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The terahertz (THz) region of the electromagnetic spectrum, spanning from 0.1 to 10 THz, offers unique opportunities for imaging, spectroscopy, and communication applications. However, the potential of THz technologies has been limited by the availability of efficient and versatile THz emitters. Spintronic THz emitters (STEs), leveraging the ultrafast dynamics of electron spins in magnetic materials, have emerged as a promising solution to this challenge. STEs offer significant advantages, including broad bandwidth, high power output, and room-temperature operation, positioning them at the forefront of THz technology development. Despite these advances, understanding the operational principles and improving the performance of STEs remain areas of active research. This review focuses on the theoretical models that describe the behavior of STEs, aiming to provide a comprehensive overview of the underlying physics and suggest directions for future enhancements. Through a detailed examination of these models, the review seeks to clarify the basics of the physics driving STE performance and highlight innovative strategies for their optimization and application expansion.

Summary: Electroactive Polymer (EAP) hydrogels are an active matter material used as actuators in soft robotics. Hydrogels exhibit active matter behavior through a form of memory and can be used to embody memory systems such as automata. This study exploited EAP responses, finding that EAP memory functions could be utilized for automaton and reservoir computing frameworks. Under sequential electrical stimulation, the mechanical responses of EAPs were represented in a probabilistic Moore automaton framework and expanded through shaping the reservoir’s energy landscape. The EAP automaton reservoir’s computational ability was compared with digital computation to assess EAPs as computational resources. We found that the computation in the EAP’s reaction to stimuli can be presented through automaton structures, revealing a potential bridge between EAP’s use as an integrated actuator and controller, i.e., our automaton framework could potentially lead to control systems wherein the computation was embedded into the media dynamical responses.

Summary: Programmable vanadium dioxide (VO2) metasurface is proposed at THz frequencies. The insulating and metallic states of VO2 can be switched via external electrical stimulation, resulting in the dynamical modulation of electromagnetic response. The voltages of different columns of the metasurface can be controlled by the field-programmable gate array, and thus the phase gradients are realized for THz beam steering. In 1-bit coding, we design periodic and nonperiodic 24 × 24 coding sequences, and achieve wide-angle beam scanning with the deflection angles from −60° to +60°. In 2-bit coding, we use two different meta-atoms to design 18 × 18 coding sequences. Compared with 1-bit coding, 2-bit coding has more degree of freedom to control the optical phase, and 3 dB diffraction efficiency is improved by generating a single deflection angle. The proposed programmable metasurfaces provide a promising platform for manipulating electromagnetic wave in 6G wireless communication.

We present a detailed biographical account and analysis of works of Juda Kreisler (1904–1940s?), a theoretical physicist from Lviv. He was born in Tlumach (Ukrainian: Тлумач, Polish: Tłumacz, Yiddish: טאלמיטש ), nowadays a town in Ivano-Frankivsk oblast in the western part of Ukraine. In 1923, Juda Kreisler finished a gymnasium in Stanislaviv and entered the Philosophical Faculty of the University of Lviv (Wydział Filozoficzny Uniwersytetu Jana Kazimierza [UJK] we Lwowie) in order to study physics. In 1932, he was promoted to the doctoral degree in physics under the supervision of Professor Stanisław Loria. For a short period in the 1930s, Juda Kreisler worked at the Department for Theoretical Physics of the University of Lviv, and returned to the University in 1940, after the Soviets had reorganized it upon taking over Lviv in September 1939. His fate remains unknown: he is listed among murdered by Nazis Jewish employees of the University of Lviv in 1941–43. Dr. Kreisler authored four scientific papers and four abstracts of conference presentations delivered at the Congresses of Polish Physicists in 1932–36. There is, however, another field, where he was extremely prolific in the late 1930s. We have discovered 122 of his popular articles in “Chwila” (English: “Moment”), a local daily newspaper published by the Jewish community in Lviv during 1919–39. These articles covered various subjects, that can be tentatively divided into the following major topics: chronicles and personalia; history of science; discoveries, new studies and inventions; the applied value of science (for medicine and economy in particular); interconnection between science and war; organization of scientific life; Hitler’s Germany and the problem of so-called ‘Aryan science’. While various branches of physics formed the largest part within disciplines reflected in Juda Kreisler’s articles, he also discussed biology, chemistry, meteorology, and geology. The latter field is closely related to his professional career at Lviv’s Geophysical Institute of “Pionier”, a joint-stock company for the exploration and exploitation of bituminous materials, where he spent nine months in 1936.

