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This article provides a detailed exploration of the geography, mining history, and mineralogy of the Elkhorn Mountains in southwestern Montana. It focuses on the Elkhorn and Radersburg mining districts and discusses the specific mines and minerals found in the area. The article also delves into the concept of epitaxy, which involves the growth of crystals on preexisting crystals, and explains the different types of oriented intergrowths. The authors conducted a study on the epitactic relationship between quartz and hemimorphite minerals, observing their structural similarities and suggesting a shared framework as the reason for this relationship. The article concludes with acknowledgments to mine owners and individuals who assisted in the research. [Extracted from the article]

This document explores the concept of Stone-Wales rotations and their application in manipulating the structure of fullerenes. The rotations involve rearranging carbon atoms to create new rings, specifically heptagons. The authors discuss the implications of these rotations in various fields, including chemistry, nanoscience, and mathematical chemistry. They also highlight the potential for studying quantum phenomena and the creation of new molecular structures. The document provides graphical tools and examples to aid in understanding the effects of these rotations on fullerene surfaces. [Extracted from the article]

A new formalism is introduced that makes it possible to elucidate the physical and geometric content of quantum space–time. It is based on the Minimum Group Representation Principle (MGRP). Within this framework, new results for entanglement and geometrical/topological phases are found and implemented in cosmological and black hole space–times. Our main results here are as follows: (i) We find the Berry phases for inflation and for the cosmological perturbations and express them in terms of the observables, such as the spectral scalar and tensor indices, n S and n T , and the tensor-to-scalar ratio r. The Berry phase for de Sitter inflation is imaginary with the sign describing the exponential acceleration. (ii) The pure entangled states in the minimum group (metaplectic) M p (n) representation for quantum de Sitter space–time and black holes are found. (iii) For entanglement, the relation between the Schmidt type representation and the physical states of the M p (n) group is found: This is a new non-diagonal coherent state representation complementary to the known Sudarshan diagonal one. (iv) Mean value generators of M p (2) are related to the adiabatic invariant and topological charge of the space–time, (matrix element of the transition − ∞ < t < ∞ ). (v) The basic even and odd n-sectors of the Hilbert space are intrinsic to the quantum space–time and its discrete levels (in particular, continuum for n → ∞ ), they do not require any extrinsic generation process such as the standard Schrodinger cat states, and are entangled. (vi) The gravity or cosmological domains on one side and another of the Planck scale are entangled. Examples: The quantum primordial trans-Planckian de Sitter vacuum and the classical late de Sitter vacuum today; the central quantum gravity region and the external classical gravity region of black holes. The classical and quantum dual gravity regions of the space–time are entangled. (vii) The general classical-quantum gravity duality is associated with the Metaplectic M p (n) group symmetry which provides the complete full covering of the phase space and of the quantum space–time mapped from it. [ABSTRACT FROM AUTHOR]

This paper presents the efficient reduction of phosphinoylacetic acid esters and 3-phosphorylated coumarin to their corresponding phosphino-boranes using BH₃-THF complexes. Optimized conditions for the reduction of phosphinoylacetic acid esters resulted in high yields of phosphinoborates. The straightforwardness and efficiency of the process were demonstrated for diarylphosphinoylacetic acid ethyl esters, as well as P-stereogenic L-menthyl esters, where the simultaneous reduction of the strong P=O bond and the ester group was exclusively observed for the first time. The study also highlighted the significant influence of steric effects with bulky substituents, such as the menthol group or the 1-naphthyl substituent at phosphorus, on the reduction efficiency. However, the reduction of 3-phosphorylated coumarins produced an unexpected reaction product: a 2,3-dihydrobenzofuran derivative. The present findings provide valuable information on the direct reduction of phosphine oxides and related compounds, demonstrating the versatility of borane complexes in synthetic chemistry, and provide new perspectives for studying the problems of symmetry and asymmetry in the chemistry of such transformations. [ABSTRACT FROM AUTHOR]

