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Issue 4, 2024

Triply heavy tetraquark spectroscopy

Triply heavy tetraquark spectroscopy

V. O. Galkin$^1$, E. M. Savchenko$^{1,2}$

Memoirs of the Faculty of Physics 2024. N 4.

The masses of the ground states of all possible compositions of triply heavy tetraquarks are calculated on the basis of the relativistic quark model and the diquark--antidiquark picture of tetraquarks. Within the framework of the quasipotential approach, the relativistic potential of the diquark--antidiquark interaction is constructed, which takes into account the internal structure of the diquark and antidiquark, as well as all spin--dependent and spin--independent relativistic corrections. The calculated masses of tetraquarks are compared with the heavy+heavy--light meson pair decay thresholds and conclusions are drawn about the possibility of experimental observation of such states.

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The Bose-Einstein polariton condensate is a promising optical medium for generating axion states.

The Bose-Einstein polariton condensate is a promising optical medium for generating axion states.

V. V. Volkova

Memoirs of the Faculty of Physics 2024. N 4.

Axion is a hypothetical neutral pseudoscalar particle postulated in quantum chromodynamics to solve the problem of preserving combined parity in quark-gluon interactions (a strong CP problem). It is assumed that the axion has a very small mass and interacts extremely weakly with other particles, which makes it an ideal candidate for the role of a dark matter particle (the non-baryonic component of the hidden mass in cosmology). In this paper, the possibility of laboratory generation of axions in a two-photon channel using a polariton Bose-Einstein condensate formed in a resonant photon trap as an active medium is investigated. Supporting calculations are presented. The results open up the possibility of obtaining axens in a ground-based optical laboratory.

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Super luminal sources of electromagnetic radiation in astrophysics

Super luminal sources of electromagnetic radiation in astrophysics

A. V. Terekhin$^1$, N. A. Kravets$^1$, V. A. Terekhin$^1$, V. A. Kuleshova$^2$, A. V. Soldatov$^1$, E. S. Stolmakova$^1$, I. V. Dolzhenkov$^1$

Memoirs of the Faculty of Physics 2024. N 4.

The report discusses simulation of electromagnetic radiation recorded from astrophysical superluminal sources in laboratory conditions. In particular, we focus on one of the theories of radio emission origin from pulsars, which assumes the generation of superluminal sources in a swirling plasma star. A generator of ultra-wideband electromagnetic pulses, patented by the Institute of General Physics of the Russian Academy of Sciences and the Russian Federal Nuclear Center -VNIIEF is proposed to consider as a laboratory device potentially capable of simulating such radiation. It is noted that in order to solve the problem, it is necessary to make changes to the technology for manufacturing experimental units of this generator. Preliminary estimates of characteristics of the modified structure of the specified generator are described and analyzed.

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Simulation of the Compton polarimeter SGS/Chibis-AI

Simulation of the Compton polarimeter SGS/Chibis-AI

A. A. Mkrtchyan$^{1,2}$, A. S. Pozanenko$^{1,2}$, P. Yu. Minaev$^2$

Memoirs of the Faculty of Physics 2024. N 4.

Despite many years of research on cosmic gamma-ray bursts, there are still many open questions about the model of gamma-ray generation by these sources. It is assumed that measuring the linear polarization of radiation can provide an answer to a number of unresolved questions in the physics of phenomena. The principle of registration of linear polarization of gamma radiation is based on the anisotropy of Compton scattering. This property is used to develop Compton polarimeters, which are an array of segmented scintillation detectors. In this paper, the authors conducted a simulation of the Compton polarimeter SGS/Chibis-AI, developed at the Space Research Institute of the Russian Academy of Sciences, using the Geant4 software package. The efficiency of detecting the polarization of gamma radiation with such a detector is being investigated.

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Development of the NTSim software package for modelling neutrino telescopes

Development of the NTSim software package for modelling neutrino telescopes

A. S. Belyakova$^1$, S. I. Zavyalov$^{2,3}$, D. V. Zubchenko$^2$

Memoirs of the Faculty of Physics 2024. N 4.