Summary: The designed confocal elliptical core-shell structure can realize the omnidirectional camouflage effect without disturbing temperature and electric potential profiles as the directions of heat flux and electric current change. Based on the anisotropy of the confocal ellipse, the anisotropic effective parameters of the confocal elliptical core-shell structure are derived under different heat flux and electric current launching. Then, the matrix material should be anisotropic as the effective parameters to satisfy the omnidirectional camouflage effect, which is demonstrated numerically. In addition, we present a composite structure to realize the anisotropic matrix. The experimental results show that the camouflage device embedded in the composite structure can eliminate the scattering caused by the elliptical core under different directions of heat flux and electric current, thus achieving the omnidirectional thermal-electric camouflage effect experimentally. The omnidirectional camouflage effect in thermal and electric fields can greatly widen the application fields of this device with anisotropic geometry.

Исследуется подход к формированию универсальных компетенций в курсе «Теоретическая физика. Модуль: Классическая механика» для студентов бакалавриата на примере раздела, связанного с нахождением закона движения тела. Акцент ставится на подходе к решению уравнений Гамильтона как системы дифференциальных уравнений первого порядка. Модуль «Классическая механика» является начальным этапом изучения теоретической физики. В этом разделе рассматриваются различные подходы к исследованию динамики механических систем, такие как Ньютоновская механика, Лагранжева механика и канонический формализм Гамильтона. Эти подходы являются эквивалентными, но формализм Гамильтона имеет ряд преимуществ. Тематика работы актуальна для студентов педагогических вузов, чьи профессиональные задачи предполагают умение осуществлять поиск, критический анализ и синтез информации, применять системный подход для решения поставленных задач (УК-1), обобщать теоретический материал и применять его к конкретным задачам с конкретными методическими целями. Цель разработки – помочь студентам увидеть общее и различное в решении задач, рассматривая предложенные задачи с единой позиции. Методическая задача состоит в формировании компетенций группы УК-1 при решении предлагаемых заданий.

Summary: Alloying is a successful strategy for tuning the phases and properties of two-dimensional (2D) transition metal dichalcogenides (TMDCs). To accelerate the synthesis of TMDC alloys, we present a method for generating temperature-composition equilibrium phase diagrams by combining first-principles total-energy calculations with thermodynamic solution models. This method is applied to three representative 2D TMDC alloys: an isostructural alloy, MoS2(1-x)Te2x, and two heterostructural alloys, Mo1-xWxTe2 and WS2(1-x)Te2x. Using density-functional theory and special quasi-random structures, we show that the mixing enthalpy of these binary alloys can be reliably represented using a sub-regular solution model fitted to the total energies of relatively few compositions. The cubic sub-regular solution model captures 3-body effects that are important in TMDC alloys. By comparing phase diagrams generated with this method to those calculated with previous methods, we demonstrate that this method can be used to rapidly design phase diagrams of TMDC alloys and related 2D materials.

Summary: Past decades have witnessed the emergence and increasing expansion of parity-time (PT)-symmetric systems in diverse physical fields and beyond as they manifest entirely all-real spectra, although being non-Hermitian. Nonlinear waves in low-dimensional PT-symmetric non-Hermitian systems have recently been explored broadly; however, understanding these systems in higher dimensions remains abstruse and has yet to be revealed. We survey, theoretically and numerically, matter-wave nonlinear gap modes of Bose-Einstein condensates with repulsive interparticle interactions in three-dimensional PT optical lattices with emphasis on multidimensional gap solitons and vortices. Utilizing direct perturbed simulations, we address the stability and instability areas of both localized modes in the underlying linear band gap spectra. Our study provides deep and consistent understandings of the formation, structural property, and dynamics of coherent localized matter waves supported by PT optical lattices in multidimensional space, thus opening a way for exploring and stabilizing three-dimensional localized gap modes in non-Hermitian systems

Summary: In nature, many organisms (e.g., chameleons) protect themselves by changing their colors in response to environmental changes. Inspired by these organisms, we present a multi-responsive, flexible, and structurally colored hydrogel film with a one-dimensional (1D) ordered periodic groove structure. The groove structure endows the film with bright, highly angle-dependent structural colors, which can be reversibly tuned by stretching and releasing. In addition, because of the thermosensitive properties of the hydrogel, the film can be switched between colored state and opaque white state with temperature. In addition, the optical state of the film is sensitive to solvent and can be reversibly changed between colored state and transparent state with soaking and evaporation of the solvent. This reversible, multi-responsive, flexible, and structurally colored hydrogel film has great potential to be used in the fields of color display, sensors, anti-counterfeiting, and so on because of its flexible and diverse tuning methods, excellent optical performance, and convenient preparation process.

