Quantum quirk contained: Discovery moves quantum networks closer to reality

January 12, 2011
Researchers at the University of Calgary and University of Paderborn designed a quantum memory device using a waveguide in a crystal doped with rare-earth ions. Credit: Wolfgang Tittel/University of Calgary

Researchers at the University of Calgary, in Canada, collaborating with the University of Paderborn, in Germany, are working on a way to make quantum networks a reality and have published their findings in the journal Nature. A similar finding by a group at the University of Geneva, in Switzerland is reported in the same issue.

“We have demonstrated, for the first time, that a crystal can store encoded into entangled quantum states of photons,” says paper co-author Dr. Wolfgang Tittel of the University of Calgary’s Institute for Quantum Information Science. “This discovery constitutes an important milestone on the path toward quantum networks, and will hopefully enable building quantum networks in a few years.”

In current communication networks, information is sent through pulses of light moving through optical fibre. The information can be stored on computer hard disks for future use.

Quantum networks operate differently than the networks we use daily.

“What we have is similar but it does not use pulses of light,” says Tittel, who is a professor in the Department of Physics and Astronomy at the University of Calgary. “In quantum communication, we also have to store and retrieve information. But in our case, the information is encoded into entangled states of photons.”

In this state, photons are “entangled,” and remain so even when they fly apart. In a way, they communicate with each other even when they are very far apart. The difficulty is getting them to stay put without breaking this fragile quantum link.

Wolfgang Tittel of the University of Calgary is researching ways of integrating quantum memory with current telecommunication technology. Credit: Riley Brandt/University of Calgary

To achieve this task, the researchers used a crystal doped with rare-earth ions and cooled it to -270 Celsius. At these temperatures, material properties change and allowed the researchers to store and retrieve these photons without measurable degradation.

An important feature is that this memory device uses almost entirely standard fabrication technologies. “The resulting robustness, and the possibility to integrate the memory with current technology such as fibre-optic cables is important when moving the currently fundamental research towards applications.”

will allow sending information without being afraid of somebody listening in.

“The results show that entanglement, a quantum physical property that has puzzled philosophers and physicists since almost hundred years, is not as fragile as is generally believed,” says Tittel.

Explore further: Quantum electronics: Two photons and chips

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not rated yet Jan 12, 2011
Might want to search the words,

Entangled Atomic Particle Communication and Holographic Quantum Memory

for prior work in the field.
1 / 5 (4) Jan 12, 2011
To achieve this task, the researchers used a crystal doped with rare-earth ions and cooled it to -270 Celsius.

Yeah, we all have liquid helium and microwave cooling apparatus in our closets so we can run our computers at temperatures colder than the surface of pluto.

This is sure to take off.
not rated yet Jan 12, 2011
Quantum networks in a few years? I am not sure if it was Dr. John E. Kelly III with IBM or if it was someone else at IBM that said quantum computers would not happen in their lifetime. He was about 55 years old a few years ago. I wonder what his estimate is now?
When I read the article about him I thought he would someday restate that remark again with a different time line.
Anyone out there who has a better time line for the arrival of quantum computers?
4 / 5 (1) Jan 13, 2011

To achieve this task, the researchers used a crystal doped with rare-earth ions and cooled it to -270 Celsius.

An important feature is that this memory device uses almost entirely standard fabrication technologies.

not rated yet Jan 13, 2011
To achieve this task, the researchers used a crystal doped with rare-earth ions and cooled it to -270 Celsius.
An important feature is that this memory device uses almost entirely standard fabrication technologies.


They did say ALMOST entirely standard fabrication technologies.
not rated yet Jan 18, 2011
my friend a quantum network and a quantum computer are two different things -- one refers to the ability to send information securely the other has to do with mimicking the quantum world for simulaitons. Networks are going to be easier to build than computers. And even then - most likely these giant machinges will be strictly for scientists -- but hey they said that about the computer before the advent of the PC
not rated yet Jan 19, 2011
I am quite familiar with the difference between quantum networks and quantum computers. I have an extensive background in security and my interest range from residential security to mind hacking. You might want to check out an article released today titled: First silicon entanglement will aid quantum computing.

I was curious when people thought quantum computers would become available? I believe future computers will be intertwined with quantum computers and classic computers, and that is only the beginning!

I find it very interesting to see what people have to say when future technologies will become available.
not rated yet Jan 20, 2011
wonder what the "rare-earth ion" could be.

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