Researchers at the Tyndall National Institute have developed a scalable array of electrically driven quantum dots that can produce entangled photons, a development that could make entangling photons easier and accelerate progress toward quantum computing. The method uses easily-sourced materials and conventional semiconductor fabrication technologies, according to researcher Emanuele Pelucchi.
“We have engineered a scalable array of electrically driven quantum dots using easily-sourced materials and conventional semiconductor fabrication technologies, and our method allows you to direct the position of these sources of entangled photons,” Pelucchi said.
The team created quantum dot light-emitting diodes (QDLEDs) that produce entangled photons. The pyramid-shaped quantum dots—similar to those used in QDLED televisions—are electrified using nanotechnology to entangle the photons. These pyramidal structures give physicists control over the process, which has been significantly difficult to achieve.
“Being able to control the positions of the quantum dots and to build them at scale are key factors to underpin more widespread use of quantum computing technologies as they develop,” Pelucchi said.
Despite a known method for entangling particles, the task remains challenging. According to MIT Technology Review, photons emerge from the crystal in slightly different directions that cannot be easily predicted. Physicists collect photons from the two most likely points of appearance, but most entangled photons are lost.
As of June, the record for the most photons entangled at a time was 10. Previously, the record was eight, produced at a rate of around nine events per hour.
The new method offers physicists a degree of control and predictability over the entanglement process, which may lead to more efficient production and collection of entangled photons. Scaling up entanglement is a step toward quantum computing, which theoretically could perform more operations than there are atoms in the universe—far beyond the current 10-photon entanglement record.
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