Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Entanglement Becomes Easier to Measure

22.03.2016

Physicists have developed a new protocol to detect entanglement of many-particle quantum states using a much easier approach. The protocol is particularly interesting for characterizing entanglement in systems involving many particles. These systems could help us not only to improve our understanding of matter but to develop measurement techniques beyond current existing technologies.

In quantum theory, interactions among particles create fascinating correlations known as entanglement that cannot be explained by any means known to the classical world. Entanglement is a consequence of the probabilistic rules of quantum mechanics and seems to permit a peculiar instantaneous connection between particles over long distances that defies the laws of our macroscopic world - a phenomenon that Einstein referred to as “spooky action at a distance.”


A new-found theoretical relation now allows extracting multiparticle entanglement with standard tools available in scattering experiments.

IQOQI/Ritsch

Developing protocols to detect and quantify entanglement of many-particle quantum states is a key challenge for current experiments because entanglement becomes very difficult to study when many particles are involved.

“We are able to control smaller particle ensembles well, where we can measure entanglement in a relatively straight forward way,” says quantum physicist Philipp Hauke. However, “when we are dealing with a large system of entangled particles, this measurement is extremely complex or rather impossible because the resources required scale exponentially with the system size.”

Philipp Hauke and Peter Zoller from the Department of Theoretical Physics at the University of Innsbruck and the Institute for Quantum Optics and Quantum Information (IQOQI) at the Austrian Academy of Sciences in collaboration with Markus Heyl from the Technical University of Munich, and Luca Tagliacozzo from ICFO - The Institute of Photonic Sciences have found a new way to detect certain properties of many-particle entanglement independent of the size of the system and by using standard measurement tools.

Entanglement measurable via susceptibility

“When dealing with more complex systems, scientists had to carry out a large number of measurements to detect and quantify entanglement between many particles,” says Philipp Hauke. “Our protocol avoids this problem and can also be used for determining entanglement in macroscopic objects, which was nearly impossible until now.”

With this new method theoretical physicists are able to use tools already well established experimentally. In their study, published in Nature Physics, the team of researchers give explicit examples to demonstrate their framework: The entanglement of many-particle systems trapped in optical lattices can be determined by laser spectroscopy, and the well-established technique of neutron scattering may be used for measuring it in solid-state systems.

As the physicists have been able to show, the quantum Fisher information, which represents a reliable witness for genuinely multipartite entanglement, is in fact measurable. The researchers have highlighted that entanglement can be detected by measuring the dynamic response of a system caused by a perturbation, which can be determined by comparing individual measurements. “For example, when we move a sample through a time-dependent magnetic field, we can determine the system’s susceptibility towards the magnetic field through the measurement data and thereby detect and quantify internal entanglement,” explains Hauke.

Manifold applications

Quantum metrology, i.e. measurement techniques with increased precision exploiting quantum mechanics, is not the only important field of application of this protocol. It will also provide new perspectives for quantum simulations, where quantum entanglement is used as a resource for studying properties of quantum systems. In solid-state physics, the protocol may be used to investigate the role of entanglement in many-body systems, thereby providing a deeper understanding of quantum matter.

The research work was supported by the Austrian Science Fund and the European Research Council.

Publication: Measuring multipartite entanglement via dynamic susceptibilities. Philipp Hauke, Markus Heyl, Luca Tagliacozzo, Peter Zoller. Advanced Online Publication, Nature Physics, on 21 March 2016. http://dx.doi.org/10.1038/nphys3700

Contact:
Philipp Hauke
Department of Theoretical Physics
University of Innsbruck
phone: +43 512 507 4787
email: philipp.hauke@uibk.ac.at

Christian Flatz
Public Relations
University of Innsbruck
phone: +43 512 507 32022
email: christian.flatz@uibk.ac.at

Weitere Informationen:

http://www.uibk.ac.at/th-physik/qo - Quantum Optics Theory Group, University of Innsbruck

Dr. Christian Flatz | Universität Innsbruck

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 >>>