Physicists from Canada and Russia came up with a way to simplify the architecture of a quantum computer

© Photo : University of Amorebieta, Morandotti, Professor of the University ITMOPhysicists from Canada and Russia came up with a way to simplify the architecture of a quantum computer© Photo : ITMO University

Physicists from Russia and Canada have created the first silicon chip, able to store and manipulate multi-dimensional qubits, the elementary cell of the quantum memory that will allow to simplify the architecture of quantum computers to speed up their creation, according to a paper published in the journal Nature.

«At the moment we have learned to control the ten frequencies. In the system of two photons is provided StomperNet quantum States. Increasing the accuracy of manufacture of the resonator and the electronics responsible for the decomposition of the spectrum, it will be possible to work with almost a hundred different colors. It is this fine tuning will allow to increase the number of quantum States of the system,» says Roberto Morandotti (Roberto Morandotti), Professor of the University ITMO in Saint-Petersburg.

The qubits constituted both memory and compute modules of a quantum computer that can store and logical zero and the unit, thanks to the laws of quantum physics. Combine multiple qubits in the computational system allows you to quickly solve mathematical or physical problems, the answer using brute force would take time comparable to the lifetime of the Universe.

As told RIA «news» Alexey Ustinov, one of the leading scientists of the Russian quantum center, physics quickly learned how to produce single qubits, able to live long enough for doing calculations. On the other hand, attempts to combine several qubits are faced with great difficulties due to the fact that to write and read data from them is not as easy as it initially seemed.

For this reason, many scientists, including several physicists from Russia, go a different way — they do not link multiple qubits into a single network, and try to «stamp» a large number of cells of quantum information in one qubit. Relatively speaking, such qubits, which scientists call Cudicini or cutrite, can store not one range of values, and two, three or even more.

Morandotti, and his colleagues from foreign universities and scientific institutions have found a radical solution to this problem by creating a chip that allows you to «stamp» a virtually unlimited number of data pairs in the quantum entangled photons and read them when needed.

This chip, as they say scientists, represents microcavities — hollow silicon ring, inside which the light will move in a circle, Bouncing off the walls. The chip can be build so that certain pulses will be amplified and others suppressed, which makes it possible to obtain laser pulses with the «comb» spectrum, which is convenient to use to encode individual memory cells.

Due to this, the number of values encoded in a similar light qubit, it will depend on how well the devices will be able to see the light «comb» and to distinguish between the individual «teeth.»

In addition to the creation of quantum computers, like the resonators, and system of coding can be applied for other purposes, transmission of entangled photons over large distances and operate high-accuracy quantum lines. As a demonstration of scientists have developed a pair of entangled photons and transferred them to a distance of 24 kilometers, using conventional optical fiber.

The main problem of such multi-level qubits, how to recognize the physics is that particles of light may occasionally be lost during transmission over long distances, which imposes severe restrictions on the maximum number of particles that can simultaneously participate in the computation. On the other hand, this problem is offset by the fact that scientists can now work around this limitation, increasing the level of multidimensionality of qubits.

«By combining on a single chip generate multidimensional entangled photons with their ultra-fast processing, we showed that quantum systems can be controlled using standard telecommunication components such as modulators and frequency filters. This will facilitate the development and dissemination of technology,» concludes Jose Azana (Azana Jose), my colleague, Morandotti at the National research Institute of Canada in Quebec.