Theoretical Physics Research Articles

EDITORIAL FOREWORD

New Trends in High-Energy Physics is a series of conferences initiated by the Bogolyubov Institute for Theoretical Physics, National Academy of Sciences of Ukraine in 1992. It is focused on topical problems in experiment, phenomenology and theory of particle, nuclear and astroparticle physics. The conferences were held yearly or biannually at various sites in Ukraine and abroad, namely in Kyiv, Alushta, Yalta, Novy Svit, Odesa (Ukraine), Sukhumi (Georgia), Budva/Beˇci´ci (Montenegro), and Natal (Brazil).

Overcomplete intermediate representation of two-particle Green's functions and its relation to partial spectral functions

Two-particle response functions are a centerpiece of both experimental and theoretical quantum many-body physics. Yet, due to their size and discontinuity structure, they are challenging to handle numerically. Recently, two advances were made to tackle this problem: first, the overcomplete intermediate representation (OIR), which provides a highly efficient compression of Green's functions in imaginary frequency, and second, partial spectral functions (PSFs), which allow for an efficient evaluation in real frequency. We show that there is a two-to-one correspondence between PSFs and OIR coefficients and exploit this fact to construct the OIR for three-or-more-particle propagators. We then use OIR to fit and compress imaginary-frequency data obtained from the numerical renormalization group (NRG), reaching a compression ratio of more than 400. Finally, we attempt to match the OIR data to partial Green's functions from NRG. Due to the overcompleteness, we achieve only qualitative agreement. Published by the American Physical Society 2024

A new search for the variation of fundamental constants using the rovibrational levels and isotope effects of magnesium fluoride molecule

Abstract The recently demonstrated methods for cooling and trapping diatomic molecules offer new possibilities for precision searches in fundamental physical theories. Here, we propose to study the variations of the fine-structure constant (α=e 2/ħc) and the proton-to-electron mass ratio (μ = mp/me) with time - by taking advantage of the nearly degenerate rovibrational levels in the electronic states of the magnesium fluoride (MgF) molecule. Specifically, due to the cancellation between the fine structure splitting and the rovibrational intervals in the different MgF natural isotopes, a degeneracy occurs for the A 2Π(3/2) (v'=0,J'=18.5,-) and the A2Π(1/2) (v''=0,J''=20.5,-). We find that using the nearly degenerate energy level of such states can be 104 times more sensitive than using a pure rotational transition to measure the variations of α and μ. To quantify the small gap between the A2Π(3/2) (v'=0,J'=18.5,-) and the A2Π(1/2) (v''=0,J''=20.5,-), the special transitions of choice are feasible: the X 2Σ(1/2) + (v=0,J=19.5,+) to the A2Π(3/2) (v'=0,J'=18.5,-) and the X 2Σ(1/2) + (v=0,J=19.5,+) to the A 2Π(1/2) (v''=0,J''=20.5,-). In addition, we estimate the frequency uncertainties caused by the narrow linewidth, Zeeman shift, the Stark shift, Doppler boarding and the Blackbody radiation.

Defect quantification evaluation of a rolling element bearing based on physical modelling and instantaneous vibration energy investigation

The estimation of defect size of rolling element bearing (REB) is expected to remain a significant and challenging task in vibration-based condition monitoring of rotating machinery. The conventional approaches focus on extracting the time spacing of the double impulse signal to estimate the defect size of the REB which is subsequently found to be inaccurate and arbitrary. In this paper, a novel model is developed to estimate the defect size of the REB based on the theories of physics and kinematics, in which the multi-event excitations, i.e. the entry, destressing and collision generated by the rolling element-defect interaction, are considered and investigated. The kinematic and geometric contact mechanism, which is mapped onto the rolling element-defect interaction as the rolling element passes over the defect zone, are analyzed and modelled as a function of the time information. In view of the fact that the variation of the vibration energy contained in the multi-impact vibration response is deeply mapped to the time information, a novel idea is proposed to extract the time information by analyzing the instantaneous energy variation of the defect-induced impulse using the scheme of the autoregressive model and the smooth pseudo Wigner-Ville distribution. The proposed model and idea are validated by experiments under different defect size and rotational speed scenarios. The results calculated by the proposed model show good agreement with the real defect size. Experimental and modelling comparisons show that the proposed model has reliable effectiveness and good performance and confidence in quantifying the size of the defect area localized on the outer raceway of the REB, and can provide some theoretical guidance for damage detection and remaining useful life prediction of the REB.