Summary: The question of whether terahertz (THz) waves can interact with ions in channels of nerve cells and cause a further reaction has attracted much attention. To answer this question, we investigate the spontaneous radiation generated by Ca2+ moving in calcium channels and the effect of THz radiation on the transport of Ca2+ by solving the mathematical physical model through Brownian dynamics (BD) simulations. It is obtained that the moving Ca2+ in a calcium channel can generate electromagnetic radiation, the corresponding spectrum of which is concentrated in the THz range. Meanwhile, both the ion number in the channel and the background temperature are proved to have significant effects on the spontaneous emission spectra. The studies also show that external THz radiation can accelerate Ca2+ transport through the ion channel. These results are expected to provide a theoretical basis for the future treatment of THz waves in the neurological field.

Summary: Poly-α-methylstyrene (PAMS) is considered as the preferred mandrel material, whose degradation is crucial for the fabrication of high-quality inertial confinement fusion (ICF) targets. Herein, we reveal that hydrogen atom transfer (HAT) during PAMS degradation, which is usually attributed to the thermal effect, unexpectedly exhibits a strong high-temperature tunneling effect. Specifically, although the energy barrier of the HAT reaction is only 10−2 magnitude different from depolymerization, the tunneling probability of the former can be 14–32 orders of magnitude greater than that of the latter. Furthermore, chain scission following HAT will lead to a variety of products other than monomers. Our work highlights that quantum tunneling may be an important source of uncertainty in PAMS degradation, which will provide a direction for the further development of key technology of target fabricating in ICF research and even the solution of plastic pollution.

В работе изучаются некоторые аспекты формирования универсальных компетенций в курсе «Теоретическая физика» (модуль «Классическая механика») для бакалавриата педагогических вузов. В качестве примера выбран фрагмент курса, связанный с нахождением закона движения тела. При решении задач активно используются знания из математических курсов. Актуальность темы заключается в том, что курс теоретической физики объединяет дисциплины естественно-научного и математического циклов, поэтому важно суметь в полной мере использовать накопленные знания для подъема на новый, интегральный уровень освоения учебной информации. Новизна подхода состоит в том, что он дает возможность одновременно формировать научное, исследовательское мышление обучающихся; навыки методики преподавания будущими педагогами физико-математических дисциплин; развивать творческий потенциал обучающихся. Показано, как при решении выбранных задач у студентов формируется набор группы УК-1.

Рассматриваются некоторые аспекты методики преподавания курса «Теоретическая физика» в педагогических вузах (бакалавриат). Данный курс представляет собой основу теоретической подготовки бакалавра-физика. Вниманию предлагаются методы адаптирования непростого для понимания лекционного материала в одном из важных модулей курса «Квантовая механика» при теоретической подготовке педагогов-физиков. Подобная адаптация является актуальной для студентов педагогических вузов ввиду сложности теоретического материала. Предлагаются для разбора на практическом занятии примеры заданий, направленных на прояснение основных теоретических понятий и закрепление знаний, полученных на лекциях. Изучается применение квантовых операторов для исследования квантовой системы, используется вероятностный подход.

