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ВЛИЯНИЕ РАЗРЫВОВ ЦЕПОЧКИ НА ТЕПЛОЕМКОСТЬ ХАЛДЕЙНОВСКОЙ СИСТЕМЫ
Доклады Академии наук высшей школы Российской Федерации. 2017. № 1 (34). С. 19–30.
Popova E., Никифоров А. В.
Disordered ground state with a gap in the spectrum of the magnetic excitation spectrum is realized in the compounds that contain the chains of the magnetic ions with S = 1 spins (Haldane chains). In framework of VBS model, each S = 1 spin can be represented as two pseudo-particle with S = 1/2 spins connected by antiferromagnetic interaction with the pseudo-particle in a neighboring ion. Nonmagnetic impurities within the chain can lead to the formation of the chain segments, and unpaired S = 1/2 spins appear at each end of the chain segments.
In this paper, the influence of the interaction of S=1/2 spins appearing at the ends of the segments of the Haldane chain on the temperature dependence of the specific heat C(T) is studied. The interaction of the end S = 1/2 spins leads to a splitting of the four-fold degenerated ground state of the chain segment into the singlet and the triplet states separated by a gap.The temperature-driven repopulation of the ground state sublevels causes the Schottky anomaly in the C (T) dependence. Using the energy spectrum of the chain segment, which is obtained by taking into account the single-ion anisotropy, we obtain an expression for the specific heat. The analysis shows that in the absence of an external magnetic field, when one of the parameters or is fixed the specific heat peak shifts to higher temperatures with increasing another parameter. For the case of the singlet ground state, the maximum of the specific heat shifts to higher temperatures with increasing magnetic field H. If the ground state is triplet, maximum shifts to lower temperatures at H<3T, and it shifts to higher temperatures at H>7T. In the intermediate field range, the C (T) dependence is more complex. The calculation results are compared with experimental data for compounds Gd2BaNiO5 and (Y1-xNdx)2BaNiO5 published previously.
Publication based on the results of:
Ratnikov F., Bocharnikov V., Journal of High Energy Physics 2026 Vol. 2026 P. 1–21
The BM@N experiment (Baryonic Matter at the Nuclotron) is the first fixed-target experiment at the JINR NICA accelerator complex. In this work, data on the interactions of a carbon-ion beam with kinetic energies of 4.0A GeV and 4.5A GeV with C, Al, Cu, and Pb targets are used to measure transverse momentum spectra and rapidity ...
Added: August 12, 2026
Budkov Y., Kalikin N., Journal of Chemical Physics 2026 Vol. 165 Article 064506
A self-consistent statistical-mechanical theory of the Hall effect in electrolyte solutions is developed by extending the self-consistent Debye–Hückel–Onsager (SCDHO) framework to crossed electric and magnetic fields. The theory incorporates non-local ionic charge distributions via Slater-type form factors, regularizing the Coulomb interaction at short range, and accounts for dielectric friction through ion-specific coefficients, employing experimental values ...
Added: August 12, 2026
Ali S., Bocharnikov V., Ratnikov F. et al., Sensors 2026 Vol. 26 No. 16 Article 5024
Large distributed sensor arrays require repeated recalibration as radiation damage, material aging, gain variation, and readout drift alter channel responses. We studied a high-granularity calorimeter as a large sensor array and addressed unsupervised recalibration from two unpaired datasets: a nominal reference response and an aged response with attenuated cell-wise signals. Aging was modeled by a ...
Added: August 11, 2026
Ponomarev A., Aleksandrov N., Journal of Physics D: Applied Physics 2026 Vol. 59 Article 315205
Electron attachment and detachment in H2O:O2 and H2O:air mixtures are theoretically studied at moderate (40–100 Td) reduced electric fields. It is shown that there are two synergistic mechanisms of ultra-rapid electron detachment from negative ions in these mixtures, whereas these detachment channels are absent in pure gases. Effective attachment coefficient calculated with consideration for fast ion–molecule ...
Added: August 6, 2026
Khrapai V., Tikhonov E., Nature Physics 2026 P. 1–2
Feng et al.1 presented transport measurements of three-terminal normal–superconductor–normal devices based on topological insulator nanowires. They measured the full differential conductance matrix, defined as Gij = ∂Ii /∂Vj , beyond the linear response regime as a function of various control parameters. Here i, j∈ [1, 2] denote normal terminals biased by the voltages V1 and ...
Added: August 5, 2026
G. G. Bondarenko, Kristya V. I., Savichkin D. O. et al., Journal of Surface Investigation: X-Ray, Synchrotron and Neutron Techniques 2026 Vol. 20 No. 2 P. 417–423
A model of a glow gas discharge in a mixture of argon and mercury vapor is formulated in the presence
of a thin insulating film on the cathode surface. Dependences of the discharge characteristics on the
mixture temperature are calculated in the range of its variation, in which a noticeable contribution to ionization
of the working gas is ...
