Physicists squeeze light on quantum scale

Sep 21, 2012

An international team of physicists has pushed the boundaries on ultra-precise measurement by harnessing quantum light waves in a new way.

It is one thing to be able to measure spectacularly small distances using "squeezed" light, but it is now possible to do this even while the target is moving around.

An Australian-Japanese made the breakthrough in an experiment conducted at the University of Tokyo, the results of which have been published in an article, "Quantum-enhanced tracking" in the prestigious journal, Science.

Leader of the international theoretical team Professor Howard Wiseman, from Griffith University's Centre for , said this more precise technique for motion tracking will have many applications in a world which is constantly seeking smaller, better and faster technology.

"At the heart of all scientific endeavour is the necessity to be able to measure things precisely," Professor Wiseman said.

"Because the of a light beam changes whenever it passes through or bounces off an object, being able to measure that change is a very powerful tool."

"By using squeezed light we have broken the standard limits for precision phase tracking, making a fundamental contribution to science," he said. "But we have also shown that too much squeezing can actually hurt."

Dr Dominic Berry from Macquarie University has been collaborating with Professor Wiseman on the theory of this problem for many years.

"The key to this experiment has been to combine "phase squeezing" of with feedback control to track a moving phase better than previously possible," Dr Berry said.

"Ultra-precise quantum-enhanced measurement has been done before, but only with very small phase changes. Now we have shown we can track large phase changes as well," he said.

Professor Elanor Huntington from UNSW Canberra, who directed the Australian experimental contribution, is a colleague of Professor Wiseman in the Centre for Quantum Computation and Communication Technology.

"By using quantum states of light we made a more precise measurement than is possible through the conventional techniques using laser beams of the same intensity," Professor Huntington said.

Curiously, we found that it is possible to have too much of a good thing. Squeezing beyond a certain point actually degrades the performance of the measurement making it less precise than if we had used with no squeezing."

Explore further: When parallel worlds collide, quantum mechanics is born

Related Stories

Using quantum smoothing for optical phase estimation

Mar 11, 2010

(PhysOrg.com) -- "There are many situations where we need to measure the classical properties of a quantum system," Elanor Huntington tells PhysOrg.com. "Optical phase estimation is one of these techniques, and it is cen ...

Physicists are first to 'squeeze' light to quantum limit

Jan 02, 2009

(PhysOrg.com) -- 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 ...

Squeezed light from single atoms

Jun 30, 2011

(PhysOrg.com) -- Max Planck Institute of Quantum Optics scientists generate amplitude-squeezed light fields using single atoms trapped inside optical cavities.

Quantum interference fine-tuned by Berry phase

Jul 05, 2012

(Phys.org) -- A team from the University of Bristol’s Centre for Quantum Photonics (CQP) has experimentally demonstrated how to use Berry’s phase to accurately control quantum interference between different photons.

Recommended for you

Quantum holograms as atomic scale memory keepsake

Oct 21, 2014

Russian scientists have developed a theoretical model of quantum memory for light, adapting the concept of a hologram to a quantum system. These findings from Anton Vetlugin and Ivan Sokolov from St. Petersburg ...

1980s aircraft helps quantum technology take flight

Oct 20, 2014

What does a 1980s experimental aircraft have to do with state-of-the art quantum technology? Lots, as shown by new research from the Quantum Control Laboratory at the University of Sydney, and published in Nature Physics today. ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

ForFreeMinds
1 / 5 (1) Sep 22, 2012
This article would have been better if it described exactly how precise the measurement made with this technique was.