An entangled LED is a light-emitting diode containing a quantum dot that enables the production of entangled photons (light particles) on demand. According to researchers at Toshiba labs, where the device was developed, ELEDs could be used to create an optical quantum computer capable of performing in seconds tasks that would take a high-end conventional computer years to complete.
An LED is a semiconductor device that emits visible light when an electric current passes through it. The ELED is similar to a semiconductor LED but, with the application of an electrical charge, emits entangled photons. Although entangled LEDs have previously been created with lasers, the equipment required is too bulky and complex to be practical for quantum computing applications. The compact and simple nature of entangled LEDs make it possible to include large numbers of electronically addressable entangled light emitters on a single chip.
Entanglement is a phenomenon of quantum mechanics in which particles can become correlated to predictably interact with each other regardless of how far apart they are separated. If one entangled particle's spin state (the direction of its spin) is measured, we know that the spin of its mate is in the opposite direction. Harnessing that capacity could yield the enormous increase in processing power expected from quantum computing.
Other potential applications for entangled LEDs include quantum cryptography.