This document explores the concept of Stone-Wales rotations and their application in manipulating the structure of fullerenes. The rotations involve rearranging carbon atoms to create new rings, specifically heptagons. The authors discuss the implications of these rotations in various fields, including chemistry, nanoscience, and mathematical chemistry. They also highlight the potential for studying quantum phenomena and the creation of new molecular structures. The document provides graphical tools and examples to aid in understanding the effects of these rotations on fullerene surfaces. [Extracted from the article]

This paper is devoted to some selected topics of the theory of special orthogonal group SO(3). First, we discuss the trace of orthogonal matrices and its relation to the characteristic polynomial; on this basis, the partition of SO(3) formed by conjugation classes is described by trace mapping. Second, we show that every special orthogonal matrix can be expressed as the product of three elementary special orthogonal matrices. Explicit formulas for the decomposition as needed for applications in differential geometry and physics as symmetry transformations are given. [ABSTRACT FROM AUTHOR]

The principles of time and space translation invariance, which result in energy and momentum conservation, are among the most fundamental and widely accepted symmetry assumptions in physics. However, it is judicious to subject such assumptions to experimental and observational scrutiny. Thus, we initiate this process by specifying a simple periodic time dependence that contravenes time translation invariance in QED, and establishing phenomenological constraints on it. Besides observational and experimental constraints on time-varying couplings, we emphasise probes of energy conservation violation such as spontaneous photon and electron pair production and the e → e γ process. [ABSTRACT FROM AUTHOR]

This is the first in a series of papers on projective positive energy representations of gauge groups. Let Ξ→M be a principal fiber bundle, and let Γc(M,Ad(Ξ)) be the group of compactly supported (local) gauge transformations. If P is a group of 'space-time symmetries' acting on Ξ→M, then a projective unitary representation of Γc(M,Ad(Ξ))⋊P is of positive energy if every 'timelike generator' p0∈p gives rise to a Hamiltonian H(p0) whose spectrum is bounded from below. Our main result shows that in the absence of fixed points for the cone of timelike generators, the projective positive energy representations of the connected component Γc(M,Ad(Ξ))0 come from 1-dimensional P-orbits. For compact M this yields a complete classification of the projective positive energy representations in terms of lowest weight representations of affine Kac-Moody algebras. For noncompact M, it yields a classification under further restrictions on the space of ground states. In the second part of this series we consider larger groups of gauge transformations, which contain also global transformations. The present results are used to localize the positive energy representations at (conformal) infinity. [ABSTRACT FROM AUTHOR]

Reciprocity is a fundamental principle that follows the time reversal symmetry of physics. However, many practical applications require breaking time reversal symmetry, hence, are called nonreciprocal. This article aims at discussing time reversal symmetry, developing fundamental building block to achieve nonreciprocity leading to robust analytical model to explain electromagnetic rotation upon propagation through a nonreciprocal medium. Detailed mathematical derivation is presented for Faraday and Kerr rotation in the presence of external bias which breaks time reversal symmetry and leads to achieve nonreciprocal system. We validate our proposed model for conventional conditions and we compute the Faraday and Kerr rotation from a reported article using our proposed mathematical model and observed excellent agreement. [ABSTRACT FROM AUTHOR]

This article reports the findings of a study of negation across varieties of English worldwide, with data derived from the Global Web‐Based Corpus of English. Three general categories are explored: negative polarity‐sensitive expressions (lexical verbs such as bother, and idioms such as give a damn); negators (idioms such as be not half bad, boilerplate no‐collocations such as no worries, and implicit negators such as bugger all); and non‐standardised features such as invariant don't and multiple negation. The findings provide support for the Inner Circle versus Outer Circle distinction, with results ascribable to such factors as evolutionary status, SLA phenomena, colloquiality, and tolerance of vulgarity. Further areal findings are suggestive of linguistic epicentrality. [ABSTRACT FROM AUTHOR]

