Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

University of Toronto physicists take quantum leap toward ultra-precise measurement

03.06.2014

For the first time, physicists at the University of Toronto (U of T) have overcome a major challenge in the science of measurement using quantum mechanics. Their work paves the way for great advances in using quantum states to enable the next generation of ultra-precise measurement technologies.

"We've been able to conduct measurements using photons – individual particles of light – at a resolution unattainable according to classical physics," says Lee Rozema, a Ph.D. candidate in Professor Aephraim Steinberg's quantum optics research group in U of T's Department of Physics, and one of the lead authors along with M.Sc. candidate James Bateman of a report on the discovery published online today in Physical Review Letters. "This work opens up a path for using entangled states of light to carry out ultra-precise measurements."


University of Toronto physics students James Bateman (left) and Lee Rozema (right) led a study which successfully measured multiple photons in an entangled NOON state. The work paves the way for great advances in using quantum states to enable the next generation of ultra-precise measurement technologies.

Credit: Diana Tyszko

Many of the most sensitive measurement techniques in existence, from ultra-precise atomic clocks to the world's largest telescopes, rely on detecting interference between waves – which occurs, for example, when two or more beams of light collide in the same space. Manipulating interference by producing photons in a special quantum state known as an "entangled" state – the sort of state famously dismissed by a skeptical Albert Einstein as implying "spooky action at a distance" – provided the result Rozema and his colleagues were looking for. The entangled state they used contains N photons which are all guaranteed to take the same path in an interferometer – either all N take the left-hand path or all N take the right-hand path, but no photons leave the pack.

The effects of interference are measured in devices known as "interferometers." It is well known that the resolution of such a device can be improved by sending more photons through it – when classical light beams are used, increasing the number of photons (the intensity of the light) by a factor of 100 can improve the resolution of an interferometer by a factor of 10. However, if the photons are prepared in a quantum-entangled state, an increase by a factor of 100 should improve the resolution by that same full factor of 100.

The scientific community already knew resolution could be improved by using entangled photons. Once scientists figured out how to entangle multiple photons the theory was proved correct but only up to a point. As the number of entangled photons rose, the odds of all photons reaching the same detector and at the same time became astronomically small, rendering the technique useless in practice.

So Rozema and his colleagues developed a way to employ multiple detectors in order to measure photons in entangled states. They designed an experimental apparatus that uses a "fibre ribbon" to collect photons and send them to an array of 11 single-photon detectors.

"This allowed us to capture nearly all of the multi-photons originally sent," says Rozema. "Sending single photons as well as two, three and four entangled photons at a time into our device produced dramatically improved resolution."

The U of T experiment built on a proposal by National University of Singapore physicist Mankei Tsang. In 2009, Tsang posited the idea of placing detectors at every possible position a photon could reach so that every possible event could be recorded, whether or not multiple photons hit the same detector. This would enable the calculation of the average position of all the detected photons, and could be done without having to discard any of them. The theory was quickly tested with two photons and two detectors by University of Ottawa physicist Robert Boyd.

"While two photons are better than one, we've shown that 11 detectors are far better than two," says Steinberg, summarising their advancement on Boyd's results. "As technology progresses, using high-efficiency detector arrays and on-demand entangled-photons sources, our techniques could be used to measure increasingly higher numbers of photons with higher resolution."

The discovery is reported in a study titled "Scalable spatial superresolution using entangled photons" published in the June 6 issue of Physical Review Letters. It is recommended as an Editor's Suggestion, and is accompanied by a commentary in the journal Physics which describes the work as a viable approach to efficiently observing superresolved spatial interference fringes that could improve the precision of imaging and lithography systems.

###

In addition to Steinberg, Rozema and Bateman's collaborators on the research included Dylan Mahler, Ryo Okamoto of Hokkaido and Osaka Universities, Amir Feizpour, and Alex Hayat, now at the Technion - Israel Institute of Technology. Support for the research was provided by the Natural Sciences and Engineering Research Council of Canada and the Canadian Institute for Advanced Research, as well as the Yamada Science Foundation.

MEDIA CONTACTS:

Lee Rozema
Department of Physics
University of Toronto
lrozema@physics.utoronto.ca
416-946-3162

Aephraim Steinberg
Department of Physics
University of Toronto
steinberg@physics.utoronto.ca
416-978-0713

Sean Bettam
Communications, Faculty of Arts & Science
University of Toronto
s.bettam@utoronto.ca
416-946-7950

Sean Bettam | Eurek Alert!
Further information:
http://www.utoronto.ca

Further reports about: Physics detector detectors measurement measurements photons spatial techniques

More articles from Physics and Astronomy:

nachricht Further Improvement of Qubit Lifetime for Quantum Computers
09.12.2016 | Forschungszentrum Jülich

nachricht Electron highway inside crystal
09.12.2016 | Julius-Maximilians-Universität Würzburg

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: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

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

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>