Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

October 14, 2016

ALBUQUERQUE, N.M. -- By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer but a connected cluster of small ones."

Distributing quantum information on a bridge, or network, could also enable novel forms of quantum sensing, since quantum correlations allow all the atoms in the network to behave as though they were one single atom.

The joint work with Harvard University used a focused ion beam implanter at Sandia's Ion Beam Laboratory designed for blasting single ions into precise locations on a diamond substrate. Sandia researchers Ed Bielejec, Jose Pacheco and Daniel Perry used implantation to replace one carbon atom of the diamond with the larger silicon atom, which causes the two carbon atoms on either side of the silicon atom to feel crowded enough to flee. That leaves the silicon atom a kind of large landowner, buffered against stray electrical currents by the neighboring non-conducting vacancies.

Though the silicon atoms are embedded in a solid, they behave as though floating in a gas, and therefore their electrons' response to quantum stimuli are not clouded by unwanted interactions with other matter.

"What we've done is implant the silicon atoms exactly where we want them," said Camacho. "We can create thousands of implanted locations, which all yield working quantum devices, because we plant the atoms well below the surface of the substrate and anneal them in place. Before this, researchers had to search for emitter atoms among about 1,000 randomly occurring defects -- that is, non-carbon atoms -- in a diamond substrate of a few microns to find even one that emitted strongly enough to be useful at the single photon level."

Once the silicon atoms are settled in the diamond substrate, laser-generated photons bump silicon electrons into their next higher atomic energy state; when the electrons return to the lower energy state, because all things seek the lowest possible energy level, they spit out quantized photons that carry information through their frequency, intensity and the polarization of their wave.

"Harvard researchers performed that experiment, as well as the optical and quantum measurements," said Camacho. "We did the novel device fabrication and came up with a clever way to count exactly how many ions are implanted into the diamond substrate."

Sandia researcher John Abraham and other Sandia researchers developed special detectors -- metal films atop the diamond substrate -- that showed the ion beam implants were successful by measuring the ionization signal produced by single ions.

"Pretty cool, huh?" said Camacho.

The journal Science thought so. The work is published in the current issue.
-end-
The work was supported by Sandia's Laboratory Directed Research and Development program. Some work was performed at the Center for Integrated Nanotechnologies (CINT), a Department of Energy Office of Science User Facility operated by Los Alamos and Sandia national laboratories.

Sandia National Laboratories is a multimission laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corp., for the U.S. Department of Energy's National Nuclear Security Administration. With main facilities in Albuquerque, N.M., and Livermore, Calif., Sandia has major R&D responsibilities in national security, energy and environmental technologies and economic competitiveness.

DOE/Sandia National Laboratories

Related Diamond Articles from Brightsurf:

Getting single-crystal diamond ready for electronics
Researchers from Osaka University and collaborating partners polished single-crystal diamond to near-atomic smoothness without damaging it.

Turning diamond into metal
Researchers have discovered a way to tweak tiny needles of diamond in a controlled way to transform their electronic properties, dialing them from insulating, through semiconducting, all the way to highly conductive, or metallic.

Building a harder diamond
Scientists at the University of Tsukuba create a theoretical carbon-based material that would be even harder than diamond.

Quantum diamond sensing
Researchers from the University of Maryland and colleagues report a new quantum sensing technique that allows high-resolution nuclear magnetic resonance spectroscopy on small molecules in dilute solution in a 10 picoliter sample volume -- roughly equivalent to a single cell.

Shining like a diamond: A new species of diamond frog from northern Madagascar
Despite the active ongoing taxonomic progress on the Madagascar frogs, the amphibian inventory of this hyper-diverse island is still very far from being complete.

The IKBFU scientists created the first diamond x-ray micro lens
A diamond is a unique and expensive material. But it is almost indestructible which makes the lens made of it more economically profitable than metallic or polymeric ones in the long run.

Stanford research maps a faster, easier way to build diamond
With the right amount of pressure and surprisingly little heat, a substance found in fossil fuels can transform into pure diamond.

Bending diamond at the nanoscale
A team of Australian scientists has discovered diamond can be bent and deformed, at the nanoscale at least.

A tech jewel: Converting graphene into diamond film
Can two layers of the ''king of the wonder materials,'' i.e. graphene, be linked and converted to the thinnest diamond-like material, the ''king of the crystals''?

Researchers teleport information within a diamond
Researchers from the Yokohama National University have teleported quantum information securely within the confines of a diamond.

Read More: Diamond News and Diamond Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.