Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


World record for the entanglement of twisted light quanta

To this end, the researchers developed a new method for entangling single photons which gyrate in opposite directions.
This result is a first step towards entangling and twisting even macroscopic, spatially separated objects in two different directions. The researchers at the Vienna Center for Quantum Science and Technology (VCQ), situated at the University of Vienna, and the Institute for Quantum Optics and Quantum Information (IQOQI) at the Austrian Academy of Sciences have were able to get their pioneering results published in the current issue of the renowned scientific journal Science.

Quantum physics is usually considered to be the theory of extremely lightweight objects, such as atoms or photons, or of exceptionally small units, namely very small quantum numbers. One of the most fascinating phenomena of quantum physics is that of entanglement. Entangled quanta of light behave as if able to influence each other – even as they are spatially separated.

False-color image of a laser beam exhibiting a superposition of 100 right-handed and 100 left-handed quanta of orbital angular momenta, resulting in 100+100=200 bright spots on the inner ring

Credit: Robert Fickler, University of Vienna

A long-exposure photo of laser light in 'donut modes' (light beams with no intensity in the middle).

Credit: Robert Fickler, University of Vienna

The question of whether or not entanglement is limited to tiny objects or very small quantum numbers came up already in the early days of quantum physics. Now, the Vienna group has taken the first step for testing quantum mechanical entanglement with rotating photons.

To illustrate, a quantum mechanical figure skater would have the uncanny ability to pirouette both clockwise and counter-clockwise simultaneously. Moreover, the direction of her rotations would be correlated with the twirls of another, entangled, skater – even if the two ice dancers whirl far removed from each other, in ice rinks on different continents.

The faster the two quantum skaters pirouette, the larger is the quantum number of their rotation direction, the so-called angular momentum. "In our experiment, we entangled the largest quantum numbers of any kind of particle ever measured," declares Zeilinger with a wry smile.

Could quantum ice dancers exist in reality?

It has been common knowledge for about 20 years now that theoretically, there is no upper limit for the angular momentum of photons. Previous experiments, however, have been limited, due to physical restrictions, to very weak angular momentum and small quantum numbers. In the Vienna experiment, it is theoretically possible to create entanglement regardless of the strength of the angular momentum or the scale of its quantum number. "Only our limited technical means stop us from creating entanglement with twisted photons that could be sensed even with bare hands," states Robert Fickler, the main author of the current Science publication. And so, the researchers have demonstrated that it is possible in principle to twirl entangled ice skaters simultaneously both in clockwise and counter-clockwise directions. In practice, a number of major challenges need to be addressed before such an experiment can be realized with macroscopic objects.

From fundamental research to technical applications

In addition to the fundamental issue of the limits of macroscopic entanglement, the physicists address possibilities of potential applications. They are, for example, able to use the created photons for very precise angular measurements already at low intensities of light. This feature is of advantage in particular when investigating light sensitive materials, as for example some biological substances. "The special features of entanglement provide the fantastic possibility to perform such measurements from arbitrary distances and without any contact whatsoever with the measured object, or even at a point in time that lies in the future!" Fickler explains.

This research was supported by the European Research Council (ERC) and the Austrian Science Fund (FWF).

Quantum Entanglement of High Angular Momenta
Robert Fickler, Radek Lapkiewicz, William N. Plick, Mario Krenn, Christoph Schaeff, Sven Ramelow, Anton Zeilinger to be published in Science/ 2nd november issue.
Further information:
Research Group Quantum Optics, Quantum Nanophysics & Quantum Information, Faculty of Physics, University of Vienna and Institute for Quantum Optics and Quantum Information (IQOQI), Austrian Academy of Sciences: Vienna Center for Quantum Science and Technology (VCQ):
Contact scientist:
Dipl. Phys. Robert Fickler
Quantum Optics, Quantum Nanophysics & Quantum Information
Faculty of Physics, University of Vienna
Institute for Quantum Optics and Quantum Information (ÖAW)
Boltzmanngasse 3, A-1090 Vienna, Austria
T 43-142-772-9568
Further enquiry note:
Verena Bock
Office Anton Zeilinger
Quantum Optics, Quantum Nanophysics & Quantum Information
Faculty of Physics, University of Vienna
Institute for Quantum Optics and Quantum Information (ÖAW)
Boltzmanngasse 3, A-1090 Vienna, Austria
T 43-142-775-1166

Veronika Schallhart | EurekAlert!
Further information:

More articles from Physics and Astronomy:

nachricht Scientists discover particles similar to Majorana fermions
25.10.2016 | Chinese Academy of Sciences Headquarters

nachricht Light-driven atomic rotations excite magnetic waves
24.10.2016 | 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: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Enormous dome in central Andes driven by huge magma body beneath it

25.10.2016 | Earth Sciences

First time-lapse footage of cell activity during limb regeneration

25.10.2016 | Life Sciences

Deep down fracking wells, microbial communities thrive

25.10.2016 | Earth Sciences

More VideoLinks >>>