Mainstream physicists do not form a unified group of scientists sharing the same opinions. It is generally known that their opinions on the dispute regarding the very foundations of quantum mechanics between Einstein and Bohr still differ. Many renowned physicists defend Einstein's standpoint. However, the support of Bohr's assertions regarding quantum mechanics by various grant agencies and foundations is also very significant. The present paper compares the two physical theories. In their case, there is basically no correlation with empirical indicators. The paper points out the robustness of the theory of strings and the theory of physical vacuum. Physicists elaborated both of these theories on a theoretical basis and they both have strong mathematical bases. Moreover, the theory of physical vacuum can be described as remarkably mathematically elegant. Despite the fact that neither of the theories has yielded relevant empirical results they continue to benefit from the lavish support they get. Witten's string theory is widely supported by mainstream institutions which provide funding to research. As Peter Woit points out it is due to the fact that the string theory is the only game in town. It was born in western culture and the richest institutions found many excellent mathematical physicists who studied the same field. The theory of physical vacuum is equally far-reaching. Its highly ambitious plan-geometrisation of the field using Einstein's method aims at developing a theory of field which would unify all hitherto physical interactions. Simultaneously, the theory introduces a new type of physical field, the so called primary torsion field, and extends the principle of the relativity theory. The theory, however, presents several erroneous results. Moreover, there are no empirical correlations and it has failed to achieve the success of theoretical predictions of the string theory. On the other hand, it receives almost no financial support from mainstream agencies and the number of scientists dealing with the theory is considerably lower. If this theory received as much financial support and scientific attention as the string theory, it would probably achieve the same empirical results. Financial resources and support from relevant institutions thus play a significant role in scientific research.

From the earlier studies in physical and chemical sciences, it is found that the physico-chemical characteristics of chemical compounds are internally connected with their molecular structures. As a theoretical basis, it provides a new way of thinking by analyzing the molecular structure of the compounds to understand their physical and chemical properties. In our article, we study the physico-chemical properties of certain molecular structures via computing the Ediz eccentric connectivity index from mathematical standpoint. The results we yielded mainly apply to the techniques of distance and degree computation of mathematical derivation, and the conclusions have guiding significance in physical engineering.

The aim of this paper is to present Duhem’s critical view of the dynamical development of mechanics according to two principles of his theory of the development of physics: the continuous and the rational development of physics. These two principles impose a formal conception of physics that aims at demarcating physics from the metaphysical view on the one hand and the pragmatist/conventionalist view on the other hand. Duhem pursues an intermediary conception of physics, a representational system of empirical laws based upon formal principles. This formal conception of physics will adjust to his idea of scientific progress in the form of a sequence of representational systems as structures of increasing comprehensiveness of empirical laws, which leads him to defend a convergent structural realism pointing to an ideal physical theory.

It’s revealed from the earlier researches that many physical-chemical properties depend heavily on the structure of corresponding moleculars. This fact provides us an approach to measure the physical-chemical characteristics of substances and materials. In our article, we report the eccentricity related indices of certain important molecular structures from mathematical standpoint. The eccentricity version indices of nanostar dendrimers are determined and the reverse eccentric connectivity index for V-phenylenic nanotorus is discussed. The conclusions we obtained mainly use the trick of distance computation and mathematical derivation, and the results can be applied in physics engineering.

In quantum mechanics, the theory of quantum transitions is grounded on the convergence of a series of time-dependent perturbation theory. In nuclear and atomic physics, this series converges because the dynamics of quantum transitions (quantum jumps) are absent by definition. In molecular and chemical physics, on the contrary, the dynamics of “quantum” transitions, being determined by the joint motion of a light electron (or electrons) and very heavy nuclei, are present by definition, and the series of time-dependent perturbation theory becomes singular. An exception is the dynamic problem for stationary states in the Born-Oppenheimer adiabatic approximation, when the electronic subsystem turns out to be “off” from the general dynamic process and therefore is not dynamically full-fledged: it only forms an electric potential in which the nuclei oscillate. Removing the aforementioned singularity can be accomplished in two ways. The first method was consisted of introducing an additional postulate in the form of the Franck-Condon principle into molecular quantum mechanics, in which the adiabatic approximation is used. The second method was proposed by the author and consisted of damping the singular dynamics of the joint motion of an electron and nuclei in the intermediate (transient) state of molecular “quantum” transitions by introducing chaos. This chaos arises only during molecular quantum transitions and is called dozy chaos. Formally, the damping is carried out by replacing an infinitely small imaginary addition in the spectral representation of the complete Green's function of the system with its finite quantity. The damping chaos (dozy chaos) leads to the continuity of the energy spectrum in the molecular transient state, which is a sign of classical mechanics. Meanwhile, the initial and final states of the molecule obey quantum mechanics in the adiabatic approximation. Molecular quantum mechanics, which takes into account the chaotic dynamics of the transient state of molecular “quantum” transitions, can be called quantum-classical (dozy-chaos) mechanics. The efficacy of the damping for the aforementioned singularity was previously shown by dozy-chaos mechanics of elementary electron transfers in condensed matter, which is the simplest case of dozy-chaos mechanics, and its applications to a whole number of problems, especially to the optical spectra in polymethine dyes and their aggregates. This paper provides a regular exposition of this dozy-chaos (quantum-classical) mechanics of the elementary electron transfers. The main results of its applications presented in the introduction are also described.