Dynamical Equation Of Cosmology

The general theory of relativity's outcome, the Friedmann equation, captures the universe's dynamics in cosmological terms. This equation provides a geometrical description of the expansion of the cosmos based on the concepts of field theory. The Friedmann equation states that the vacuum energy density, the curvature of space, the density of matter and energy, and the cosmological constant all have an effect on the Hubble parameter, which represents the rate of expansion of the universe. The outcome of the universe's expansion, standstill, or contraction, as shown by this equation, is highly dependent on these factors. Here we have a direct connection between theoretical physics and observable cosmological phenomena like galaxy redshifts and the cosmic microwave background, made possible by the simplification of complex relativistic equations to this form by representing the universe abstractly as a homogeneous and isotropic entity. We may grasp the history, present, and possible future of the universe within a quantitative scientific framework, and the Friedmann equation emphasizes the interaction of matter, energy, and geometry in cosmic development

Extended uncertainty principle and equation of state for dark energy

The modification of Heisenberg's uncertainty principle (HUP), is considered valuable in modern theoretical physics due to its implications on quantum gravity effects. In this paper, we attempted to derive an equation of state for dark energy, using the extended uncertainty principle (EUP) which includes a defined maximum length. We then compared this novel equation with the equations of state obtained from cosmological observations. The observational constraints on dark energy equation of states and the second law of thermodynamics suggest that the EUP parameter sign with maximum length must change.

Theoretical modeling of experimental isotherms for hydrogen storage in La0.9Ce0.1Ni5 alloy

This research reports the results of an experimental and numerical analysis of the La0.9Ce0.1Ni5 alloy's hydrogen absorption and desorption isotherms at three distinct temperatures (T = 313 K, 333 K, and 353 K). We first determined the morphological and structural properties, as well as the hydrogen storage isotherms, of the intermetallic La0.9Ce0.1Ni5 experimentally. The experimental isotherms were then compared to a mathematical model based on statistical physical theory. Due to the good agreement between the experimental isotherms and the proposed model, the insertion and release of hydrogen atoms (nα, nβ), geometric densities of receptor sites (Nαm, Nβm), and absorption-desorption energies (Pα, Pβ) were determined. Moreover, thermodynamic functions like enthalpy, entropy, Gibbs free energy, and internal energy were calculated using these parameters. The findings demonstrated that the intermetallic compound's CaCu5 structure promotes the formation of stable metal hydrides through attractive interactions, ensuring that hydrogen atoms are securely trapped in the metal lattice, thereby enhancing the material's hydrogen storage capacity.

Possible Superconductivity Transition in Nitrogen-Doped Lutetium Hydride Observed at Megabar Pressure.

The pursuit of room-temperature superconductivity at an accessible synthetic pressure has been a long-held dream for both theoretical and experimental physicists. Recently, a controversial report by Dasenbrock-Gammon et al. claims that the nitrogen-doped lutetium trihydride exhibits room-temperature superconductivity at near-ambient pressure. However, many researchers have failed to independently reproduce these results, which has sparked intense skepticism on this report. In this work, a LuH2±xNy sample is fabricated using high-pressure and high-temperature methods. The composition and structural characterization are the same as the aforementioned near-ambient superconductor. In situ X-ray diffraction investigations indicate that a high-pressure phase transition toward Fm m-LuH3±xNy occurred in the sample at 59GPa. The temperature-dependent resistance measurements reveal that two possible superconductivity transition are observed at 95GPa, with Tc1 ≈6.5 K for high-Tc phase and Tc2 ≈2.1 K for low-Tc phase, arising from the disparate phases in the sample. Resistivity measurements in the Fm m-LuH3±xNy phase under varying magnetic fields exhibited characteristics consistent with superconductivity, with an upper critical field μ0Hc2(0) of 3.3 T measured at 163GPa. This work is expected to shed some light on the controversy surrounding superconductivity in the nitrogen-doped lutetium hydride system.

Analyzing lump-type solutions in scalar field models through configurational information measure

In this paper we employ a configurational information measure, specifically the differential configurational complexity (DCC), to quantify the information content of lump-type solutions in various scalar field models, including two modified inverted ϕ4 models, the modified ϕ3 model, as well as two additional families of lump models. Our objective is to complement previous studies by providing an informational perspective that distinguishes different solutions based on their energy configurations. We explore how the DCC measure relates to energy and its applicability in analyzing degenerate states. Our findings indicate that DCC effectively correlates with the energy parameters of the solutions, offering significant insights into their informational properties. This study underscores the value of using informational metrics like DCC to deepen our understanding of the structural and dynamic characteristics of complex systems in theoretical physics.

Eliot’s Scientific Modernism: Newton, Einstein, and Adam Bede

Abstract This exploratory article argues that Eliot uses figurative language to embody her knowledge of theoretical physics by poetically infusing plot structure with moral meaning in Adam Bede, which contains a unified vision of characters, societal milieu, and astrophysical environment. The article’s interpretive analysis demonstrates the influence of Newton’s and, by implication, Einstein’s theoretical physics in Adam Bede’s text, which links characters to their natural environment, analogically identifying them with sun, moon, and Earth. Adam Bede’s key chapters highlight metaphorical solar-lunar imagery inspired by Newton’s laws of motion in the solar system, and amenable to comparisons with Einstein’s empirical photoelectric effect and relativity theory. Blinded by ignorance and arrogance, lunar Hetty and solar Arthur fall into a prolonged collision that violates societal norms personified in earthy Adam. The feminist social conscience of Eliot outpaces Lewes, who advised her to relegate sexually exploited Hetty to a short story, urging her to make mercurial evangelistic Dinah the novel’s female protagonist. Commensurate with Adam Bede’s analogical Newtonian character depiction, Eliot shows narratological inventiveness consistent with her knowledge of mathematics and hard sciences, amalgamating omniscient Newtonian narration interspersed with Einsteinian terse asides, indirect discourse, and avant-garde stream-of-consciousness technique.

The analytical resolution of Klein–Gordon equation with vector and scalar for Coulomb plus Yukawa potentials

Similar to how general relativity emerged, quantum mechanics resulted from experimental observations that made us radically rethink our previous assumptions. Scientists who study atoms need to solve these three equations. They are for a system with N electrons affected by the nucleus’s attractive Coulomb force and the repulsive force between each pair of electrons and other potentials. While general relativity has upended our large-scale conception of the universe, quantum mechanics calls into question all our intuition regarding particle physics. The Klein–Gordon (KG) resolution helps determine some physical systems and their properties by finding their bound states and eigenfunctions. These are resolved using analytical and numerical methods, as well as Coulomb and Yukawa potentials. In order to extract some of the first eigenvalues of the quantum mechanical system, we applied the Nikiforov–Uvarov (NU) method to the KGequation. The findings are significant for understanding nuclear charge radius, spin, nuclear diffusion and other topics in numerous theoretical physics and quantum chemistry fields because they are more generic and helpful.

Dynamical structures of optical solitons for highly dispersive perturbed NLSE with $$\beta $$-fractional derivatives and a sextic power-law refractive index using a novel approach

Dynamical structures of optical solitons for highly dispersive perturbed NLSE with $$\beta $$-fractional derivatives and a sextic power-law refractive index using a novel approach

Blood osmolytes such as sugar can drive brain fluid flows in a poroelastic model

The glymphatic system of fluid flow through brain tissue may clear amyloid-β during sleep and as such underlie the need for sleep. Dysfunctional glymphatic transport has been implicated in pathological conditions ranging from stroke and dementia to psychiatric illnesses. To date, the fastest observed in-vivo brain flows have been reported after the manipulation of blood osmotic pressures. Surprisingly, the brain seems to shrink while receiving more influx. Though influx of an incompressible fluid might expand the tissue, no physical theory for these observations has been proposed. We here present a minimal mathematical model of brain pressure, deformation, and fluid flows due to vascular osmotic pressures. The model is based on Darcy flow, linear poroelasticity theory and conservation of mass. We propose that a screened Poisson equation holds for interstitial pressure because vascular filtration corresponds to fluid divergence. The model resolves the apparent paradox of combined fluid influx with tissue shrinkage by showing that fluid absorption into the blood can drive both. In this model, small glucose concentration differences between plasma and brain can drive brain flow velocities observed in recent in-vivo assays. Osmosis may therefore drive brain fluid flow under physiological conditions and provide an explanation for the known correlations between diabetes and dementia.

