MIPT ITF named after Landau: SQUID (Superconducting Diodes for Quantum Computers)

Main article: Quantum computers and quantum communication

2025: Making a "superconducting stealth diode"

B MIPT created a "superconducting invisible diode" for the quantum computers future. The university announced this on December 5, 2025.

Russian physicists have discovered a way to control electric current that will make quantum technologies more stable and efficient.

A diode is the simplest element in electronics, similar to a "road valve," which transmits current only in one direction. There are such elements in every smartphone and laptop. Its superconducting version - ultra-efficient and working without energy loss - was created by Russian scientists from MIPT and the Institute of Theoretical Physics named after L.D. Landau RAS. They did not just create such a diode, but discovered a hidden "superpower" in it, which manifests itself only in dynamics. The study paves the way for building components for next-generation computers.

Scientists have assembled a microscopic quantum system (SQUID) by combining two different superconducting elements. When they studied its standard properties, the "diode effect" (different conductivity in different directions) was weak. However, everything changed when the system was "shaken" with microwave radiation.

It turned out that in this dynamic mode the diode effect manifested itself ten times stronger. According to the developers, this can be compared to a door that you push with your hands with the same force in both directions, but if a strong wind blows at it, it will easily and quickly open in only one direction. Scientists have discovered this "invisible" asymmetry on the so-called "Shapiro steps" - features in the behavior of the system under radiation.

We have shown that the true potential of quantum systems is revealed not in statics, but in dynamics, - said the first author of the study, MIPT graduate student Dmitry Kalashnikov. - It's like discovering that the car has a hidden racing nitrous oxide function that only turns on on the track. Our work is a step towards creating energy-efficient quantum devices that run on their maximum capabilities.

Unlike traditional semiconductor diodes, superconducting analogs allow energy losses to be minimized. The innovative SQUID scientific group consisted of two fundamentally different elements: the Josephson transition with a sinusoidal characteristic and the nano bridge from niobium with a complex multivalued characteristic.

This discovery was made possible thanks to the hybrid structure that we created, - added Vasily Stolyarov, director of the Center for Advanced Methods of Mesophysics and Nanotechnology at MIPT. - We connected two different superconducting elements, and their interaction gave rise to this powerful effect. This is not just an observation, but the design of new quantum phenomena.

The study's findings pave the way for more stable quantum computers. Quantum computing is the main technological race of our time. Their main problem is the fragility of quantum states, which are easily destroyed due to external noise. Superconducting diodes operating in a dynamic mode open to scientists can become reliable "protective screens" for qubits (quantum bits), protecting them from interference and significantly increasing the stability of calculations.

Another area of ​ ​ application will be ultra-fast and energy-efficient electronics. Traditional electronics lose a huge amount of energy on heat. Superconducting circuits using this effect will be able to transmit and process signals without loss. This is critical for data centers, telecommunications equipment, and high-precision scientific instruments, reducing their power consumption and improving responsiveness.

Finally, the results of the study can be used to create new types of sensors. The system's high sensitivity to microwave radiation under certain conditions paves the way for ultra-accurate sensors for medicine (for example, magnetoencephalography that tracks brain activity) and security systems.

The work was carried out with the support of the Ministry of Science and Higher Education of the Russian Federation and the Russian Science Foundation.