Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Quantum physics: Ménage à trois photon-style

16.10.2019

Physicists from UNIGE have discovered a new quantum property: By placing 3 pairs of photons in a network, it is possible to entangle them and create new ultra-strong correlations

Entanglement is one of the properties specific to quantum particles. When two photons become entangled, for instance, the quantum state of the first will correlate perfectly with the quantum state of the second, even if they are at a distance from one another. But what happens when three pairs of entangled photons are placed in a network?


A quantum network with a triangular structure allows for a fundamentally novel type of quantum correlations.

Credit: © UNIGE

Researchers at the University of Geneva (UNIGE), Switzerland, working in partnership with Tehran's Institute for Research in Fundamental Sciences (IPM), have proved that this arrangement allows for a new form of quantum correlation in theory.

When the scientists forced two photons from separate pairs to become entangled, the connection was also made with their twin photon present elsewhere in the network, forming a highly-correlated triangle. These results, which you can read all about in the journal Physical Review Letters, create the potential for new applications in cryptography while reviving quantum physics at its most fundamental level.

Entanglement involves two quantum particles - photons, for example - forming a single physical system in spite of the distance between them. Every action performed on one of the two photons has an impact on its "twin" photon.

This principle of entanglement leads to quantum non-locality: the measurements and statistics of the properties observed on one of the photons are very closely correlated with the measurements made on the other photon.

"Quantum non-locality was discovered theoretically by John Stewart Bell in 1964," begins Nicolas Brunner, associate professor in the Department of Applied Physics in UNIGE's Faculty of Science. "This showed that photon correlations are exclusively quantum in nature, and so can't be explained by conventional physics. This principle could be used to generate ultra-secure encryption keys."

Is it possible to force photons in a network to become entangled?

But what are the implications of this principle of quantum non-locality when several pairs of photons are placed in a network? "To answer this question, we devised an experiment involving three pairs of photons that were then separated and dispersed to three points forming a triangle", explains Marc-Olivier Renou, who is also a researcher in the Department of Applied Physics. "At each vertex, two photons from a different pair are processed together."

The physicists subsequently forced the two photons at each vertex of the triangle to entangle by making them interact with each other, before measuring them. They finally showed that the statistics arising from these measurements cannot be explained by any local physical theory.

In addition, these statistics are so strongly correlated that they could represent a new form of quantum correlations. "It could become a new version of Bell's theorem, specific to quantum networks", enthuses Nicolas.

This important theoretical discovery underlines the power of quantum correlations in networks, which far exceeds what researchers had originally thought possible. The next step will be to observe these phenomena in the laboratory.

"It's not going to be child's play, because conducting an experiment like this is still extremely difficult for the time being", concludes Nicolas Gisin, a professor in UNIGE's Department of Applied Physics.

Media Contact

Nicolas Brunner
Nicolas.Brunner@unige.ch
41-223-794-368

 @UNIGEnews

http://www.unige.ch 

Nicolas Brunner | EurekAlert!
Further information:
http://dx.doi.org/10.1103/PhysRevLett.123.140401

More articles from Physics and Astronomy:

nachricht First radio detection of an extrasolar planetary system around a main-sequence star
04.08.2020 | Max-Planck-Institut für Radioastronomie

nachricht The art of making tiny holes
04.08.2020 | Vienna University of 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: AI & single-cell genomics

New software predicts cell fate

Traditional single-cell sequencing methods help to reveal insights about cellular differences and functions - but they do this with static snapshots only...

Im Focus: TU Graz Researchers synthesize nanoparticles tailored for special applications

“Core-shell” clusters pave the way for new efficient nanomaterials that make catalysts, magnetic and laser sensors or measuring devices for detecting electromagnetic radiation more efficient.

Whether in innovative high-tech materials, more powerful computer chips, pharmaceuticals or in the field of renewable energies, nanoparticles – smallest...

Im Focus: Tailored light inspired by nature

An international research team with Prof. Cornelia Denz from the Institute of Applied Physics at the University of Münster develop for the first time light fields using caustics that do not change during propagation. With the new method, the physicists cleverly exploit light structures that can be seen in rainbows or when light is transmitted through drinking glasses.

Modern applications as high resolution microsopy or micro- or nanoscale material processing require customized laser beams that do not change during...

Im Focus: NYUAD astrophysicist investigates the possibility of life below the surface of Mars

  • A rover expected to explore below the surface of Mars in 2022 has the potential to provide more insights
  • The findings published in Scientific Reports, Springer Nature suggests the presence of traces of water on Mars, raising the question of the possibility of a life-supporting environment

Although no life has been detected on the Martian surface, a new study from astrophysicist and research scientist at the Center for Space Science at NYU Abu...

Im Focus: Manipulating non-magnetic atoms in a chromium halide enables tuning of magnetic properties

New approach creates synthetic layered magnets with unprecedented level of control over their magnetic properties

The magnetic properties of a chromium halide can be tuned by manipulating the non-magnetic atoms in the material, a team, led by Boston College researchers,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“Conference on Laser Polishing – LaP 2020”: The final touches for surfaces

23.07.2020 | Event News

Conference radar for cybersecurity

21.07.2020 | Event News

Contact Tracing Apps against COVID-19: German National Academy Leopoldina hosts international virtual panel discussion

07.07.2020 | Event News

 
Latest News

First radio detection of an extrasolar planetary system around a main-sequence star

04.08.2020 | Physics and Astronomy

The art of making tiny holes

04.08.2020 | Physics and Astronomy

Early Mars was covered in ice sheets, not flowing rivers

04.08.2020 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>