Experiments studying high-energy neutrino have become an important part of modern elementary particle physics. Simulation of various physical processes with detector's response is essential for obtaining results and data analysis. NTSim is a new software package under development for modelling neutrino telescopes. Though the initial aim has been to create simulation for Baikal-GVD experiment, the framework can be used for a wide range of detectors such as IceCube, KM3NeT/ARCA, HUNT and others. Main principles of NTSim design and work are described in this article.

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VVER-1200 Reactor Core Pin Cell Steady-State Thermal Hydraulics Analyses and Cross-Validation

VVER-1200 Reactor Core Pin Cell Steady-State Thermal Hydraulics Analyses and Cross-Validation

R. F. Siro, A. S. Zevyakin

Memoirs of the Faculty of Physics 2024. N 4.

A nuclear fuel element is designed with materials that are not only capable of withstanding extreme thermal stresses, but also effectively participating in heat transfer from the fuel to the coolant. Despite the poor thermal conductivity of gases relative to solids, it is necessary to include a gas gap in the fuel element to create room for accumulation of fission products. In this case, we have to consider an inert gas that is capable of transferring heat. Therefore, thermal hydraulics analysis becomes a prerequisite procedure for testing the possible violation of the established critical and maximum permissible parameters associated with the materials of the fuel element. To verify the safety of the VVER-1200 reactor core pin cell, the behavior of heat transfer from the fuel to the primary coolant was studied by solving the steady-state form of the heat conduction equation by analytical and numerical techniques. In the calculation schemes, the pin cell temperature distribution was established by solving for the temperature drop along the radial profile. The results revealed a VVER-1200 reactor core pin cell design exhibiting operations that do not violate the established permissible parameters associated with the adopted materials.

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Characteristics of propagation of regular amplitude- and phase-modulated optical fields obtained using a spatial light modulator

Characteristics of propagation of regular amplitude- and phase-modulated optical fields obtained using a spatial light modulator

A. A. Sharkov$^1$, V. I. Mokhov$^2$, O. M. Vokhnik$^3$

Memoirs of the Faculty of Physics 2024. N 4.

The change in the spatial distribution of laser radiation after passing through a spatial light modulator introducing regular two-dimensional amplitude-phase and pure phase modulation in the transverse plane of the beam was experimentally studied. The distance (Talbot distance) at which the two-dimensional transverse structure is reproduced for both modulation modes is determined. A comparison has been made of changes in the parameters of transverse spatial distributions for amplitude-phase-modulated and phase-modulated beams as they propagate. It is shown that the depth of modulation of the intensity distribution of amplitude-phase-modulated radiation is significantly higher than that of phase-modulated radiation, and this difference in contrast is maintained during radiation propagation. The results obtained can be used in problems of generating spatially structured radiation for contactless manipulation of particles in various media. Keywords: spatially modulated beams, two-dimensional light field, spatial light modulator, Talbot effect

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Features of express control of three-component mixture of volatile hydrocarbon media in visible light

Features of express control of three-component mixture of volatile hydrocarbon media in visible light

G. V. Stepanenkov, D. V. Vakorina, D. D. Tsyganova

Memoirs of the Faculty of Physics 2024. N 4.

The problems that arise in the express control of hydrocarbon media and their mixtures, in the case when the mixture consists of three components, are considered. One of the key features of measurements is the measurement of mixtures at different wavelengths. A system of equations was derived to determine the composition of the mixture under study. Refractive indices of various mixtures whose composition was known in advance were measured. The measurement results of different volatile hydrocarbon media and their mixtures of three components are presented. The result of the measurements and subsequent data analysis revealed the advantages and disadvantages of the method of express control of three-component mixtures of hydrocarbon media. A plan for further development of the method to solve the problems encountered, as well as its refinement and improvement was elaborated.

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Determination of the electric field strength on the side surface of the cathode in a glow discharge in helium at atmospheric pressure

Determination of the electric field strength on the side surface of the cathode in a glow discharge in helium at atmospheric pressure

P. A. Ivanova, A. V. Kazak, L. V. Simonchik, M. U. Tomkavich

Memoirs of the Faculty of Physics 2024. N 4.

