Developed a fundamentally new type of qubit for a quantum computer

Developed a fundamentally new type of qubit for a quantum computer


An international group of scientists, consisting of Russian, British and German experts in the field of quantum technologies has created a revolutionary technology of qubits based on dzhozefsonovskikh the transition that represents the gap in the superconductor, and a continuous superconducting nanowire. About their work, the researchers shared in the journal Nature Physics.

In the world yet a universal quantum computer, able to cope with any tasks, however, developed methods and principles of computing now allow us to solve complicated tasks. For example, with qubits model chemical compounds and materials that recreate the mechanism of photosynthesis.

At the moment there are several types of qubits, but each of them has a drawback, which reduces the effectiveness of their work. For example, the generated qubits, capable of operating in the optical range, it is difficult to scale, in contrast to the qubits in superconductors, operating at radio frequencies and is based on the so-called Josephson junctions. Each such transition represents a gap of the superconductor, or rather, the dielectric layer through which electrons are tunneling.

A new type of qubit is based on the effect of quantum slippage of the phase – controlled periodic destruction and recovery of superconductivity in ultrathin (4 nm thick) of the nanowire, which in the normal state has a fairly large resistance.

Alexey Ustinov, is the co-author of the new work, the team leader, Russian quantum center, head of laboratory “Superconducting metamaterials” nust MISIS, Professor, Institute of technology Karlsruhe, said that now managed to create a new type of superconducting devices is similar to Squid (SQUID, Superconducting Quantum Interference Device — “superconductive quantum interferometer”).

The SQUID is a sensitive magnetometer based on Josephson junctions used for measuring weak magnetic fields. However, the interference of the new device is not a magnetic field, and electric, which changes the electrical charge on the island between the two nanowires. These nanowires are playing the device role of the Josephson junctions, but does not require the creation of discontinuities and can be made of a single layer of the superconductor.

Alexey Ustinov notes: this work was able to show that this system can work as a charge interferometer.

“If nanopoulos split into two sections and to do in the center of the thickening, then, changing the shutter charge on the thickening that we can actually do a periodic modulation of the process of quantum tunneling of the magnetic quanta through the wire, which in this work is observed”, — said the scientist.

This is a key moment, proving that the resulting controlled and coherent effect and that it can be used to create qubits of a new generation. Ustinov also said that the development has no less functionality than the previous one, but easier to manufacture. New technology can be the basis of working principle the whole set of elements of superconducting electronics.