Quantum systems

Quantum physics, including the wave approach to matter description, has always been an inviting area of application for Nizhny Novgorod scientific school of nonlinear oscillations and waves. 50-year-old works by V. L. Ginzburg, S. A. Zhevakin, V. V. Zheleznyakov, V. M. Fain, Ya. I. Khanin, and other researchers of the Radiophysics Research Institute (Nizhny Novgorod), as well as later works by A. A. Andronov, V. M. Gelikonov, O. A. Kocharovskaya, G. A. Pasmanik, G. I. Freidman, and other authors already present bright examples of analyzing complicated collective quantum phenomena and their classical analogs in electronics, atomic and nuclear physics, and in physics of lasers and semiconductors. Earlier studies performed by the IAP team in the fields of quantum optics and quantum electronics underpinned the recent advance in many fundamental and applied research lines of quantum physics.
In particular, IAP created the Russia-first setup for cooling of Fermi and Bose gases down to quantum degeneracy, and the world-first two-dimensional Fermi gas of atoms was produced. The methods of precision magnetometry, which are based on the effect of coherent population trapping, has been proposed and implemented. Solid-state logic elements and memory elements for quantum information and telecommunication systems are being developed. New methods for generation of extremely short electromagnetic pulses in the visible, X-ray, and gamma ranges have been developed, as well as new methods of generating of intense flows of correlated photons.
The long-standing problem of finding a microscopic theory of the second-order phase transitions has been solved for the first time. It allows one to describe spontaneous symmetry breaking and related critical phenomena in the whole critical region, starting from the disordered phase till a completely ordered phase. In particular, the problem of Bose-Einstein condensation and critical fluctuations in mesoscopic traps with an ideal gas has been solved analytically for the first time, and the universal structure of the thermodynamic and statistical quantities in the whole critical region around the critical lambda point has been identified. Unique properties have been found, and the possibility to make a laser on the Bose condensate of the active particles with the internal degrees of freedom has been demonstrated, in particular, a laser based on the traps for Bose condensation of dipolar excitons in semiconductor quantum wells. IAP researchers predicted, demonstrated for the first time (in the joint Russian-US experiments), and studied in detail the phenomenon of collective recombination of free electrons and holes in the magnetized semiconductor structures. A new class of lasers, superradiant D-class lasers, where the crucial role is played by the coherent dynamics of polarization of the quantum medium, has been studied, and the corresponding quantum theory has been developed, the expected regimes have been calculated, and the required heterostructures have been designed (jointly with the Physical-Technical Institute of RAS) for this class of devices. Several schemes of the efficient intracavity generation of the difference-frequency radiation in a wide IR range have been proposed and realized experimentally on the basis of the original semiconductor lasers jointly with the Institute of Physics of Microstructures of RAS (Nizhny Novgorod) and the R&D Physical-Technical Institute of Nizhny Novgorod State University.
In all these fields of quantum physics, IAP has gained leading positions in the Russian and world science and cooperates successfully with many scientific centers engaged in the studies of similar problems in Russia and abroad.