Modern Physics and Hyperrealism-antirealism Tendency

This paper delves into the philosophical implications of modern physics, particularly theoretical physics, and its tendency towards hyperrealism-antirealism. Inspired by Baudrillard's concept of hyperreality, we argue that certain aspects of contemporary physics, such as the interpretation of quantum mechanics and the pursuit of theories of everything, exhibit characteristics of a hyperreal state. This hyperreal state is characterized by the detachment from reality, the dominance of simulation over the real, and the loss of a clear distinction between the real and the imaginary. We explore how this trend has led to a departure from a balanced realist perspective, hindering the pursuit of a complete and coherent understanding of the physical world.

High-precision digital rock construction and electrical property upscaling in tight sandstone

The lithology and rock physical properties of tight sandstone reservoirs become increasingly complex, resulting in a more challenging reservoir evaluation process. Conventional rock physics experiments are too restrictive to adequately investigate formation properties. The emerging digital rock physics (DRP) technology in recent years effectively overcomes these constraints. Nevertheless, the current DRP faces two major challenges: the integration of multiple-resolution images and the upscaling of rock physics properties (electricity). In this paper, we propose an innovative method for assigning electrical characteristics to voxel units, enabling the integration of multi-resolution images, as well as a novel approach for establishing a new saturation model to achieve electrical property upscaling. Initially, core samples are selected and drilled based on logging data and lithology analysis, followed by multi-resolution scanning experiments, including X-ray CT, QEMSCAN, and MAPS. After that, mineral components are segmented, and multi-component digital rocks are constructed. Considering mineral voxel as the analytical units, pore characteristics within each mineral, which are extracted from MAPS, are used to generate 3-D pores by QSGS method. These generated 3-D pores are then merged with their respective mineral voxel. Subsequently, the electrical properties of the merged models are simulated and assigned to multi-component digital rock. This process enables the integration of multi-resolution images, leading to the construction of high-precision digital rocks. Additionally, high-precision digital rock-based electrical modeling is conducted, and a new saturation model is then established by combining digital rock physics, experiment rock physics, and theoretical rock physics. Finally, the new saturation model is applied to calculate saturation, accomplishing electrical property upscaling. Application results show the new saturation model improves the accuracy of saturation evaluation, demonstrating the feasibility of the upscaling method for electrical properties.

Universal Energy Fluctuations in Inelastic Scattering Processes.

Quantum scattering is used ubiquitously in both experimental and theoretical physics across a wide range of disciplines, from high-energy physics to mesoscopic physics. In this Letter, we uncover universal relations for the energy fluctuations of a quantum system scattering inelastically with a particle at arbitrary kinetic energies. In particular, we prove a fluctuation relation describing an asymmetry between energy absorbing and releasing processes which relies on the nonunital nature of the underlying quantum map. This allows us to derive a bound on the average energy exchanged. We find that energy releasing processes are dominant when the kinetic energy of the particle is comparable to the system energies, but are forbidden at very high kinetic energies where well-known fluctuation relations are recovered. Our Letter provides a unified view of energy fluctuations when the source driving the system is not macroscopic but rather an auxiliary quantum particle in a scattering process.

