Physicists have demonstrated for the first time the process of quantum teleportation from one silicon chip to another. Their system, built on the principles of integrated optics, uses a combination of nonlinear photon sources and linear quantum circuits. This design provides one of the highest teleportation accuracy to date. Work published in Nature Physics.
To build systems for processing and transmitting quantum information, scientists often use the principles of integrated optics. Optics has several significant advantages: for example, it allows you to scale the system, increasing its computational capacity. Working with quantum data in integrated optics, however, requires the implementation of several complex mechanisms. Such a system should be able to generate groups of single photons, control them, and then register.
In previous works, physicists have already faced the problem of creating a generator with sufficiently bright and distinguishable photons. In addition, combining a photon source with quantum circuits (recorders) within one compact device is a rather difficult task. Despite this, in 2014, scientists succeeded in quantum teleportation of a photon within a single silicon chip.
Now an international team of scientists led by Daniel Llewellyn of the University of Bristol has built a system that allows quantum teleportation from one chip to another. It consists of two parts - a transmitter (5 × 3 millimeters) and a receiver (3.5 × 1.5 millimeters). The transmitter is a network of nonlinear photon sources and linear quantum circuits.
First, two pairs of photons are generated and passed through a sensor to determine if they are entangled. They are then directed through the waveguide channels to a linear quantum circuit (a sequence of quantum experiments). The last stage is measurement using a system of Mach-Zehnder interferometers (this device consists of a waveguide that branches into two parts; the electrodes located on the sides of the interferometer arms again bring the beam into a single one). One of the entangled photons is sent to the receiver over a 10-meter fiber optic cable. The receiver makes the same interferometer measurements as the transmitter.
Schematic representation of the device. and. transmitter b. receiver.
The installation can teleport photons within one and two chips (in the case of two chips, they were at a distance of 10 meters from each other). The degree of coincidence of quantum states (accuracy of teleportation) in the first mode is 0.906, in the second - 0.885. In the work on teleportation in 2014, physicists achieved a figure of about 0.89.
According to the authors, their work can be useful in larger-scale integrated optics projects that are applicable in the field of quantum communication and computation. We are talking not only about a quantum computer, but also about a quantum network implemented on optical principles. Improving the accuracy of data transmission will enable physicists to create more efficient communications based on quantum teleportation.
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