The axion is a long-postulated boson that can simultaneously solve two fundamental problems of modern physics: the charge–parity symmetry problem in the strong interaction and the enigma of dark matter. In this work, we estimate, by means of Monte Carlo simulations, the sensitivity of the Dark-photons & Axion-Like particles Interferometer (DALI), a new-generation Fabry–Pérot haloscope proposed to probe axion dark matter in the 25–250 μ eV band. [ABSTRACT FROM AUTHOR]

Löwenstein's avoidance rule in aluminosilicates is reinterpreted on the basis of the fourth Pauling rule. It is shown that avoidance of Si–O–Si bridges may account for avoidance of Al–O–Al bridges. In view of this interpretation, it is proposed that the most favourable distributions of cations entering in substitution of silicon in the framework are associated to maximal independent sets of the respective 3‐periodic nets. Among all possible solutions, only those with maximal symmetry are realized. The applicability of the concept is demonstrated for a few natural tectosilicates, which have been analysed through the prism of their labelled quotient graph. [ABSTRACT FROM AUTHOR]

The existence of a violation of the Charge-Parity (CP) symmetry in the laws of physics is one of the cornerstone conditions for the generation of a matter–antimatter imbalance necessary to the creation of a matter-dominated universe. The first experimental evidence of the fact that this symmetry is broken in nature was obtained in 1964 in the observations of the decays of neutral kaon mesons. The magnitude of CP violation in the quark sector was measured with an increasing precision exploring also decays of other mesons. However, CP violation in the quark sector alone is not sufficient to explain the formation of matter-dominated universe, and additional sources are required. One such potential source is the lepton sector, where the CP violation could be observed by studying neutrino oscillations with neutrino beams generated by particle accelerators. This article reviews the present efforts in this direction. The results obtained in the ongoing experiments, T2K in Japan and NOvA in USA, are discussed. Additionally, the search for leptonic CP violation is one of the key goals in the programs of future experiments, DUNE in USA and Hyper-Kamiokande in Japan. These experiments and their prospects for its discovery are also presented. [ABSTRACT FROM AUTHOR]

The conformable double Elzaki composition technique (CDET) and the Adomian decomposition technique are combined in this work to provide a novel approach for dealing with nonlinear partial issues under certain specified conditions. The conformable double Elzaki composition (CDEC) approach is the name we give to this novel technique. We also outline and discuss the main traits and major conclusions connected to the recommended technique. The new technique provides an estimated succession of answers that finally get close to the exact solution. This method has the advantage of generating findings rapidly since it generates analytical series solutions for the target equations without the requirement for discretization, transformation, or limited assumptions. We also present some numerical applications to back up our conclusions. The results demonstrate the strength and potency of the recommended strategy in dealing with a variety of problems in the fields of engineering and physics in symmetry with other strategies. [ABSTRACT FROM AUTHOR]

Recently, a variety of mechanisms have been discovered that extend the range of optical techniques for identifying and characterizing molecular chirality, beyond those associated with optical polarization. It is now evident that beams of light with a twisted wavefront, known as optical vortices, can also interact with chiral matter with a specificity determined by relative handedness. Exploring this chiral sensitivity of vortex light in its interactions with matter requires careful consideration of the symmetry properties that engage in such processes. Most of the familiar measures of chirality are directly applicable to either matter, or to light itself—but only to one or the other. To elicit the principles that determine the viability of distinctly optical vortex‐based forms of chiral discrimination invites a more universal approach to symmetry analysis, as is afforded by the common, fundamental physics of CPT symmetry. Taking this approach supports a comprehensive and straightforward analysis to identify the mechanistic origins of vortex chiroptical interactions. Careful inspection of selection rules for absorption also elicits the principles governing any identifiable engagement with vortex structures, providing a reliable basis to ascertain the viability of other forms of enantioselective vortex interaction. [ABSTRACT FROM AUTHOR]

This review delves into the utilization of a sextic oscillator within the β degree of freedom of the Bohr Hamiltonian to elucidate critical-point solutions in nuclei, with a specific emphasis on the critical point associated with the β shape variable, governing transitions from spherical to deformed nuclei. To commence, an overview is presented for critical-point solutions E(5), X(5), X(3), Z(5), and Z(4). These symmetries, encapsulated in simple models, all model the β degree of freedom using an infinite square-well (ISW) potential. They are particularly useful for dissecting phase transitions from spherical to deformed nuclear shapes. The distinguishing factor among these models lies in their treatment of the γ degree of freedom. These models are rooted in a geometrical context, employing the Bohr Hamiltonian. The review then continues with the analysis of the same critical solutions but with the adoption of a sextic potential in place of the ISW potential within the β degree of freedom. The sextic oscillator, being quasi-exactly solvable (QES), allows for the derivation of exact solutions for the lower part of the energy spectrum. The outcomes of this analysis are examined in detail. Additionally, various versions of the sextic potential, while not exactly solvable, can still be tackled numerically, offering a means to establish benchmarks for criticality in the transitional path from spherical to deformed shapes. This review extends its scope to encompass related papers published in the field in the past 20 years, contributing to a comprehensive understanding of critical-point symmetries in nuclear physics. To facilitate this understanding, a map depicting the different regions of the nuclide chart where these models have been applied is provided, serving as a concise summary of their applications and implications in the realm of nuclear structure. [ABSTRACT FROM AUTHOR]

Time and space translation invariance, giving rise to energy and momentum conservation, are not only amongst the most fundamental but also the most generally accepted symmetry assumptions in physics. It is nevertheless prudent to put such assumptions to experimental and observational tests. In this note, we take the first step in this direction, specifying a simple periodic time dependence that violates time translation invariance in QED, and setting phenomenological constraints on it. In addition to observational and experimental constraints on time varying couplings, we focus on probes of violation of energy conservation such as spontaneous production of photon and electron pairs and the e → eγ process. We discuss similarities and differences to the discussion of time varying fundamental constants and to the case of a light bosonic dark matter field that usually also causes oscillating effects. [ABSTRACT FROM AUTHOR]

All-optical switches are among the most important parts of integrated photonics. Ultrahigh speed and ultralow energy consumption are two necessary indexes of all-optical switches. Traditionally, all-optical switches are based on concepts such as micro-ring resonators, surface plasmon polaritons, photonic crystals, and metamaterials. However, such platforms cannot satisfy the demand for high performance of all-optical switches. To overcome the limited response time and energy consumption, recent studies have introduced new applications of such physics as parity–time symmetry, exceptional points, topological insulators, and bound states in a continuum. Such physical concepts not only provide promising research avenues for the all-optical switch but also broaden the design channel. This is expected to achieve ultracompact, ultrafast, and high-capacity all-optical information processing. [ABSTRACT FROM AUTHOR]

In addition, this Special Issue addressed other qualitative properties of linear and nonlinear equations and systems of mathematical physics, such as scattering theory, inverse problems, variational methods, and variational calculus. One paper, [[11]], deals with the problem of determining the Hill equation (or the one-dimensional Schrödinger equation) based on its spectrum and deriving the Hill equation from the specific properties of its discriminant. The main approach to studying the problem under consideration was based on the spectral theory of differential operators as well as on the properties of the spectrum HT ht of the one-dimensional Schrödinger operator HT ht with periodic coefficients HT ht and HT ht . B Differential Equations of Mathematical Physics b : In the section on Differential Equations of Mathematical Physics, questions related to the solvability, regularity, stability, and asymptotic behavior of solutions to the equations of mathematical physics and PDE, including the hydrodynamic (Stokes equations) and Helmgotz equations, were proposed for consideration. [Extracted from the article]

Accurately predicting tunnel boring machine (TBM) performance is beneficial for excavation efficiency enhancement and risk mitigation of TBM tunneling. In this paper, we develop a long short-term memory (LSTM) based hybrid intelligent model to predict two key TBM performance parameters (advance rate and cutterhead torque). The model combines the LSTM, BN, Dropout and Dense layers to process the raw data and improve the fitting quality. The features, including the ground formation properties, tunnel route curvature, tunnel location and TBM operational parameters, are divided into historical/real-time time-varying parameters, time-invariant parameters and historical/real-time output prediction data. The effectiveness of the proposed model is verified based on a large monitoring database of the Baimang River Tunnel Project in Shenzhen, south China. We then discuss the influence of the prediction mode, neural network structure and time division interval length of historical data on the prediction accuracy. The significance evaluation of input features shows that the historical output prediction has the largest influence on the prediction accuracy, and the influence of ground properties is secondary. It is also found that the correlations between input features and the output prediction are coincident with their interrelationships with the ground properties and ease of TBM excavation. Finally, it is found that the prediction results are most affected by the total propulsion force followed by the rotation speed of the cutterhead. The established model can provide useful guidance for construction personnel to roughly grasp the possible TBM status from the prediction results when adjusting the operational parameters. [ABSTRACT FROM AUTHOR]

In this paper, we put forward an alternative interpretation of time-reversal symmetry in philosophy of physics: Humean time-reversal symmetry. According to it, time-reversal symmetry is understood as a heuristic, epistemic virtue of the best system, not as a property of the Humean mosaic. One of the consequences of this view is that one of the main arguments against a primitive direction of time is rendered harmless, which paves the way for primitivism about the direction of time. [ABSTRACT FROM AUTHOR]

The two discrete generators of the full Lorentz group O (1 , 3) in 4 D spacetime are typically chosen to be parity inversion symmetry P and time reversal symmetry T, which are responsible for the four topologically separate components of O (1 , 3) . Under general considerations of quantum field theory (QFT) with internal degrees of freedom, mirror symmetry is a natural extension of P, while C P symmetry resembles T in spacetime. In particular, mirror symmetry is critical as it doubles the full Dirac fermion representation in QFT and essentially introduces a new sector of mirror particles. Its close connection to T-duality and Calabi–Yau mirror symmetry in string theory is clarified. Extension beyond the Standard Model can then be constructed using both left- and right-handed heterotic strings guided by mirror symmetry. Many important implications such as supersymmetry, chiral anomalies, topological transitions, Higgs, neutrinos, and dark energy are discussed. [ABSTRACT FROM AUTHOR]

2-group symmetries arise in physics when a 0-form symmetry G[0] and a 1-form symmetry H[1] intertwine, forming a generalised group-like structure. Specialising to the case where both G[0] and H[1] are compact, connected, abelian groups (i.e. tori), we analyse anomalies in such 'toric 2-group symmetries' using the cobordism classification. As a warm up example, we use cobordism to study various 't Hooft anomalies (and the phases to which they are dual) in Maxwell theory defined on non-spin manifolds. For our main example, we compute the 5th spin bordism group of B|픾| where 픾 is any 2-group whose 0-form and 1-form symmetry parts are both U(1), and |픾| is the geometric realisation of the nerve of the 2-group 픾. By leveraging a variety of algebraic methods, we show that Ω 5 Spin B G ≅ ℤ / m where m is the modulus of the Postnikov class for 픾, and we reproduce the expected physics result for anomalies in 2-group symmetries that appear in 4d QED. Moving down two dimensions, we recap that any (anomalous) U(1) global symmetry in 2d can be enhanced to a toric 2-group symmetry, before showing that its associated local anomaly reduces to at most an order 2 anomaly, when the theory is defined with a spin structure. [ABSTRACT FROM AUTHOR]

The analytical solutions of the two-mode Rabi–Stark model (tmRSM) are obtained by using the Bogoliubov operators approach in s u (1 , 1) Lie algebra space, which fit the exact numerical results well. The structure of the energy spectra is related to many fundamental physics characters such as symmetry, quantum phase transition (QPT), spectral collapse etc. In this paper, the spectral structure of tmRSM is discussed analytically. The regular energy spectra are given by the zeros of the G-function, and the poles appearing in the G-function are responsible for the exceptional solutions. The double degenerate exceptional solutions could be predicted by discussing the divergence of the coefficients in the G-function. If the numerator and denominator of Ω n vanish, the lowest double degenerate exceptional solutions for the n th energy levels would be located, including the first-order QPT point, the corresponding energy ( − Δ / U) is independent of the coupling strength and the energy level, even independent of the Bargmann index q. While, the nondegenerate exceptional solutions can be reproduced by the nondegenerate exceptional G-functions, the results show that more nondegenerate exceptional solutions would be found in the subspace with larger q. Then, the regular solution and two kinds of exceptional Juddian solutions of tmRSM are accurately located. The spectral collapse energy are dependent on the strength of Stark coupling and the frequency of two-level system, and Stark coupling could results in the limit of E 0 pole line is higher than that of E n pole lines, which may cause more energy levels separate from the collapse energy. [ABSTRACT FROM AUTHOR]

This research introduces a novel approach that combines the conformable double Laplace–Sumudu transform (CDLST) and the iterative method to handle nonlinear partial problems considering some given conditions, and we call this new approach the conformable Laplace–Sumudu iterative (CDLSI) method. Furthermore, we state and discuss the main properties and the basic results related to the proposed technique. The new method provides approximate series solutions that converge to a closed form of the exact solution. The advantage of using this method is that it produces analytical series solutions for the target equations without requiring discretization, transformation, or restricted assumptions. Moreover, we present some numerical applications to defend our results. The results demonstrate the strength and efficiency of the presented method in solving various problems in the fields of physics and engineering in symmetry with other methods. [ABSTRACT FROM AUTHOR]

The newly found solutions offer applications to the design of schemes for quantum simulations and processing quantum information. Further, it is found that the Kerr nonlinearity is enhanced due to the interaction between the surface plasmon polaritons and excitons of the quantum emitters. However, at a finite temperature, for some interaction parameters, the system exhibits a zeroth-order nucleation transition between the pure ferromagnetic phase and the mixed state with coexisting ferromagnetic and paramagnetic phases. The variance of the position operator is associated with how wide or narrow a wave-packet is, the momentum variance is similarly correlated with the size of a wave-packet in momentum space, and the angular-momentum variance quantifies to what extent a wave-packet is non-spherically symmetrical. [Extracted from the article]

The recently proposed spin-flip symmetry-adapted perturbation theory (SF-SAPT) first-order exchange energy [Patkowski et al., J. Chem. Phys. 148, 164110 (2018)] enables the standard open-shell SAPT approach to treat arbitrary spin states of the weakly interacting complex. Here, we further extend first-order SF-SAPT beyond the single-exchange approximation to a complete treatment of the exchanges of electrons between monomers. This new form of the exchange correction replaces the single-exchange approximation with a more moderate single-spin-flip approximation. The newly developed expressions are applied to a number of small test systems to elucidate the quality of both approximations. They are also applied to the singlet-triplet splittings in pancake bonded dimers. The accuracy of the single-exchange approximation deteriorates at short intermolecular separations, especially for systems with few electrons and for the high-spin state of the complex. In contrast, the single-spin-flip approximation is exact for interactions involving a doublet molecule and remains highly accurate for any number of unpaired electrons. Because the single-exchange approximation affects the high-spin and low-spin states of pancake bonded complexes evenly, the resulting splitting values are of similar accuracy to those produced by the formally more accurate single-spin-flip approximation. [ABSTRACT FROM AUTHOR]

