Physics breakthrough much ado about 'nothing'

Mar 05, 2008

How do scientists store nothing? It may sound like the beginning of a bad joke, but the answer is causing a stir in the realm of quantum physics after two research teams, including one from the University of Calgary, have independently proven it’s possible to store a special kind of vacuum in a puff of gas and then retrieve it a split second later.

In our everyday life, light is completely gone when we turn it off. In the world of quantum physics, which governs microscopic particles, even the light that is turned off exhibits some noise. This noise brings about uncertainty that can cause trouble when trying to make extremely precise measurements.

Using crystals to manipulate laser light, researchers create a peculiar type of nothingness known as a “squeezed vacuum,” which under certain conditions, exhibits less noise than no light at all. A squeezed vacuum is employed in gravitation wave detection; it is also important in the booming field of quantum information technology, where it is used to carry information and to generate an even more mysterious quantum object, entangled light.

Building on the 2001 breakthrough of Harvard-Smithsonian scientists who slowed light down to a stop, teams of physicists from the U of C and the Tokyo Institute of Technology have independently demonstrated that a squeezed vacuum can be stored for some time in a collection of rubidium atoms and retrieved when needed. In work to be published in the March 7 advanced online edition of the leading physics journal Physical Review Letters, the physicists measured the noise of the retrieved light and found it to remain “squeezed” compared to no light at all.

“Memory for light has been a big challenge in physics for many years and I am very pleased we have been able to bring it one step further,” said Alexander Lvovsky, professor in the Department of Physics and Astronomy, Canada Research Chair and leader of the U of C’s Quantum Information Technology research group. “It is important not only for quantum computers, but may also provide new ways to make unbreakable codes for transmitting sensitive information”.

"I'm very impressed," physicist Alexander Kuzmich of the Georgia Institute of Technology in Atlanta told the American Association for the Advancement of Science’s ScienceNOW news service of the squeezed vacuum discovery. Kuzmich, who was able to store and retrieve a single photon in 2006, said the development could help create new types of quantum networks for ultra-secure information transmission and help spell out the boundary of the quantum realm. "It's a real technical achievement," he said.

Lvovsky’s team is continuing work on light storage and is now investigating the possibility of storing more complex forms of quantum light, such as entangled light, which has a wide range of applications for quantum computing and information exchange.

A pre-press copy of Lvovsky et al’s paper “Quantum memory for squeezed light” from the journal Physical Review Letters can be obtained online at: arxiv.org/abs/0709.2258

Source: University of Calgary

Explore further: Team invents microscopic sonic screwdriver

Related Stories

Dedication of Advanced LIGO

May 19, 2015

The Advanced LIGO Project, a major upgrade that will increase the sensitivity of the Laser Interferometer Gravitational-wave Observatories instruments by a factor of 10 and provide a 1,000-fold increase in the number of astrophysical ...

Researchers build new fermion microscope

May 13, 2015

Fermions are the building blocks of matter, interacting in a multitude of permutations to give rise to the elements of the periodic table. Without fermions, the physical world would not exist.

How we recreated the early universe in the laboratory

May 12, 2015

One of the all-time great mysteries in physics is why our universe contains more matter than antimatter, which is the equivalent of matter but with the opposite charge. To tackle this question, our international team of researchers have managed to create a plasm ...

Recommended for you

Researchers prove magnetism can control heat, sound

May 28, 2015

Phonons—the elemental particles that transmit both heat and sound—have magnetic properties, according to a landmark study supported by Ohio Supercomputer Center (OSC) services and recently published by ...

How researchers listen for gravitational waves

May 28, 2015

A century ago, Albert Einstein postulated the existence of gravitational waves in his General Theory of Relativity. But until now, these distortions of space-time have remained stubbornly hidden from direct ...

What's fair?: New theory on income inequality

May 27, 2015

The increasing inequality in income and wealth in recent years, together with excessive pay packages of CEOs in the U.S. and abroad, is of growing concern, especially to policy makers. Income inequality was ...

Scientists one step closer to mimicking gamma-ray bursts

May 27, 2015

Using ever more energetic lasers, Lawrence Livermore researchers have produced a record high number of electron-positron pairs, opening exciting opportunities to study extreme astrophysical processes, such ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.