A team of scientists from from Harvard University and Sandia's Ion Beam Laboratory has embedded two silicon atoms in a diamond matrix, and demonstrated all the necessary components when creating a quantum bridge to link two different quantum computers together.
An ion beam implanter was used in blasting single ions on precise spots on the diamond substrate. The team used the implantation process to replace a carbon atom of the diamond with a larger silicon atom, causing the two carbon atoms on each side of the silicon atom to flee. The process left the silicon atom buffered against stray electrical currents with non-conducting vacancies.
"People have already built small quantum computers. Maybe the first useful one won't be a single giant quantum computer but a connected cluster of small ones," said Ryan Camacho, a Sandia researcher.
The quantum information can be distributed on a bridge, similar to a network, which could pave the way for new forms of quantum sensing, because the quantum correlations enable the atoms in the bridge to behave as a unit.
The atoms are embedded in a solid, but their behavior is similar to floating in a gas, which makes the electrons respond to the quantum stimuli without unwanted interactions with other matter. The implantation process posed the silicon atoms at the precise right place; it's possible to implant thousands of them in different convenient locations, in order to improve connections between quantum devices. The atoms are planted below the surface of the substrate and annealed in place.
In order to get to this successful formula, approximately 1,000 randomly occurring effects were tested on carbon atoms, searching for a strong enough emission that would allow transferring the reaction to the level of a single photon.
After the implantation of silicon atoms into the diamond substrate, the silicon electrons are bumped into the next higher atomic energy state. When returning to their initial lower energy state, randomized photons are emitted, carrying information through the frequencies.
The scientists carried out the experiment along with the optical and quantum measurements associated to it to count the exact number of the implanted ions inside the diamond substrate.
Sandia National Laboratories is a multimission laboratory operated by the Sandia Corporation. The joint research with colleagues from Harvard University led to the integrated platform, which serves to prove the scalable quantum nanophotonics silicon-vacancy color centers coupling to diamond nanodevices.
The paper was published in Science Magazine on Oct. 13.
The Ion Beam Laboratory is a facility designed to provide and operate the core facilities, while supporting the design and implementation of specific apparatus needed for experiments requested by scientists. As a result, it enables competencies in routine ion beam experiments and the versatility to cater to the individual researcher' needs and make studies like these possible.