Unravelling the Holomorphic Twist: Central Charges

The holomorphic twist provides a powerful framework to study minimally protected sectors in supersymmetric quantum field theories. We investigate the algebraic structure underlying the holomorphic twist of N=1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\mathcal {N}=1$$\\end{document} superconformal field theories in four dimensions. In particular, in holomorphically twisted theories the flavour and conformal symmetry algebras are enhanced to infinite-dimensional higher Kac Moody and higher Virasoro symmetry algebras respectively. We explicitly compute the binary and ternary λ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\lambda $$\\end{document}-brackets and clarify their relation with the underlying infinite-dimensional symmetry algebra. Doing so we show that the central extensions of said symmetry algebras precisely encode the conformal anomalies a and c as well as the flavour central charges of the physical four-dimensional theory. This parallels the familiar story in two dimensions where the conformal anomaly c is encoded in the central extension of the Virasoro algebra.

Momentum – the Archilles’ Heel of Causality-based Physics

Galileo famously discovered the inverse square law of gravitation on earth and also formulated the concept of momentum as “mv” (mass x velocity) for the dynamics of moving bodies. But the momentum “mv” was at an odd with his inverse square law of “Fee Fall” as pointed out later by G.W. Leibniz, who gave the correct formulation of momentum as “mv^2”. G.W.F. Hegel later showed that the momentum expressed as “mv” is incompatible with what he called, “the laws of absolutely free motion” discovered by Kepler’s three laws of the planetary system. However, in spite of the controversy raised by J. Kepler, Leibniz and Hegel; the continued use of “mv” as the measure of momentum of moving bodies in physics and dynamics since R. Descartes and I. Newton; until now, even after the recognition of the quantum phenomena at the turn of the 20th century; is leading to more and more mysteries and myths; impeding further developments in physics and cosmology. It can now be shown that developments in Quantum electrodynamics and dialectics abolishes any notion of Newtonian mystery of “First Impulse” for matter and motion (momentum) from God. Leibniz’s formulation of momentum as “mv^2” is more appropriate and its use can resolve many of the problems in modern theoretical physics and cosmology; including in extra-terrestrial dynamics of the heavenly bodies and gravitation, electrodynamics and in quantum electrodynamics. The recognition of Leibniz’s vis viva, Hegel’s “absolute dynamics” and momentum as “mv^2” (“mv^3” only for neutral quantum particles like light photons); would represent the end of all mysticism and myths of cosmology, created since Isaac Newton’s “negation” of the Copernican revolution; later reinforced and accentuated by Albert Einstein’s theories of relativity.

Surface Plasmons in Two-Dimensional MXenes.

MXenes, a class of layered two-dimensional transition metal carbides and nitrides, exhibit excellent optoelectronic properties and show promise for fields ranging from photonics and communications to energy storage and catalysis. Some members of the MXene family are metallic and exhibit large in-plane conductivity, making them possibly suited for 2D plasmonics. The highly variable chemical structure of MXenes offers a broad chemical space to tune material properties for plasmonic applications, including plasmon-enhanced catalysis, surface-enhanced Raman spectroscopy (SERS), and electromagnetic shielding. However, this synthetic complexity has also presented several roadblocks in the process of moving MXene plasmonics into applications. For example, in the prototypical MXene Ti3C2Tx, there remains disagreement over the bulk plasmon energy and the assignment of a prominent resonance around 1.7 eV. We discuss fundamental models and theories of plasmon physics and apply these models to MXenes in order to clarify some of these problems. We outline the potential for hyperbolic plasmons in MXenes and propose new avenues for MXene photonics research.

T-dualities in gauged linear sigma models

In this paper, we describe non-Abelian T-dualities for a two-dimensional (2D) gauged linear sigma model (GLSM) with [Formula: see text] supersymmetry (SUSY). We start with the case of left and right SUSY [Formula: see text], [Formula: see text] gauge group, and global non-Abelian symmetries. Our analysis applies to the specialization of the GLSM with the global group [Formula: see text], whose original model is the resolved conifold. We analyze the dual model and compute the periods on the dual geometry, matching the effective potential for the [Formula: see text] gauge field, and discussing the coincident singularity at the conifold point. We further present the non-Abelian T-dualization of models with [Formula: see text] SUSY, analyzing the case of global symmetry [Formula: see text]. In this case, the full non-Abelian duality can be solved. The dual geometries with and without nonperturbative corrections to the superpotential coincide. The structure of the dual nonperturbative corrections is determined based on symmetry arguments. The non-Abelian T-dualities reviewed here lead to potential new symmetries between physical theories.