This device is the size of a coin! Quantum entanglement of photons no longer requires a laboratory

Scientists from companies dealing with the development of new technologies using the phenomenon of quantum entanglement argue that the entanglement of superconducting qubits used so far may not be the most efficient solution. Instead, there is more and more talk of using photons for this. On the one hand, photon quantum states are stable, and on the other hand, photons are suitable for communication applications using the already popular optical fiber technology.

Who needs this quantum entanglement?

Albert Einstein described the phenomenon of quantum entanglement as a frightening action at a distance. There is something real about this grim name. It is generally accepted that nothing travels faster than light. Not even information about any event can travel from one place to another faster than the speed of light. Meanwhile, if we are dealing with two entangled particles, their quantum states are bound together. If we change the quantum state of one particle, the quantum state of the other particle will also change, instantly, at the same instant, whether it is a centimeter, a kilometer, or a hundred million light-years away from the first particle. A change in the state of one particle immediately causes a change in the state of the other, although in theory the second particle should not know what is happening to the first particle until it receives information about the change in its state. This unique process allows for the creation of quantum communication technology that cannot be heard in any way. What more could you have asked for?

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Until now, the problem with applying quantum technology has been the bulky equipment needed to create pairs of photons. While pairs of photons can indeed be entangled with each other, a large conventional laser is required to emit the photons themselves. Its size makes it impossible to apply the technology to practical applications.

Suddenly everything shrank

in Latest scientific article Scientists have introduced the first hybrid photonic chip. Using two different techniques on a chip the size of a small coin, it was possible to fit a device that generates laser light and another that converts it into entangled photons. Simply put, part of the device is an indium phosphide photomultiplier that generates laser light. This system is attached to the part on which there are rings made of silicon nitride. A laser emitting indium phosphide rotates silicon nitride rings where noise is removed from it. In the final loop, two photons are emitted. As a result of their annihilation, a pair of entangled photons is created.

Also read: Quantum entanglement at your fingertips. The designed device is unimaginably thin

The scientists argue that although this is a huge achievement – they managed to reduce the laser source by nearly a thousand times – they still have a lot of work to do. After all, the chance of quantum technology getting out of the lab and being used in reasonably sized devices has come true. Just be patient a little bit.