We investigate an extension of the Standard Model with one additional triplet of scalar bosons. Altogether, the model contains four Higgs bosons. We analyze the associated production of the doubly charged scalar with the Standard Model gauge bosons and the remaining Higgs bosons of the model, which are: the light (SM) and heavy neutral scalars and a singly charged scalar. We estimate, in the context of the present (HL–LHC) and future (FCC–hh) hadron colliders, the most promising processes in which a single produced doubly charged Higgs boson is involved.

A quantum theoretical approach, within the adiabatic approximation and taking into account a strong non-adiabatic correction via the resonant exchange between the fast mode excited states of the two moieties of the dimer. The intrinsic anharmonicity of the low-frequency mode through a Morse potential, direct and indirect damping, and a selection rule breaking mechanism for forbidden transitions, is applied to reproduce the υX-H IR line shape of cyclic dimers of moderately H-bonded species in the crystalline phase. The results are used to gain an insight into the experimental spectral line shapes obtained by the transmission method. This approach fits satisfactorily the experimental line shape of 2-thiopheneacetic acid and predicts their evolution with isotopic substitution. Numerical calculations show that mixing of all these effects allows one to reproduce the main features of the experimental IR line shapes.

A new and universal theoretical approach to the dynamics of the transient state in elementary physico-chemical processes, called dozy-chaos mechanics (Egorov, V.V. Heliyon Physics2019, 5, e02579), is introduced to a wide general readership.

I develop a framework for interpreting the forces that act on any population described by frequencies. The conservation of total frequency, or total probability, shapes the characteristics of force. I begin with Fisher’s fundamental theorem of natural selection. That theorem partitions the total evolutionary change of a population into two components. The first component is the partial change caused by the direct force of natural selection, holding constant all aspects of the environment. The second component is the partial change caused by the changing environment. I demonstrate that Fisher’s partition of total change into the direct force of selection and the forces from the changing environmental frame of reference is identical to d’Alembert’s principle of mechanics, which separates the work done by the direct forces from the work done by the inertial forces associated with the changing frame of reference. In d’Alembert’s principle, there exist inertial forces from a change in the frame of reference that exactly balance the direct forces. I show that the conservation of total probability strongly shapes the form of the balance between the direct and inertial forces. I then use the strong results for conserved probability to obtain general results for the change in any system quantity, such as biological fitness or energy. Those general results derive from simple coordinate changes between frequencies and system quantities. Ultimately, d’Alembert’s separation of direct and inertial forces provides deep conceptual insight into the interpretation of forces and the unification of disparate fields of study.

In this paper, beyond standard models are considered with additional scalar triplets without modification of the gauge group (Higgs Triplet Model—HTM) and with an extended gauge group S U ( 2 ) R ⊗ S U ( 2 ) L ⊗ U ( 1 ) (Left−Right Symmetric Model—LRSM). These models differ drastically in possible triplet vacuum expectation values (VEV). Within the HTM, we needed to keep the triplet VEV at most within the range of GeV to keep the electroweak ρ parameter strictly close to 1, down to electronvolts due to the low energy constraints on lepton flavor-violating processes and neutrino oscillation parameters. For LRSM, the scale connected with the S U ( 2 ) R triplet is relevant, and to provide proper masses of non-standard gauge bosons, VEV should at least be at the TeV level. Both models predict the existence of doubly charged scalar particles. In this paper, their production in the e + e − collider is examined for making a distinction in the s- and t- channels between the two models in scenarios when masses of doubly charged scalars are the same.

The article reveals advantages of the process of self-study with use of computer didactic means, distinguishes didactic facilities of computer educational programs as to modeling of physical processes on the example of tasks in electrodynamics for self study of students with applying of the program «Component». It is offered examples of tasks for self study in electrodynamics for students with applying of the program «Component».

We give a overview of the main areas in theoretical physics, with emphasis on their relation to Lagrangian formalism in classical mechanics. This review covers classical mechanics; the road from classical mechanics to Schrödinger’s quantum mechanics; electromagnetism, special and general relativity, and (very briefly) gauge field theory and the Higgs mechanism. We shun mathematical rigor in favor of a straightforward presentation.