The contours of the HeI 492.2 nm line formed by Stark σ components in the region of the cathode potential drop on the side surface of the cathode were recorded. A spectropolarization method has been developed for determining the electric field strength using the He I 492.2 nm line contour formed by Stark σ components. The spatial distribution of the electric field strength in the layer of cathode potential drop on the side surface of the cathode was obtained, which is linear with distance from the discharge gap.

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A new technique for controlling scale discreteness in a differential mobile refractometer

A new technique for controlling scale discreteness in a differential mobile refractometer

D. S. Provodin$^1$, M. A. Yakusheva$^2$, V. V. Davydov$^{1,2}$, D. D. Tsyganova$^2$

Memoirs of the Faculty of Physics 2024. N 4.

The necessity of measuring the refractive index of a liquid medium in the range from 1.230 to 2.830 with an accuracy of 0.0001 for unambiguous express monitoring of its state is substantiated. A methodology for controlling the discretization of the refractive indexmeasurement scale is proposed to transition from a measurement accuracy of 0.001 to 0.0001 without changing the laser and photodiode array or the distance between them. Using the new methodology on the previously developed design of a mobile refractometer with an Anderson differential cuvette, studies were conducted on various media and their mixtures. The results of the refractive index measurements obtained were compared with data from an industrial refractometer. The adequacy of the developed methodology and the feasibility of its use were confirmed.

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Development of a system for generating an excitation signal in a quantum frequency standard based on rubidium-87 atoms

Development of a system for generating an excitation signal in a quantum frequency standard based on rubidium-87 atoms

A. P. Valov$^1$, E. V. Isupova$^2$, V. V. Davydov$^1$

Memoirs of the Faculty of Physics 2024. N 4.

The need to modernize the frequency standard on rubidium-87 atoms in order to improve their metrological characteristics for use in satellite navigation systems is substantiated. A part of the excitation signal generation system for the rubidium frequency standard has been developed. An experimental study of the resulting system was carried out. It has been established that the use of a different system for generating the excitation signal makes it possible to reduce the level of phase noise, as well as reduce the overall dimensions of the frequency standard.

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Thermal radiation Transfer through the rain atmosphere in successive order scattering

Thermal radiation Transfer through the rain atmosphere in successive order scattering

Y. V. Kopcov$^1$, Y. A. ILYUSHIN$^{1,2}$, B. G. Kutuza$^2$

Memoirs of the Faculty of Physics 2024. N 4.

In the present work, the authors carried out a theoretical assessment of the thermal radio emission and precipitation intensity and polarization when observed by microwave radiometers from space. We propose to apply the method of successive order of scattering to simulate the microwave radiation of atmospheric clouds and rain. The authors carry out numerical modeling of the transfer of thermal radio emission in the rain atmosphere at a number of wavelengths. We have shown the effectiveness of the method and the solutions obtained in comparison with the finite difference method. It is shown that successive orders of scattering has a significant advantage for solving the tasks set.

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Устройство термостабилизации для стандарта частоты и времени

Устройство термостабилизации для стандарта частоты и времени

Е. В. Исупова$^1$, А. П. Валов$^2$

Memoirs of the Faculty of Physics 2024. N 4.

