Featured Research

from universities, journals, and other organizations

Physicists Squeeze Light To Quantum Limit

Date:
January 7, 2009
Source:
University of Toronto
Summary:
Physicists have demonstrated a way to squeeze light to the fundamental quantum limit, a finding that has potential applications for high-precision measurement, next generation atomic clocks, novel quantum computing and our most fundamental understanding of the universe.

A progression of squeezed triphoton states spiraling outwards. The quantum uncertainty in the triphotons can be represented as a blob on a sphere that becomes progressively "squeezed".
Credit: Victoria Feistner

A team of University of Toronto physicists have demonstrated a new technique to squeeze light to the fundamental quantum limit, a finding that has potential applications for high-precision measurement, next-generation atomic clocks, novel quantum computing and our most fundamental understanding of the universe.

Krister Shalm, Rob Adamson and Aephraim Steinberg of U of T΄s Department of Physics and Centre for Quantum Information and Quantum Control, publish their findings in the January 1 issue of the international journal Nature.

"Precise measurement lies at the heart of all experimental science: the more accurately we can measure something the more information we can obtain. In the quantum world, where things get ever-smaller, accuracy of measurement becomes more and more elusive," explains PhD graduate student Krister Shalm.

Light is one of the most precise measuring tools in physics and has been used to probe fundamental questions in science ranging from special relativity to questions concerning quantum gravity. But light has its limits in the world of modern quantum technology.

The smallest particle of light is a photon and it is so small that an ordinary light bulb emits billions of photons in a trillionth of a second.. "Despite the unimaginably effervescent nature of these tiny particles, modern quantum technologies rely on single photons to store and manipulate information. But uncertainty, also known as quantum noise, gets in the way of the information," explains Professor Aephraim Steinberg.

Squeezing is a way to increase certainty in one quantity such as position or speed but it does so at a cost. "If you squeeze the certainty of one property that is of particular interest, the uncertainty of another complementary property inevitably grows," he says.

In the U of T experiment, the physicists combined three separate photons of light together inside an optical fibre, to create a triphoton. "A strange feature of quantum physics is that when several identical photons are combined, as they are in optical fibres such as those used to carry the internet to our homes, they undergo an "identity crisis" and one can no longer tell what an individual photon is doing," Steinberg says. The authors then squeezed the triphotonic state to glean the quantum information that was encoded in the triphoton΄s polarization. (Polarization is a property of light which is at the basis of 3D movies, glare-reducing sunglasses, and a coming wave of advanced technologies such as quantum cryptography.)

In all previous work, it was assumed that one could squeeze indefinitely, simply tolerating the growth of uncertainty in the uninteresting direction. "But the world of polarization, like the Earth, is not flat," says Steinberg.

"A state of polarization can be thought of as a small continent floating on a sphere. When we squeezed our triphoton continent, at first all proceeded as in earlier experiments. But when we squeezed sufficiently hard, the continent lengthened so much that it began to "wrap around" the surface of the sphere," he says.

"To take the metaphor further, all previous experiments were confined to such small areas that the sphere, like your home town, looked as though it was flat. This work needed to map the triphoton on a globe, which we represented on a sphere providing an intuitive and easily applicable visualization. In so doing, we showed for the first time that the spherical nature of polarization creates qualitatively different states and places a limit on how much squeezing is possible," says Steinberg.

"Creating this special combined state allows the limits to squeezing to be properly studied," says Rob Adamson. "For the first time, we have demonstrated a technique for generating any desired triphoton state and shown that the spherical nature of polarization states of light has unavoidable consequences. Simply put: to properly visualize quantum states of light, one should draw them on a sphere."


Story Source:

The above story is based on materials provided by University of Toronto. Note: Materials may be edited for content and length.


Cite This Page:

University of Toronto. "Physicists Squeeze Light To Quantum Limit." ScienceDaily. ScienceDaily, 7 January 2009. <www.sciencedaily.com/releases/2009/01/090106145008.htm>.
University of Toronto. (2009, January 7). Physicists Squeeze Light To Quantum Limit. ScienceDaily. Retrieved October 20, 2014 from www.sciencedaily.com/releases/2009/01/090106145008.htm
University of Toronto. "Physicists Squeeze Light To Quantum Limit." ScienceDaily. www.sciencedaily.com/releases/2009/01/090106145008.htm (accessed October 20, 2014).

Share This



More Matter & Energy News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

3BL Media (Oct. 20, 2014) — Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-fuel Impala Video provided by 3BL
Powered by NewsLook.com
Would A Travel Ban Even Work In Stopping Ebola Spread?

Would A Travel Ban Even Work In Stopping Ebola Spread?

Newsy (Oct. 19, 2014) — The U.S. currently isn't banning travel from Ebola-stricken areas, but it's at least being considered. Some argue though it could be counterproductive. Video provided by Newsy
Powered by NewsLook.com
Tech Giants Push Back After FBI Suggests Less Encryption

Tech Giants Push Back After FBI Suggests Less Encryption

Newsy (Oct. 19, 2014) — FBI Director James Comey's stance on encryption technology isn't receiving much support from the tech community. Video provided by Newsy
Powered by NewsLook.com
Microneedle Patch Promises Painless Pricks

Microneedle Patch Promises Painless Pricks

Reuters - Innovations Video Online (Oct. 18, 2014) — Researchers at The National University of Singapore have invented a new microneedle patch that could offer a faster and less painful delivery of drugs such as insulin and painkillers. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins