Formulation Of Theory Research Articles

Formal theory of heavy ion double charge exchange reactions

The theory of heavy ion double charge exchange (DCE) reactions A(Z, N) → A(Z ± 2, N ∓ 2) is recapitulated emphasizing the role of Double Single Charge Exchange (DSCE) and pion-nucleon Majorana DCE (MDCE) reactions. DSCE reactions are of second–order distorted wave character, mediated by isovector nucleon-nucleon (NN) interactions. The DSCE response functions resemble the nuclear matrix elements (NME) of 2ν2β decay. The MDCE process proceeds by a dynamically generated effective rank-2 isotensor interaction, defined by off–shell pion–nucleon DCE scattering. In closure approximation pion potentials and two–nucleon correlations are obtained, similar to the neutrino potentials and the intranuclear exchange of Majorana neutrinos in 0ν2β Majorana double beta decay (MDBD).

Ga and In-based hybrid halide perovskites as an alternative to Pb: a first principles study.

Lead-free hybrid halide perovskites have gained much attention in the field of photovoltaics due to their non-toxicity, stability and unique photo-physical properties. Sn and Ge-based ABX3 perovskites have been widely studied due to their similar electronic properties to Pb-based materials. However, the unstable oxidation state of Sn is a major challenge for the commercialization of this class of materials. To overcome this problem, here, we have designed a series of novel Ga and In-based A3B2X9-type perovskite materials incorporating the methylammonium (MA) organic cation in the A site and I- as the halide ion in the X site. In this regard, we have investigated different structural, electronic, optical and photovoltaic properties by employing the density functional theory formalism. The formation of a stable three dimensional perovskite structure is determined by the observed values of tolerance factor (TF) and octahedral factor (μ). The observed negative values of formation enthalpy manifest that our studied materials are also thermodynamically stable. The obtained band gap values reveal that our designed perovskite materials can act as semiconducting materials for application in photovoltaics. We have also investigated the optical properties of our studied materials and the observed values of dielectric function and absorption coefficient in the visible range of the electromagnetic spectrum indicate their excellent photo absorption. The observed theoretical power conversion efficiency (PCE) values reveal that (MA)3In2I9 (13.82%) and (MA)3 (Ga.50In.50)2I9 (12.8%) can be chosen as potential candidates for application in perovskite-based photovoltaics. This research provides a pathway for the development of less toxic and efficient semiconducting materials, offering exciting prospects for their utilization in optoelectronics and contributing to the ongoing efforts to advance sustainable energy technologies.

Local force constants and charges of the nitrosyl ligand in photoinduced NO linkage isomers in a prototypical ruthenium nitrosyl complex.

Photoinduced linkage isomers (PLI) of the NO ligand in transition-metal nitrosyl compounds can be identified by vibrational spectroscopy due to the large shifts of the (NO) stretching vibration. We present a detailed experimental and theoretical study of the prototypical compound K2[RuCl5NO], where (NO) shifts by ≈150 cm-1 when going from the N-bound (κN) ground state (GS) to the oxygen-bound (κO) metastable linkage isomer MS1, and by ≈360 cm-1 when going to the side-on (κ2N,O) metastable linkage isomer MS2. We show that the experimentally observed N-O stretching modes of the GS, MS1, and MS2 exhibit strong coupling with the Ru-N and Ru-O stretching modes, which can be decoupled using the local mode vibrational theory formalism. From the resulting decoupled pure two-atomic harmonic oscillators the local force constants are determined, which all follow the same quadratic behavior on the wavenumber. A Bader charge analysis shows that the total charge on the NO ligand is not correlated to the observed frequency shift of (NO).

Foundations of time-symmetric physics 1. Time-symmetric relativity and relativistic quantum mechanics

Time-symmetric theory (TST) is formulated as a theoretical foundation of time-symmetric physics (TSP), classical, relativistic and quantum. TST is based on the widely used in particle physics fact that the description of positive energy antiparticles moving forward in space and time is equivalent to the description of negative energy particles moving backward in space and time (Zisman 1940, Stückelberg 1941, Feynman 1949). In TST, this fundamental fact is generalized by formulating the equivalence principle of particle physics and applying it to all physical phenomena in the rest frames of negative energy particles. As a result, the group of transformations TST also includes such inertial frames that move backward in space and time with coordinates related to the ordinary ones by 4-inversion. This led to the formulation of time-symmetric relativity theory and corresponding relativistic quantum mechanics. In the latter, the probabilities remain positive, but the bilinear forms of the wave functions are associated with probability currents, the signs of which depend on the direction of movement along the coordinate axes, including the time axis. In TST, therefore, the Klein-Gordon equation is a consistent equation for probability amplitudes, and the fermion theory contains the necessary corrections, which make it physically more consistent, unchanging its main observational consequences. Applications of TST to quantum fields will be considered in the second article.

МОДЕЛИРОВАНИЕ СИСТЕМЫ ЭПИГЕНЕТИЧЕСКОЙ ПАМЯТИ С ТРАНСКРИПЦИОННОЙ РЕПРЕССИЕЙ И МЕТИЛИРОВАНИЕМ ДНК

The in silico model of the epigenetic memory system synthesized in Escherichia coli [Maier et al., 2017, Nat. Comm., 8:15336] was developed. The system includes an artificial memory operon with DNA methyltransferase CcrM from Caulobacter crescentus methylating the promoter of this operon, and an engineered transcriptional repressor gene ZnF that blocks the same promoter in an unmethylated state. The memory operon, which is located on the maintenance plasmid, is controlled by a trigger plasmid carrying a specific arabinose-inducible operon. The artificial trigger operon functions as part of an expanded arabinose regulon. An additional model is used to describe the operation of the latter. The unified model of the memory control system takes into account positive and negative control by the regulatory protein araC, negative feedback self-regulation and negative direct, methylation-sensitive regulation by the ZnF protein, and DNA methylation. The models are built in the language of the formalism of the dynamic theory of molecular genetic control systems. The models were calculated in the SETIES software package to analyze the dynamics of control gene networks, dynamic epigenes and cell ensembles. Computer experiments have shown that the switch has two alternative functional modes, each of which is stable in a series of successive cell divisions. Both modes are characterized in terms of the molecular component dynamics of the artificial memory operon, the trigger operon, and the natural L-arabinose catabolism operon.

Energy Spectra of Nonlocal Internal Gravity Wave Turbulence.

Starting from the classical formulation of the weak turbulence theory in a density stratified fluid, we derive a simplified version of the kinetic equation of internal gravity wave turbulence. This equation allows us to uncover scaling laws for the spatial and temporal energy spectra of internal wave turbulence which are consistent with typical scaling exponents observed in the oceans. The keystone of our description is the assumption that the energy transfers are dominated by a class of nonlocal resonant interactions, known as the "induced diffusion" triads, which conserve the ratio between the wave frequency and vertical wave number. Our analysis remarkably shows that the internal wave turbulence cascade is associated to an apparent constant flux of wave action.

Use of scalar fields in physics and cosmology

In this paper we discuss briefly the use of scalar fields in Physics and in several research areas, such as Condensed Matter and Cosmology. The versatility of the scalar fields has made them prominent in the contemporary scientific scenario, leading them to be used in the formulation of the Higgs field theory, in the theories of cosmic inflation and of dark energy and in the study of topological defects.

A note on the Hamiltonian structure of transgression forms

By incorporating two gauge connections, transgression forms provide a generalization of Chern-Simons actions that are genuinely gauge-invariant on bounded manifolds. In this work, we show that, when defined on a manifold with a boundary, the Hamiltonian formulation of a transgression field theory can be consistently carried out without the need to implement regularizing boundary terms at the level of first-class constraints. By considering boundary variations of the relevant functionals in the Poisson brackets, the surface integral in the very definition of a transgression action can be translated into boundary contributions in the generators of gauge transformations and diffeomorphisms. This prescription systematically leads to the corresponding surface charges of the theory, reducing to the general expression for conserved charges in (higher-dimensional) Chern-Simons theories when one of the gauge connections in the transgression form is set to zero.

Occurrence of catastrophic tool wear patterns through systematic thermomechanical modeling

To achieve optimal tool performance, it is essential to not only comprehend the wear patterns during the steady wear stage but also the final one where catastrophic wear patterns are usually involved. However, previous focus has been put individually into them, thereby the mechanism connections in between have not yet been completely demonstrated. This study aims to bridge this gap by developing an analytical model based on the slip-line theory and imaginary heat source formulations for worn tools with cutting edge geometry extracted from the steady wear stage. The model computes the thermomechanical loads on the tool surface, which are then incorporated into a mechanism-based wear rate model that has been carefully calibrated. Finally, a nodal-displacement algorithm is used to iteratively determine the further tool edge profiles until the final wear stage. The sequential edge profiles demonstrate that the most significant wear increments occur at the rear of the tool flank wear land, resulting in a gradually deepening and widening notched region. These predictions are consistent with experimental findings where a notch belt wear is observed to grow along the tool main cutting edge during the steady wear stage, which ultimately decreases the edge toughness and leads to catastrophic wear patterns.

On Clifford multivector-valued actions, generalized Dirac equation and quantization of branes

We explore the construction of a generalized Dirac equation via the introduction of the notion of Clifford multivector-valued actions, which was inspired by the work of Kanatchikov [Kanatchikov IV. De Donder-Weyl theory and a hypercomplex extension of quantum mechanics to field theory. Rept Math Phys. 1999;43:157–170; Kanatchikov IV. De Donder-Weyl Hamiltonian formulation and precanonical quantization of Vielbein gravity. J Phys Conf Ser. 2013;442:012041] on the De Donder-Weyl formulation of field theory. Crucial in this construction is the evaluation of the exponentials of multivectors associated with Clifford (hypercomplex) analysis. Exact matrix solutions (instead of spinors) of the generalized Dirac equation in D = 2 , 3 space–time dimensions are found. This formalism can be extended to curved space–time backgrounds. We conclude by proposing a wave-functional equation governing the quantum dynamics of branes living in C-spaces (Clifford spaces), and which is based on the De Donder–Weyl Hamiltonian formulation of field theory.

Postawić kwantową teorię pola z głowy na nogi część 2

Despite the impression that can be gained from most of the standard textbooks, Dirac, Klein–Gordon and other wave equations do not constitute the basis of relativistic quantum field theory. In this article I attempt to show how it should be formulated properly and discuss some of its aspects which usually are presented unsatisfactorily. My aim is to cause the change in the way quantum field theory is taught.The text is split into three parts. In the second part I discuss the formulation of quantum field theory as a theory of interacting fields as well as the physical sense of the renormalization procedure.

Meta-Synthesis As an Original Method to Synthesize Qualitative Literature in Chronic Diseases: A Narrative Review

Context: The recent growth of research and the vast amount of knowledge available highlight the necessity for synthesizing existing research in a reliable and high-quality manner. The substantial body of qualitative meta-synthesis studies on chronic diseases indicates the need for a deeper understanding of this methodology. Therefore, the purpose of this paper was to explain the process of meta-synthesis in qualitative research. Methods: This was a narrative review with predefined inclusion and exclusion criteria, followed by a web search using relevant keywords. Initially, 980 relevant articles were selected. Subsequently, the titles, abstracts, and full texts were assessed for eligibility using the Critical Appraisal Skills Program checklist. Finally, 21 articles were included in this study. Results: Various approaches have been adopted to address the meta-synthesis of qualitative studies. Common types of qualitative meta-synthesis include meta-narrative, critical interpretive synthesis, meta-study, meta-ethnography, grounded formal theory, thematic synthesis, textual narrative synthesis, framework synthesis, and ecological triangulation. However, concerning chronic diseases, the most commonly used methods were ethnography and Sandelowski and Barroso’s method. Conclusions: Meta-synthesis is a method for integrating the results of studies, re-understanding the findings, and ultimately interpreting them to generate new insights beyond what is obtained from individual studies. Given the extensive body of qualitative research on chronic diseases, it is recommended to conduct this type of research to develop new knowledge based on the findings of previous studies.

Serce działań publicznych w historycznych miastach: refleksje na temat programu HRIDAY

This article discusses two specific implementations from the Heritage City Development and Augmentation Yojana, also known as the HRIDAY scheme in India, specifically how they address public spaces in historical cities. HRIDAY (2014-2019) was formulated to provide holistic development and improve infrastructure, mainly in pilgrim towns, under the Ministry of Urban Development, now the Ministry of Housing and Urban Affairs (MoHUA). The scheme took into consideration the complexity of dealing with entire historic cities. This is especially challenging for local urban bodies focused primarily on the core of a city, i.e. its historic centre. The goal was to revitalise the city’s unique character by “encouraging the development of an aesthetically appealing, accessible, informative and secure environment” (MOUD 2015). However, while the scheme ended, there are still many historic towns and cities across the country that could benefit from reflections and insights from already executed projects. To undertake any further development in line with the scheme, it is imperative to understand its application, specifically in terms of public space typology. HRIDAY primarily addressed the need to foster cultural identity by improving public infrastructure and promoting tourism. The article addresses how public chowks (squares) and market streets benefited from the scheme, basing on secondary sources about two selected cities. Discussion covers additions of sanitation and public conveniences, development of venues for cultural events in existing public space and interventions such as creation of interpretation centres and improvement of paths. These analyses serve as the basis for the formulation of guidelines and theories that could inform future heritage development in sensitive urban spaces in cities and towns across India.