Added: August 1, 2026
Касимов Р. Х., Аржанов А. И., Седых К. О. et al., Оптический журнал 2026 Т. 93 № 1 С. 80–86
Предмет исследования. Использование метода капельного нанесения для изготовления источника одиночных фотонов. Цель работы. Разработка технологического процесса изготовления источника одиночных фотонов на коллоидных квантовых точках для использования их в фотон- ных интегральных схемах. Метод. На первом этапе в программе ANSYS Lumerical рассчитыва- ются период и фактор заполнения фокусирующих элементов связи на длинах волн 545 и 600 ...
Added: July 31, 2026
Nevzorov A., Golikov A., Gneushev D. et al., JETP Letters 2026 Vol. 147–151 No. 3 P. 147–151
This paper demonstrates a special stochastic operation mode of a photonic element with a thin GeTe film deposited at a silicon nitride waveguide. As opposed to traditional deterministic switching between stable states, it has been shown that identical pump laser pulses cause a stochastic change in the transmission coefficient. The discovered effect opens up new ...
Added: July 31, 2026
Dual-mode infrared detection via photovoltaic and barrier pyroelectric effects in PbTe p–n junctions
Jarashneli A., Кобцев Д. М., Upcher A. et al., Journal of Applied Physics 2026 Vol. 140 No. 2 Article 024501
In the work, two effects appeared in PbTe p–n junctions under mid-wavelength infrared (2 − 5 μm) and long-wavelength infrared irradiation (≈10.6 μm). The first effect was created by the optical absorption of lR-photons in PbTe and caused by its photovoltage effect. The second novel effect is related to the heating process and the formation ...
Added: July 31, 2026
Nikolaev G. A., Orlov O. V., Andreeva S. et al., Physical Review Applied 2026 Vol. 26 Article 014099
We report the electrical detection of the spin resonance with temporal resolution in a two-dimensional electron system. Spin resonance was excited by pulses of subterahertz radiation characterized by relatively short rise and fall times on the order of 10 ns and was observed as a resonant peak in the high-frequency conductivity of the two-dimensional channel. The ...
Added: July 31, 2026
S. A. Andreeva, Orlov O. V., A. V. Shchepetilnikov et al., Physical Review B: Condensed Matter and Materials Physics 2026 Vol. 114 No. 6 Article 065420
We investigate the temperature dependence of the pseudospin phase transition at filling factor 𝜈=2 in the quantum Hall regime. Experiments were performed on a high-quality, wide AlAs quantum well, where the pseudospin degree of freedom arises naturally from the near degeneracy and equivalence of the two conduction-band valleys. The anisotropic 𝑔-factor inherent to AlAs enabled independent measurement of ...
Added: July 31, 2026
Metlov K., Andrei B. Bogatyrëv, Annalen der Physik 2026 Vol. 538 No. 6 Article e70234
Thanks to the recent progress in bulk full three-dimensional nanoscale magnetization distribution imaging, there is a growing
interest to three-dimensional (3D) magnetization textures, promising new high information density spintronic applications.
Compared to 1D domain walls or 2D magnetic vortices/skyrmions, they are a much harder challenge to represent, analyze and
reason about. Here we build analytical representation for such ...
Added: July 28, 2026
Dmitry Vasilyev, Gorev V., Ikhsanov R. et al., Journal of Materials Science 2026 No. 61 P. 25452–25470
The orthorhombic phase of 𝛼-Mo2 C is a key component in electrocatalytic applications, as Mo2C-based catalysts can exhibit catalytic performance comparable to or exceeding that of noble metals. Despite its technological relevance, theoretical understanding of the anisotropy in the thermal expansion and related thermoelastic properties of 𝛼-Mo2 C remains limited. In this work, first-principles calculations ...
Added: July 23, 2026
Borovitskaya I. V., Pimenov V. N., Korshunov S. N. et al., Physics of Atomic Nuclei 2026 Vol. 89 No. 1 P. S48–S55
The effect of high-power pulsed laser radiation (LR) generated in the GOS 1001 setup in the
Q-modulated mode (with a flux power density q equal to 1 × 1014 W/m2, pulse duration t = 50 ns, and the
number of pulses N from 1 to 8 in vacuum) on the structure and microhardness of the surface of ...
