Featured Research

from universities, journals, and other organizations

New 'switch' could power quantum computing: Light lattice traps atoms, builds networks of quantum information transmitters

Date:
April 9, 2014
Source:
Massachusetts Institute of Technology
Summary:
Using a laser to place individual rubidium atoms near the surface of a lattice of light, scientists have developed a new method for connecting particles -- one that could help in the development of powerful quantum computing systems. The new technique allows researchers to couple a lone atom of rubidium, a metal, with a single photon, or light particle.

Scientists have developed a new method of trapping rubidium atoms in a lattice of light, which could help the development of quantum computing.
Credit: Christine Daniloff/MIT

Using a laser to place individual rubidium atoms near the surface of a lattice of light, scientists at MIT and Harvard University have developed a new method for connecting particles -- one that could help in the development of powerful quantum computing systems.

The new technique, described in a paper published today in the journal Nature, allows researchers to couple a lone atom of rubidium, a metal, with a single photon, or light particle. This allows both the atom and photon to switch the quantum state of the other particle, providing a mechanism through which quantum-level computing operations could take place.

Moreover, the scientists believe their technique will allow them to increase the number of useful interactions occurring within a small space, thus scaling up the amount of quantum computing processing available.

"This is a major advance of this system," says Vladan Vuletic, a professor in MIT's Department of Physics and Research Laboratory for Electronics (RLE), and a co-author of the paper. "We have demonstrated basically an atom can switch the phase of a photon. And the photon can switch the phase of an atom."

That is, photons can have two polarization states, and interaction with the atom can change the photon from one state to another; conversely, interaction with the photon can change an atom's energy level from its "ground" state to its "excited" state. In this way the atom-photon coupling can serve as a quantum switch to transmit information -- the equivalent of a transistor in a classical computing system. And by placing many atoms within the same field of light, the researchers may be able to build networks that can process quantum information more effectively.

"You can now imagine having several atoms placed there, to make several of these devices -- which are only a few hundred nanometers thick, 1,000 times thinner than a human hair -- and couple them together to make them exchange information," Vuletic adds.

Using a photonic cavity

Quantum computing could enable the rapid performance of calculations by taking advantage of the distinctive quantum-level properties of particles. Some particles can be in a condition of superposition, appearing to exist in two places at the same time. Particles in superposition, known as qubits, could thus contain more information than particles at classical scales, and allow for faster computing.

However, researchers are in the early stages of determining which materials best allow for quantum-scale computing. The MIT and Harvard researchers have been examining photons as a candidate material, since photons rarely interact with other particles. For this reason, an optical quantum computing system, using photons, could be harder to knock out of its delicate alignment. But since photons rarely interact with other bits of matter, they are difficult to manipulate in the first place.

In this case, the researchers used a laser to place a rubidium atom very close to the surface of a photonic crystal cavity, a structure of light. The atoms were placed no more than 100 or 200 nanometers -- less than a wavelength of light -- from the edge of the cavity. At such small distances, there is a strong attractive force between the atom and the surface of the light field, which the researchers used to trap the atom in place.

Other methods of producing a similar outcome have been considered before -- such as, in effect, dropping atoms into the light and then finding and trapping them. But the researchers found that they had greater control over the particles this way.

"In some sense, it was a big surprise how simple this solution was compared to the different techniques you might envision of getting the atoms there," Vuletic says.

The result is what he calls a "hybrid quantum system," where individual atoms are coupled to microscopic fabricated devices, and in which atoms and photons can be controlled in productive ways. The researchers also found that the new device serves as a kind of router separating photons from each other.

"The idea is to combine different things that have different strengths and weaknesses in such a way to generate something new," Vuletic says, adding: "This is an advance in technology. Of course, whether this will be the technology remains to be seen."

'Still amazing' to hold onto one atom

The paper, "Nanophotonic quantum phase switch with a single atom," is co-authored by Vuletic; Tobias Tiecke, a postdoc affiliated with both RLE and Harvard; Harvard professor of physics Mikhail Lukin; Harvard postdoc Nathalie de Leon; and Harvard graduate students Jeff Thompson and Bo Liu.

The collaboration between the MIT and Harvard researchers is one of two advances in the field described in the current issue of Nature. Researchers at the Max Planck Institute of Quantum Optics in Germany have concurrently developed a new method of producing atom-photon interactions using mirrors, forming quantum gates, which change the direction of motion or polarization of photons.

If the research techniques seem a bit futuristic, Vuletic says that even as an experienced researcher in the field, he remains slightly awed by the tools at his disposal.

"For me what is still amazing, after working in this for 20 years," Vuletic reflects, "is that we can hold onto a single atom, we can see it, we can move it around, we can prepare quantum superpositions of atoms, we can detect them one by one."


Story Source:

The above story is based on materials provided by Massachusetts Institute of Technology. The original article was written by Peter Dizikes. Note: Materials may be edited for content and length.


Journal Reference:

  1. T. G. Tiecke, J. D. Thompson, N. P. de Leon, L. R. Liu, V. Vuletić, M. D. Lukin. Nanophotonic quantum phase switch with a single atom. Nature, 2014; 508 (7495): 241 DOI: 10.1038/nature13188

Cite This Page:

Massachusetts Institute of Technology. "New 'switch' could power quantum computing: Light lattice traps atoms, builds networks of quantum information transmitters." ScienceDaily. ScienceDaily, 9 April 2014. <www.sciencedaily.com/releases/2014/04/140409134734.htm>.
Massachusetts Institute of Technology. (2014, April 9). New 'switch' could power quantum computing: Light lattice traps atoms, builds networks of quantum information transmitters. ScienceDaily. Retrieved August 1, 2014 from www.sciencedaily.com/releases/2014/04/140409134734.htm
Massachusetts Institute of Technology. "New 'switch' could power quantum computing: Light lattice traps atoms, builds networks of quantum information transmitters." ScienceDaily. www.sciencedaily.com/releases/2014/04/140409134734.htm (accessed August 1, 2014).

Share This




More Matter & Energy News

Friday, August 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Britain Testing Driverless Cars on Roadways

Britain Testing Driverless Cars on Roadways

AP (July 30, 2014) British officials said on Wednesday that driverless cars will be tested on roads in as many as three cities in a trial program set to begin in January. Officials said the tests will last up to three years. (July 30) Video provided by AP
Powered by NewsLook.com
7 Ways to Use Toothpaste: Howdini Hacks

7 Ways to Use Toothpaste: Howdini Hacks

Howdini (July 30, 2014) Fresh breath and clean teeth are great, but have you ever thought, "my toothpaste could be doing more". Well, it can! Lots of things! Howdini has 7 new uses for this household staple. Video provided by Howdini
Powered by NewsLook.com
Amid Drought, UCLA Sees Only Water

Amid Drought, UCLA Sees Only Water

AP (July 30, 2014) A ruptured 93-year-old water main left the UCLA campus awash in 8 million gallons of water in the middle of California's worst drought in decades. (July 30) Video provided by AP
Powered by NewsLook.com
Smartphone Powered Paper Plane Debuts at Airshow

Smartphone Powered Paper Plane Debuts at Airshow

AP (July 30, 2014) Smartphone powered paper airplane that was popular on crowdfunding website KickStarter makes its debut at Wisconsin airshow (July 30) Video provided by AP
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:
from the past week

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