Photoinduced Electron Transfer in Inclusion Complexes of Carbon Nanohoops.

ConspectusPhotoinduced electron transfer (PET) in carbon materials is a process of great importance in light energy conversion. Carbon materials, such as fullerenes, graphene flakes, carbon nanotubes, and cycloparaphenylenes (CPPs), have unusual electronic properties that make them interesting objects for PET research. These materials can be used as electron-hole transport layers, electrode materials, or passivation additives in photovoltaic devices. Moreover, their appropriate combination opens up new possibilities for constructing photoactive supramolecular systems with efficient charge transfer between the donor and acceptor parts. CPPs build a class of molecules consisting of para-linked phenylene rings. CPPs and their numerous derivatives are appealing building blocks in supramolecular chemistry, acting as suitable concave receptors with strong host-guest interactions for the convex surfaces of fullerenes. Efficient PET in donor-acceptor systems can be observed when charge separation occurs faster than charge recombination. This Account focuses on selected inclusion complexes of carbon nanohoops studied by our group. We modeled charge separation and charge recombination in both previously synthesized and computationally designed complexes to identify how various modifications of host and guest molecules affect the PET efficiency in these systems. A consistent computational protocol we used includes a time-dependent density-functional theory (TD-DFT) formalism with the Tamm-Dancoff approximation (TDA) and CAM-B3LYP functional to carry out excited state calculations and the nonadiabatic electron transfer theory to estimate electron-transfer rates. We show how the photophysical properties of carbon nanohoops can be modified by incorporating additional π-conjugated fragments and antiaromatic units, multiple fluorine substitutions, and extending the overall π-electron system. Incorporating π-conjugated groups or linkers is accompanied by the appearance of new charge transfer states. Perfluorination of the nanohoops radically changes their role in charge separation from an electron donor to an electron acceptor. Vacancy defects in π-extended nanohoops are shown to hinder PET between host and guest molecules, while large fully conjugated π-systems improve the electron-donor properties of nanohoops. We also highlight the role of antiaromatic structural units in tuning the electronic properties of nanohoops. Depending on the aromaticity degree of monomeric units in nanohoops, the direction of electron transfer in their complexes with C60 fullerene can be altered. Nanohoops with aromatic units usually act as electron donors, while those with antiaromatic monomers serve as electron acceptors. Finally, we discuss why charged fullerenes are better electron acceptors than neutral C60 and how the charge location allows for the design of more efficient donor-acceptor systems with an unusual hypsochromic shift of the charge transfer band in polar solvents.

Don’t Look Back in Anger: Cooperation Despite Conflicting Historical Narratives

States in conflict often have divergent interpretations of the past. They blame each other for starting the conflict and view their own actions as justified retaliation, which makes them reluctant to cooperate. This phenomenon, while common in international relations, is not well understood by existing formal theories of cooperation. In the context of the Repeated Prisoner’s Dilemma framework, we show that strategies that demand atonement for past misdeeds are outperformed by strategies that do not. The latter are able to get out of retaliatory cycles and return to cooperation more quickly when there are divergent perceptions of the past. We conclude with a case study of Chinese and U.S. responses to the Tiananmen protests of 1989. China and the United States strongly disagree about the cause of the Tiananmen uprising and the legitimacy of the Chinese response, but nevertheless returned to cooperation after a limited period of mutual punishment.

