Kahil M.E., Ammar S.A. «Motion of spinning density tensors in a Clifford space» Нелинейный мир, 22, № 3, с. 62-80 (2024)

A Clifford Space is counted to be a tempting approach to unify both micro-physics and macro-physics simultaneously. Such a tendency may be found in the realm of replacing vectors with poly-vectors. Accordingly, the problem of motion becomes essential to express the motion of extended particles rather than test particles. These equations are performed by using an equivalent Bazanski Lagrangian in a Clifford space. From this perspective, a generalized type an equation for spinning density tensors and spinning density deviation tensors are obtained. Spinning deviation tensors in a Clifford space may give a better performance to examine the problem of stability for spinning density tensors as expressed in terms of vectors defined in such a class of Riemannian geometry.

Kuzmin N.M., Sirotin D.S., Khoperskov A.V. «Efficiency of parallel computations of gravitational forces by treecode method in n-body models» Математическая физика и компьютерное моделирование (до 2017 г. Вестник Волгоградского государственного университета. Серия 1: Математика. Физика), 27, № 4, с. 39-55 (2024)

Modeling of collisionless galactic systems is based on the n-body model, which requires large computational resources due to the long-range nature of gravitational forces. The most common method for calculating gravity is the TreeCode algorithm, which provides a faster calculation of the force compared to the direct summation of contributions from all particles for n-body simulation. An analysis of the computational efficiency is performed for models with the number of particles up to 10⁸. We considered several processors with differentarchitectures in order to determine the performance of parallel simulations based on the OpenMP standard. An analysis of the use of extra threads in addition to physical cores shows an increase in simulation performance only when all logical threads are loaded, which doubles the total number of threads. This gives an increase in the efficiency of parallel computing by 20 percent on average.

Kravchenko E.A., Rubtsov G.I., Zhadan D.S. «Towards Baikal-Top: Feasibility Study of an Onshore Detector System for the Joint Registration of EAS with Baikal-GVD» Журнал экспериментальной и теоретической физики, 169, № 2, с. 205-211 (2026)

We study the possibility of registering high-energy extensive air showers (EAS) by the onshore detector facility simultaneously with the trigger of the Baikal-GVD neutrino telescope. The location of the surface detector array on the shore of Lake Baikal is motivated by the fact that permanent placement of detectors on the surface of the lake is challenging. Within the given geometry, simultaneous registration is possible for EAS with a zenith angle of about 76 degrees within the limited solid angle. The corresponding inclined EAS are dominated by muons and significantly attenuated. The installation will make it possible to obtain an estimate of the number of high-energy muons in EAS. This, subsequently, would make it possible to verify EAS modeling and calculations of the atmospheric neutrino flux. The detector may also be used for cross-calibration of energy and direction measurements by the neutrino telescope. We use the CORSIKA program to simulate the registration of EAS on the shore close to the Baikal-GVD. The propagation of ultra-high energy muons produced by EAS through 3.5 km of water and their registration by Baikal-GVD is simulated using the PROPOSAL package. We calculate the minimal total area of the onshore detectors suitable for several cosmic ray energy thresholds, starting from 1 PeV. The report presents estimates of the number of events jointly registered by the onshore installation and the Baikal-GVD the EAS registration detector systems with different areas. Keywords: ultra-high-energy cosmic rays, extensive air showers, Baikal-GVD, Baikal-Top, muon puzzle, high energy muons

Kuzmin N.M., Sirotin D.S., Khoperskov A.V. «Efficiency of parallel computations of gravitational forces by treecode method in n-body models» Математическая физика и компьютерное моделирование (до 2017 г. Вестник Волгоградского государственного университета. Серия 1: Математика. Физика), 27, № 4, с. 39-55 (2024)

Modeling of collisionless galactic systems is based on the n-body model, which requires large computational resources due to the long-range nature of gravitational forces. The most common method for calculating gravity is the TreeCode algorithm, which provides a faster calculation of the force compared to the direct summation of contributions from all particles for n-body simulation. An analysis of the computational efficiency is performed for models with the number of particles up to 10⁸. We considered several processors with differentarchitectures in order to determine the performance of parallel simulations based on the OpenMP standard. An analysis of the use of extra threads in addition to physical cores shows an increase in simulation performance only when all logical threads are loaded, which doubles the total number of threads. This gives an increase in the efficiency of parallel computing by 20 percent on average.