В статье обоснована необходимость улучшения устройства термостабилизации для стандарта частоты и времени на атомах рубидия-87. Рассмотрены различные принципы термостатирования: системы с регулированием по возмущению, отклонению и комбинированные. Выбран наилучший вариант. На его основе для борьбы с температурной нестабильностью, которая оказывает негативное влияние на оптические элементы в составе всего устройства, разработана новая схема термостабилизации для газовой ячейки квантового стандарта частоты. После проектирования печатных плат был произведён монтаж всех элементов. Лабораторные испытания квантового дискриминатора в термокамере показали отличную работу схемы, при которой изменение сопротивления терморезистора в мосте на 25% меньше, по сравнению со старой схемой. Доказана эффективность использования в схеме инструментального усилителя, который уменьшил сигнал ошибки в мосте, и ПИД-контроллера, который скорректировал переходные процессы и обеспечил стабильную и точную регуляцию в схеме, при этом защищая её от перерегулирования. С помощью термостабилизации в дальнейшем может быть улучшена кратковременная и долговременная стабильность стандарта частоты и времени, что благоприятно скажется на синхронизации временных шкал в спутниковой навигационной системе, которая опирается на точные измерения времени и расстояния для определения местоположения объекта, что имеет большое значение для таких областей, как авиация, морская навигация, геодезия, а также для повседневного использования GPS-устройств.

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Kinetic model of filament evolution in a percolation array of silver nanoparticles

Kinetic model of filament evolution in a percolation array of silver nanoparticles

P. O. Ksenofontova$^1$, Yu. O. Vasilevskaya$^2$, R. T. Sibatov$^2$

Memoirs of the Faculty of Physics 2024. N 4.

Self-organizing ensembles of nanoparticles have recently emerged as promising systems for realizing neuromorphic computing. The presence of memristive properties in the system is often associated with the formation and destruction of filaments in the gaps between nanoparticles. This work examines a simple model of the formation and destruction of filaments caused by the electromigration of ions and the diffusion of metal atoms within a dielectric material or on a substrate. Based on a comparison of solutions for the growth time with experimental data, the expressions for the dependence of the growth rate on voltage and temperature were refined.

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Longitudinal dependence of the electron fluxes of the Earth's outer radiation belt according to Meteor-M2

Longitudinal dependence of the electron fluxes of the Earth's outer radiation belt according to Meteor-M2

A. O. Belova$^1$, I. N. Myagkova$^2$

Memoirs of the Faculty of Physics 2024. N 4.

The present work uses data from the Meteor-M2 satellite, which had a circular polar orbit and recorded electron fluxes in various energy ranges. To obtain the longitudinal dependence of the fluxes, data were taken for the period June – July 2019, corresponding to the minimum of solar and geomagnetic activity. To solve this problem, a program has been developed to automate the process of data analysis and determine the areas where the satellite passes the outer radiation belt of the Earth. The dependence of electron fluxes on longitude and the McIlwain parameter L was obtained, and a formula for converting fluxes from one longitude to another was derived, which allows calculating the values of fluxes in subsequent sections of the orbit.

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Search for a criterion for the mass estimation of the primary cosmic ray nuclei by the extensive air shower direct Cherenkov light for the SPHERE-3 telescope

Search for a criterion for the mass estimation of the primary cosmic ray nuclei by the extensive air shower direct Cherenkov light for the SPHERE-3 telescope

O. V. Cherkesova, V. I. Galkin

Memoirs of the Faculty of Physics 2024. N 4.

SPHERE-3 detector, which is under design now, will incorporate not only a reflected Cherenkov light telescope but an imaging direct light telescope. In the present paper the length of the direct Cherenkov image is used as a parametr sensitive to the primary particle mass. A number of criteria for event separation by the primary masses is considered differing by the detector location with respect to the shower axis and their dependence on the types and values of the thresholds on the photon density and the pitch of the grid used for the description of the Cherenkov light angular distribution.

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Analysis of the beam path of Cherenkov light of extensive air shower reflected from the snow surface in the SPHERE-3 telescope.

Analysis of the beam path of Cherenkov light of extensive air shower reflected from the snow surface in the SPHERE-3 telescope.

T. A. Kolodkin, V. I. Galkin

Memoirs of the Faculty of Physics 2024. N 4.

The article analyzes the influence of the reflected Cherenkov light telescope in the SPHERE-3 project on the image geometry. The compression of the image geometry at the edges of the mosaic and the unevenness of the mosaic illumination are considered. By approximating the obtained data and comparing them with undistorted data, correcting functions were obtained that will be used when constructing the image.

