro, who recently moved on the Max Planck Institute of Quantum Optics in Garching, and Jean-Daniel Bancal from the group of Nicolas Gisin at the University of Geneva, now at the Center for Quantum Technologies in Singapore, the physicists derived and implemented a new method to verify entanglement between several objects.
Finding correlations

The presented device-independent method is based on a single assumption: "We only have to make sure that we always apply the same set of operations on the quantum objects, and that the operations are independent of each other", explains Julio Barreiro. "However, which operations we apply in detail - this is something we do not need to know." This approach - called Device Independent - allows them to get around several potential sources of error, and subsequently wrong interpretations of the results. "In the end, we investigate the correlations between the settings and the obtained results. Once the correlations exceed a certain threshold, we know that the objects are entangled." For the experimentally hardly avoidable crosstalk of operations applied to levitating calcium ions in the vacuum chamber in Innsbruck, the Swiss theorist Jean-Daniel Bancal managed to adapt the threshold according to a worst-case scenario. "When this higher threshold is breached, we can claim entanglement in the system with high confidence", states Bancal.
Assumptions as Achilles heel

For physicists, such procedures that are based on very few assumptions are highly interesting. By being basically independent of the system, they provide high confidence and strengthen the results of experimentalists. "Assumptions are always the Achilles heel - be that for lab data or theory work", stresses Thomas Monz. "We managed to reduce the number of assumption to verify entanglement to a minimum. Our method thus allows for reliable statements about the entanglement in a system." In the actual implementation, the physicists in Innsbruck could verify entanglement of up to 6 ions. This new method can also be applied for larger systems. The technical demands, however, also increase accordingly.

####

For more information, please click here

Contacts:
Thomas Monz

43-512-507-52452

Jean-Daniel Bancal
Centre of Quantum Technologies
National University of Singapore
Tel.: +65 6516 5626


Christian Flatz
Public Relations
University of Innsbruck
Tel.: +43 512 507 32022
Mobil: +43 676 872532022

Copyright © University of Innsbruck

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

Publication: Demonstration of genuine multipartite entanglement with device-independent witnesses. Julio T. Barreiro, Jean-Daniel Bancal, Philipp Schindler, Daniel Nigg, Markus Hennrich, Thomas Monz, Nicolas Gisin, and Rainer Blatt. Advance Online Publication, Nature Physics 2013 (DOI: 10.1038/NPHYS2705):

Related News Press

News and information

Application of air-sensitive semiconductors in nanoelectronics: 2-D semiconductor gallium selenide in encapsulated nanoelectronic devices September 22nd, 2017

Researchers set time limit for ultrafast perovskite solar cells September 22nd, 2017

DNA triggers shape-shifting in hydrogels, opening a new way to make 'soft robots' September 21st, 2017

Physicists develop new recipes for design of fast single-photon gun Physicists develop high-speed single-photon sources for quantum computers of the future September 21st, 2017

Physics

New quantum phenomena in graphene superlattices September 18th, 2017

Bit data goes anti-skyrmions September 1st, 2017

Heating quantum matter: A novel view on topology: Physicists demonstrate how heating up a quantum system can be used as a universal probe for exotic states of matter August 22nd, 2017

Sensing technology takes a quantum leap with RIT photonics research: Office of Naval Research funds levitated optomechanics project August 10th, 2017

Quantum Computing

Physicists develop new recipes for design of fast single-photon gun Physicists develop high-speed single-photon sources for quantum computers of the future September 21st, 2017

First on-chip nanoscale optical quantum memory developed: Smallest-yet optical quantum memory device is a storage medium for optical quantum networks with the potential to be scaled up for commercial use September 11th, 2017

High-speed quantum memory for photons September 9th, 2017

Quantum detectives in the hunt for the world's first quantum computer September 8th, 2017

Discoveries

Application of air-sensitive semiconductors in nanoelectronics: 2-D semiconductor gallium selenide in encapsulated nanoelectronic devices September 22nd, 2017

Researchers set time limit for ultrafast perovskite solar cells September 22nd, 2017

DNA triggers shape-shifting in hydrogels, opening a new way to make 'soft robots' September 21st, 2017

Physicists develop new recipes for design of fast single-photon gun Physicists develop high-speed single-photon sources for quantum computers of the future September 21st, 2017

Announcements

Application of air-sensitive semiconductors in nanoelectronics: 2-D semiconductor gallium selenide in encapsulated nanoelectronic devices September 22nd, 2017

Researchers set time limit for ultrafast perovskite solar cells September 22nd, 2017

DNA triggers shape-shifting in hydrogels, opening a new way to make 'soft robots' September 21st, 2017

Physicists develop new recipes for design of fast single-photon gun Physicists develop high-speed single-photon sources for quantum computers of the future September 21st, 2017

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers

Application of air-sensitive semiconductors in nanoelectronics: 2-D semiconductor gallium selenide in encapsulated nanoelectronic devices September 22nd, 2017

Researchers set time limit for ultrafast perovskite solar cells September 22nd, 2017

DNA triggers shape-shifting in hydrogels, opening a new way to make 'soft robots' September 21st, 2017

Physicists develop new recipes for design of fast single-photon gun Physicists develop high-speed single-photon sources for quantum computers of the future September 21st, 2017

Quantum nanoscience

Physicists develop new recipes for design of fast single-photon gun Physicists develop high-speed single-photon sources for quantum computers of the future September 21st, 2017

New quantum phenomena in graphene superlattices September 18th, 2017

Quantum detectives in the hunt for the world's first quantum computer September 8th, 2017

'Nano-hashtags' could provide definite proof of Majorana particles: Eindhoven network of nanowires gives particles the space to exchange places August 23rd, 2017

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project