Added: July 22, 2026
Korogod D., Shapeev A., Ivan S. Novikov, Physical Review B: Condensed Matter and Materials Physics 2026 Vol. 114 No. 2 Article 024104
We present two models with explicit long-range electrostatics in the form of Coulomb interactions. Both models include point charges depending on their local atomic environments, and the second model also conserves a total charge of an atomic system. We combine the proposed long-range models with the local moment tensor potential (MTP) and demonstrate that they ...
Added: July 22, 2026
Sozykin K., Rybin N., Chertkov A. et al., Physical Review B: Condensed Matter and Materials Physics 2026 Vol. 113 No. 22 Article 224111
The global optimization of atomic clusters represents a fundamental challenge in computational chemistry and materials science due to the exponential growth of local minima with system size (i.e., the curse of dimensionality). We introduce a framework that overcomes this limitation by exploiting the low-rank structure of potential energy surfaces through tensor train (TT) decomposition. Our ...
Added: July 22, 2026
Loubenets E. R., / Series arxiv.org "quant-ph". 2026. No. 2607.18050.
In many quantum applications it is important to know whether or not a Bell nonlocal two-qudit state exhibits its nonlocality under correlation scenarios with some given numbers S1,S2≥1 of generalized quantum measurements at two sites. In the present article, we find analytically a new general locality condition sufficient for a nonseparable Werner state with a ...
Added: July 21, 2026
Parfenyev V., Physical Review E - Statistical, Nonlinear, and Soft Matter Physics 2026 Vol. 114 No. 1 Article 015104
Zermelo's navigation problem seeks the trajectory of minimal travel time between two points in a fluid flow. We address this problem for an agent -- such as a floating drone or active particle -- that is advected by a two-dimensional flow, self-propels at a fixed speed smaller than or comparable to the characteristic flow velocity, ...
Added: July 17, 2026
Prokofev V., Zabrodin A., Proceedings of the Steklov Institute of Mathematics 2020 Vol. 309 P. 225–239
We consider solutions of the matrix Kadomtsev-Petviashvili (KP) hierarchy that are trigonometric functions of the first hierarchical time t1 = x and establish the correspondence with the spin generalization of the trigonometric Calogero-Moser system at the level of hierarchies. Namely, the evolution of poles xi and matrix residues at the poles aαibβi of the solutions with respect to the kth hierarchical time of the ...
Added: July 14, 2026
Prokofev V., Zabrodin A., Theoretical and Mathematical Physics 2021 Vol. 208 P. 1093–115
We consider solutions of the 2D Toda lattice hierarchy which are elliptic functions of the zeroth time t_0=x. It is known that their poles as functions of t_1 move as particles of the elliptic Ruijsenaars-Schneider model. The goal of this paper is to extend this correspondence to the level of hierarchies. We show that the ...
Added: July 14, 2026
Ruderman M. S., N. S. Petrukhin, Monthly Notices of the Royal Astronomical Society 2026 Vol. 549 No. 4 Article stag783
For the first time we study kink oscillations of braided coronal magnetic loops. We use the simplest model of a braided loop that consists just of two identical curved magnetic tubes. It is assumed that the plasma density is constant inside the tubes, and also in the surrounding plasma. To describe the kink oscillations we ...
Added: July 12, 2026
V.I. Voitovich, I.S. Makhov, Andryushkin V. V. et al., Journal of Luminescence 2026 Vol. 295 Article 121936
We report on a comparative study of the optical and structural properties of short-period superlattices (SPSLs) based on digital ternary InGaAs/InAlAs alloys and their counterparts with quaternary InGaAlAs barriers, both grown on InP substrates and emitting in the 1.3 μm wavelength range. The heterostructures were grown by molecular beam epitaxy and analyzed using photoluminescence spectroscopy ...
Added: July 8, 2026
Babichev A., Bobrov M., Vasil'ev A. et al., Applied Physics Letters 2026 Vol. 128 No. 24 Article 241102
High-quality planar cavities with low-absorption mirrors based on Al0.2Ga0.8As/Al0.9Ga0.1As layers demonstrate continuous wave lasing at a wavelength of 956 nm. At 300 K, the threshold power density and the quality-factor at the threshold are 4.2 kW/cm2 and 6800. Increasing the pump level above two thresholds results in an enlargement in the quality-factor to at least 19 ...
Added: July 8, 2026
Pilé I., Deng Y., Shchur L., Physical Review B: Condensed Matter and Materials Physics 2026 Vol. 114 No. 1 Article 014101
We investigate the spatial overlap of successive spin configurations in Markov chain Monte Carlo simulations using the local Metropolis algorithm and the Swendsen-Wang and Wolff cluster algorithms. We examine the dynamics of these algorithms for models in different universality classes: Ising model, Potts model with three components, and four-state Potts model. The overlap of two ...
Added: July 6, 2026