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Measurement of the domain wall mobility in amorphous ribbons NiCoFeSiB using Kerr microscopy

Measurement of the domain wall mobility in amorphous ribbons NiCoFeSiB using Kerr microscopy

S. V. Samchenko, N. N. Perova, T. B. Shapaeva, N. S. Perov

Memoirs of the Faculty of Physics 2024. N 4.

The work is devoted to the study of magneto-optical (MO) and magnetic properties of the amorphous ribbons NiCoFeSiB obtained by quenching from a melt. Measurements on a magnetometer with a vibrating sample showed that the amorphous ribbon in question is characterized by a low value of coercive force and a high value of saturation magnetization. The magneto-optical properties of the ribbon were investigated using a magneto-optical Kerr microscope. It is established that the considered amorphous ribbon has a pronounced equilibrium domain structure, which is preserved in the absence of an external magnetic field. The domain wall dynamics in low-frequency magnetic fields (0.1, 0.5 and 1 Hz) of small amplitudes (up to 12 Oe) was studied. The dependences of the domain wall displacement vs time for different values of the external magnetic field amplitudes and frequencies were obtained and the dependences of the domain wall velocity vs the field amplitude were calculated. The possibility to determine the surface domain wall velocity for various sections of the studied amorphous ribbon has been confirmed. The described method of measuring the domain wall mobility makes it possible to study the dynamic characteristics of samples under various external conditions.

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Modeling of individual harmonics of the magnetoelectric effect using the COMSOL Multiphysics software package

Modeling of individual harmonics of the magnetoelectric effect using the COMSOL Multiphysics software package

M. V. Dzhaparidze, L. Yu. Fetisov, F. A. Fedulov

Memoirs of the Faculty of Physics 2024. N 4.

A new algorithm for calculating the magnetoelectric effect in the COMSOL Multiphysics software package is proposed. It was based on the compilation of a linear composition of solutions of differential equations obtained at various points in time describing the magnetoelectric effect. The advantage of the described method was the possibility of isolating individual components corresponding to different harmonics of the magnetoelectric signal from the general spectrum of the magnetoelectric voltage. During the work, this method was used to calculate the field and amplitude dependences of the amplitudes of the first three harmonics of the magnetoelectric effect in two-layer composite structures based on magnetostrictive nickel and various wide-band piezoelectric conductors (aluminum nitride, gallium nitride and gallium oxide). It is shown that the dependences obtained using the method described in the work do not contradict the data available today, therefore, this calculation method is suitable for modeling promising magnetoelectric systems and will be able to find wide application in the future.

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Angular dependences of indium phosphide sputtering by a gallium focused ion beam

Angular dependences of indium phosphide sputtering by a gallium focused ion beam

K. N. Lobzov, M. A. Smirnova, L. A. Mazaletsky, D. E. Pukhov

Memoirs of the Faculty of Physics 2024. N 4.

The angular dependences of the surface morphology, composition of the surface layer, and sputtering yield of indium phosphide during sputtering by a focused beam of gallium ions with an energy of 30 keV are experimentally obtained. Analysis of the surface was carried out using scanning electron microscopy and secondary ion mass spectrometry. Sputtering yields were determined by measuring the volume of sputtered craters. The experimental results are compared with mathematical simulating data in the TRIDYN. The influence of the choice of surface binding energy matrix on the simulation results is discussed.

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Antibunching of Single-Photon Emission from a Superconducting Artificial Atom in Two Directions in a Coplanar Microwave Waveguide

Antibunching of Single-Photon Emission from a Superconducting Artificial Atom in Two Directions in a Coplanar Microwave Waveguide

V. V. Voskresenskii$^1$, A. V. Vasenin$^{1,2}$, A. Yu. Dmitriev$^{1,3}$, A. -. Bolgar$^1$, O. V. Astafiev$^{1,2,3}$

Memoirs of the Faculty of Physics 2024. N 4.

