MIPT and Terra Quantum: Quantum magnetometer

2021: Quantum magnetometer announcement

On April 5, 2021, it became known that physicists from MIPT and Terra Quantum, together with colleagues from the United States and Switzerland, developed an algorithm that allows measurements using artificial multilevel atoms. Such a quantum sensor allows you to obtain the necessary accuracy when measuring magnetic fields. It will also find application in brain research and in the study of outer space. The article was published in the journal Physical Review Research.

Superconducting atom

As explained, as of April 2021, quantum technologies are one of the most promising technologies of the future. The scientific community has already learned how to build quantum machines that surpass classic supercomputers in terms of processing power. One of the problems for which it turns out to be profitable to use quantum resources is the optimization of measurement accuracy. Important discoveries are often made thanks to high-precision instruments: telescopes help astronomers look deeper into space, biologists more and more accurately see the microworld using microscopes, and archaeologists need mass spectrometers to determine the age of minerals.

The classical measurement procedure is based on fundamental principles that do not allow overcoming the quadratic reduction of measurement error with an increase in measurement time. In other words, to double the accuracy of measurements, you need to take them four times longer. At the same time, the quantum approach allows you to double the accuracy of measurements, taking them only twice as long. It may seem that this is insignificant, but if it is necessary to increase the accuracy of the measurement by a thousand times, this means that the classical experiment will go a million times longer than the quantum one.

A team of researchers from MIPT and the Swiss company Terra Quantum has developed an algorithm for measuring magnetic fields using a multilevel superconducting atom.

Earlier, our group showed that the sensitivity of artificial atoms can be increased if we consider not a two-level system - a qubit, but a multi-level one. For example, a superconducting circuit that is actively used in quantum computing in qubit mode can be used in a three-level system mode. In this work, we proposed an algorithm for measuring magnetic fields using such multilevel systems. said Mikhail Perelstein, researcher at the Laboratory of Physics of Quantum Information Technologies MIPT, graduate student of the Physics and Research School named after Landau

We optimized the interaction time of the multilevel atom and the magnetic field at each step of the algorithm. It turned out that a linear increase in the interaction time at each step is an optimal procedure. As a result, the algorithm was called - Linear Ascending Metrological Algorithm, or simply LAMA. complemented by Nikita Kirsanov, one of the authors of the work, a researcher at the Laboratory of Quantum Information Technology Physics at the Moscow Institute of Physics and Technology and also a graduate student at the Physics and Research School named after Landau

Quantum magnetometers have many possible applications. Accuracy, and thus the speed of measurements, is especially important when working with sensitive samples and living tissues. For example, in the process of studying the brain, radioactive isotopes are introduced into the patient's blood, and the more precisely the sensor, the lower the required dose. Such a quantum magnetometer can be installed on a satellite, it will be able to collect information on astronomical phenomena at distances that are beyond the power of classical instruments. Moreover, a system of several quantum magnetometers can work as an ultra-sensitive spatial detector. Such devices are needed to do tomography for patients, analyze ore deposits, study the structure of biomolecules and inorganic materials.

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