A THEMATIC AND STRUCTURAL ANALYSIS OF TEKHAYYULĀT: THE PROMINENT PERSIAN POETRY COLLECTION BY NAIM FRASHERI

The spread of Islam in the Balkans under Ottoman rule along with the emergence of Sufi sects, including the Bektashi order, paved the way for the expansion of Persian literature as a source of Sufi literature in this region and especially in Albania. Over the centuries, the Persian language and literature have maintained their presence and function in the Balkans, and several Sufi figures and intellectuals have chosen Persian as the medium for the expression of their literary creations. Among them, The most well-known Albanian who wrote Persian poetry in the late 19th century is undoubtedly Naim Frasheri (1846-1900). He published his collections of Persian poems, entitled “Tekhayyulāt” in 1885 in Istanbul. In this paper, after an overview of the spread and development of the Persian language and literature in the Balkans and in Albania, Naim’s poems in “Tekhayyulāt” are presented and analysed. The study is grounded on the theory of formalism in literature and aims to apply structural analysis to Naim’s Persian poems. To this end, employing a qualitative approach as the research methodology, two types of analyses are conducted, thematic analysis which reviews the content and the themes of his poems, and then structural analysis which is based on Leech’s theory of linguistic deviation (1969), focuses on the application of three types of linguistic deviations, namely phonological, lexical and grammatical, to enable a structural analysis of the poems. The results of the analysis show that Naim’s Persian poems have limited ranges of themes, and the main theme in his poems is about ‘nature’ while the structural analysis of linguistic deviations in his poems indicates his mastery of the Persian language to express his thoughts in poetic form.

Объединение универсальной эпистемологии с формальной аксиологией в мультимодальной формальной аксиоматической теории «сигма + 2c», и философские основания математики (на англ.)

The paper is devoted to investigating Kant’s apriorism underlying Hilbert’s formalism in philosophical foundations of mathematics. The target is constructing a formal axiomatic theory of knowledge in which it is possible to invent formal inferences of formulae-modeling-Hilbert-formalism from the assumption of Kant apriorism concerning mathematics. The scientific novelty: a logically-formalized axiomatic system of universal philosophical epistemology called “Sigma +2C” is invented for the first time as a generalization of the already published formal epistemology system “Sigma +C”. In comparison with “Sigma +C”, a new symbol is included into the object-language-alphabet of S+2C, namely, the symbol standing for the perfection-modality “it is complete that…”. Also, one of axiom-schemes of “Sigma +C” is generalized in “Sigma + 2C”. In “Sigma +2C”, it is proved deductively that under the assumption of a-piori-ness of mathematical knowledge, its completeness and consistency are equivalent.

Dissipative Scattering of Spinning Black Holes at Fourth Post-Minkowskian Order.

We compute the radiation reacted momentum impulse Δp_{i}^{μ}, spin kick ΔS_{i}^{μ}, and scattering angle θ between two scattered spinning massive bodies (black holes or neutron stars) using the N=1 supersymmetric worldline quantum field theory formalism up to fourth post-Minkowskian (4PM) order. Our calculation confirms the state-of-the-art nonspinning results, and extends them to include spin-orbit effects. Advanced multiloop Feynman integral technology including differential equations and the method of regions are applied and extended to deal with the retarded propagators arising in a causal description of the scattering dynamics. From these results we determine a complete set of radiative fluxes at subleading PM order: the 4PM radiated four-momentum and, via linear response, the 3PM radiated angular momentum, both again including spin-orbit effects.

Generalized dualities and supergroups

Using a recently developed formulation of double field theory in superspace, the graviton, B-field, gravitini, dilatini, and Ramond-Ramond bispinor are encoded in a single generalized supervielbein. Duality transformations are encoded as orthosymplectic transformations, extending the bosonic O(D, D) duality group, and these act on all constituents of the supervielbein in an easily computable way. We first review conventional non-abelian T-duality in the Green-Schwarz superstring and describe the dual geometries in the language of double superspace. Since dualities are related to super-Killing vectors, this includes as special cases both abelian and non-abelian fermionic T-duality.We then extend this approach to include Poisson-Lie T-duality and its generalizations, including the generalized coset construction recently discussed in [arXiv:1912.11036]. As an application, we construct the supergeometries associated with the integrable λ and η deformations of the AdS5 × S5 superstring. The deformation parameters λ and η are identified with the possible one-parameter embeddings of the supergravity frame within the doubled supergeometry. In this framework, the Ramond-Ramond bispinors are directly computable purely from the algebraic data of the supergroup.

Computational study of lattice and thermoelectric properties of Rb2LiTlF6 double perovskite

We applied the density functional theory formalism to compute the lattice thermal conductivity, transport and thermoelectric properties of Rb2LiTlF6 double perovskite in the cubic phase. To gain some insights on lattice related dynamic behaviour of this material, we determined its phonon lifetimes and Grüneisen parameters within the considered frequency range. This quaternary compound has a very low value of lattice thermal conductivity, with the predicted value of 0.687 W/mK at 300 K. The highest value of dimensionless figure of merit was determined to be 5.73 × 10−3 at 800 K when hole concentration is 1020 cm−3, this low ZT value could be attributed to the wide band gap nature of this compound. Our results will serve as a benchmark for future experimental and theoretical research on lattice and thermoelectric properties of this material.