An important tool for studying sources of both classical and quantum radiation is the temporal correlation functions. In the optical range, single-photon detectors are used for their measurement. In the microwave range, such efficient detectors do not yet exist. However, with detectors that measure the linear characteristics of the electromagnetic field, such as voltage, it is also possible to measure correlation functions. In this work, we demonstrate the phenomenon of antibunching using second-order correlation functions, measured by the technique we developed, for the radiation of an artificial superconducting atom, naturally divided in a one-dimensional coplanar waveguide.

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Inductively shunted transmon qubits with high anharmonicity

Inductively shunted transmon qubits with high anharmonicity

A. S. Kirkovskii$^1$, D. A. Kalacheva$^{1,2,5}$, G. P. Fedorov$^{1,2,3,4}$, S. V. Sanduleanu$^{1,2,3,4}$, A. Yu. Dmitriev$^{1,2,4}$, O. V. Astafiev$^{1,4,5}$

Memoirs of the Faculty of Physics 2024. N 4.

In this paper, we investigate a kinemon superconducting artificial atom. We focus on the symmetric case, where the external magnetic flux is equally distributed between the SQUID elements. By varying the energy parameters of the qubit, we identify four distinct operating modes. We determine which modes make the kinemon qubit suitable for application in quantum devices and maximize the anharmonicity for the top and bottom "sweet spots" within these modes. Additionally, we discuss how the optimal parameters are changed when we take into consideration fabrication errors. The optimized anharmonicity and charging energy values are several times higher than those of the transmon qubit fabricated using the same technology. We demonstrate that incorporating an inductive element into the qubit circuit suppresses charge dispersion. Therefore, we do not expect a decrease in the relaxation and dephasing times for kinemon qubits.

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Peculiarities of the dynamics of quantum states of Josephson nanosystems during their interaction with a non-classical electromagnetic field

Peculiarities of the dynamics of quantum states of Josephson nanosystems during their interaction with a non-classical electromagnetic field

I. A. Tereshchenko$^{1,2}$

Memoirs of the Faculty of Physics 2024. N 4.

The dynamics of quantum states of a Josephson superconducting nanosystem under the action of various non-classical fields is studied. Such consideration is promising from the point of view of developing methods for controlling the properties of the systems under consideration and their use in nanoelectronics, as well as for the development of quantum logic protocols. Theoretical modeling of the operation of planar circuits based on Josephson superconducting nanostructures outside the linear regime is carried out, and methods for controlling quantum states of higher dimension in such systems are developed. As an example of a Josephson nanostructure, a qubit-transmon is considered, made on the basis of a nanoscale superconducting Josephson contact, whose eigenstates can be described within the framework of a quantum anharmonic oscillator model and analyzed in terms of bosonic ladder operators of creation and annihilation of excitation. The peculiarities of the excitation dynamics of such structures due to the Kerr nonlinearity of the Josephson subsystem are revealed. The formation of states with different properties arising in the process of dynamics due to the effects of nonlinear phase modulation is shown. The possibility of significant noise suppression in the system below the shot noise level has been demonstrated. The possibility of controlling the excitation of states of the Josephson subsystem by varying the parameters of nonlinearity and frequency detuning has been discovered. The effect of establishing an energy balance between subsystems due to the presence of Kerr nonlinearity is revealed.

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Wave mixing effects in cascade systems of superconducting qubits

Wave mixing effects in cascade systems of superconducting qubits

T. R. Sabirov$^1$, A. Yu. Dmitriev$^{1,3}$, S. A. Gunin$^1$, A. V. Vasenin$^{1,2}$, O. V. Astafiev$^{1,2,3}$

Memoirs of the Faculty of Physics 2024. N 4.

In present work, we numerically simulated the nonlinear quantum-optical effect, -- wave mixing of propagating wave packets (two coherent and antibunched with a coherent signal) in a cascade system of superconducting atoms -- qubits. As a possible realization, we consider qubits in the transmon architecture interacting with the waveguide in the strong coupling regime, which allows us to study the scattering in the cascade system at the level of single quanta of electromagnetic radiation. The obtained wave mixing spectra demonstrate sensitivity to photon statistics in the waveguide -- the detuning of the peak from the center frequency corresponds to the number of photons involved in the process.

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