Recent Contributions to Physics

Quantum-Noise–Induced Limits on Information Density in Confined Solid-State Systems

Montasir Salman — 2026-03-11

The continuous miniaturization of solid-state systems has driven electronic materials into regimes where quantum noise and environmental coupling play a decisive role in determining physical performance. In this work, we develop an open quantum framework to investigate fundamental limits on information density in confined solid-state systems. By explicitly incorporating system environment interactions at the Hamiltonian level and describing the resulting non-unitary dynamics within the Lindblad formalism, we derive an intrinsic upper bound on the number of operationally distinguishable quantum states. Our analysis reveals that information density scaling is jointly constrained by geometric confinement and noise-induced coherence loss, leading to an apparent exponential growth only within an intermediate size regime. As system dimensions approach the nanoscale, increasing quantum noise enforces a crossover to sub-exponential, noise-limited behavior, signaling the breakdown of purely geometric scaling arguments. The results demonstrate that the observed scaling behavior arises as an emergent consequence of open quantum dynamics rather than technological optimization. Owing to its general formulation, the proposed framework is broadly applicable to a wide class of solid-state systems, providing a unified physical perspective on information-density limits imposed by quantum noise.

Interrelation of fusion cross-section, reaction rate, and neutron production in a D-D reaction in a plasma focus device

Zh.M. Moldabekov — 2026-03-11

This study presents analysis of D-D thermonuclear fusion processes occurring in a plasma focus device by examining the interrelation between fusion cross-section, reaction rate, nuclear reaction time and neutron production. The goal of the study is to clarify the mechanisms of neutron production from the viewpoint of nuclear reaction kinetics governed by Coulomb barrier penetration and quantum tunneling effects. The fusion cross-section and reaction rate were calculated for deuteron energies in the range of 1-200 keV and compared with nuclear data libraries EXFOR and ENDF. The neutron particles which produced as a result of the D-D fusion reaction were registered using a silver activation foil detector. The corresponding effective deuterium ion energy region of 25-100 keV for D-D fusion reaction, cross-section 10^-3-10^-2 barn and nuclear reaction time 20-80 ns were found. It is consistent with experimentally observed neutron pulse durations producing during the pinch phase. In this case, the rate of nuclear fusion reactions in deuterium increases by approximately an order of magnitude compared to Maxwellian plasma, while the requirements for the magnetic confinement parameters of such plasma are significantly reduced.

Quasi-periodic oscillations around compact objects within the Sen spacetime

T. Konysbayev — 2026-02-25

We investigate kilohertz (kHz) quasi-periodic oscillations (QPOs) observed in eight neutron-star low-mass X-ray binaries within the framework of the relativistic precession model (RPM). Fundamental (epicyclic) frequencies of test particles on circular orbits are computed in the static Sen spacetime. By fitting the Keplerian and epicyclic frequencies to the observed lower and upper QPO frequency pairs, (f_U, f_L) we infer the masses and electric charges of the compact objects and compare the results with those obtained in the Schwarzschild spacetime using the Akaike and Bayesian information criteria (AIC/BIC). We find that the Schwarzschild geometry provides physically consistent fits for four sources, while for GX 5–1 and GX 340+0 the Sen spacetime becomes effectively indistinguishable from Schwarzschild, indicating that no electric charge is required. Although the Sen metric yields statistically improved fits for the remaining four sources, the inferred large masses as well as large electric charges are incompatible with neutron-star physics. We therefore conclude that the static Sen spacetime does not provide a physically viable description of kHz QPOs in neutron-star systems.

Experience of using an infrared camera in the study of astronomical objects

А.А. Solodovnik — 2026-03-05

Based on the analysis of images of comet C/2023 A3 Tsuchinshan-ATLAS, obtained in both visible light and near-infrared range (wavelength over 850 nm) using CANON EOS 2000D and CANON EOS 1000DI (infrared) cameras, the influence of the observation spectral range on image contrast is studied. The image quality criterion is its contrast. Contrast coefficient calculations were performed using the standard ImageJ program used for image processing and analysis in various scientific applications. Several approaches to determining comet image contrast were used. Comparison of the obtained results did not reveal significant advantages of shooting in the mentioned spectral ranges. However, the analysis of noctilucent cloud images obtained using the same methodology revealed a significant advantage of infrared imaging, which sharply increases image contrast. A detailed analysis of shooting conditions suggested that the reduced effectiveness of infrared imaging is due to the transition from light scattering conditions of the daytime sky to twilight, and then to night conditions. A rationale is proposed for further studying methods of improving imaging efficiency when transitioning from the visible spectrum range to the near-infrared spectrum range.