We introduce a novel coarse-grained bead-spring model for flexible polymers to systematically examine the effects of an adjusted bonded potential on the formation and stability of structural macrostates in a thermal environment. The density of states obtained in advanced replica-exchange Monte Carlo simulations is analyzed by employing the recently developed generalized microcanonical inflection-point analysis method, which enables the identification of diverse structural phases and the construction of a suitably parameterized hyperphase diagram. It reveals that icosahedral phases dominate for polymers with asymmetric and narrow bond potentials, whereas polymers with symmetric and more elastic bonds tend to form amorphous structures with non-icosahedral cores. We also observe a hierarchy in the freezing transition behavior associated with the formation of the surface layer after nucleation. [ABSTRACT FROM AUTHOR]

Recent advances in ultrafast laser technology hint at the possibility of using shaped pulses to generate deracemization via selective enantiomeric conversion; however, experimental implementation remains a challenge and has not yet been achieved. Here, we describe an experiment that can be considered an accessible intermediate step on the road towards achieving laser induced deracemization in a laboratory. Our approach consists of driving a racemic mixture of 3D oriented 3,5-difluoro-3′, 5′-dibromobiphenyl (F2H3C6–C6H3Br2) molecules with a simple train of Gaussian pulses with alternating polarization axes. We use arguments related to the geometry of the field/molecule interaction to illustrate why this will increase the amplitude of the torsional oscillations between the phenyl rings while simultaneously breaking the inversion symmetry of the dynamics between the left- and right-handed enantiomeric forms, two crucial requirements for achieving deracemization. We verify our approach using numerical simulations and show that it leads to significant and experimentally measurable differences in the internal enantiomeric structures when detected by Coulomb explosion imaging. [ABSTRACT FROM AUTHOR]

By proposing an effective method for the coupled modified Dirac equation, the effects of structure inversion asymmetry on the confined states in quantum dots of three-dimensional topological ultrathin films are investigated. It is found that the presence or absence of the quantized edge states can be controlled by the inversion asymmetry potential. The tuning of the potential to the spins of edge and nonedge states is quite different. In the presence of impurities, the mixing between the edge and nonedge states can be largely enhanced and effectively tuned by the potential. The finding will be useful to design relevant nanodevices. [ABSTRACT FROM AUTHOR]

Methods which aim at universal applicability must be able to describe both weak and strong electronic correlation with equal facility. Such methods are in short supply. The combination of symmetry projection for strong correlation and coupled cluster theory for weak correlation offers tantalizing promise to account for both on an equal footing. In order to do so, however, the coupled cluster portion of the wave function must be optimized in the presence of the symmetry projection. This paper discusses how this may be accomplished, and shows the importance of doing so for both the Hubbard model Hamiltonian and the molecular Hamiltonian, all with a computational scaling comparable to that of traditional coupled cluster theory. [ABSTRACT FROM AUTHOR]

A method is presented, which allows for the rigorous use of symmetry within the construction of multidimensional potential energy surfaces (PESs). This approach is based on a crude but very fast energy estimate, which retains the symmetry of a molecule. This enables the efficient use of coordinate systems, which mix molecular and permutational symmetry, as, for example, in the case of normal coordinates with subsets of localized normal coordinates. The impact of symmetry within the individual terms of an expansion of the PES is studied together with a symmetry consideration within the individual electronic structure calculations. A trade between symmetry within the surface and the electronic structure calculations has been observed and has been investigated in dependence on different coordinate systems. Differences occur between molecules belonging to Abelian point groups in contrast to non-Abelian groups, in which further benefits can be achieved by rotating normal coordinates belonging to degenerate vibrational frequencies. In general, the exploitation of surface symmetry was found to be very important within the construction of PESs of small and medium-sized molecules—irrespective of the coordinate system. Benchmark calculations are provided for formaldehyde, ethene, chloromethane, and cubane. [ABSTRACT FROM AUTHOR]

We derive an analytical model of diffusive thermal transport in multilayer structures of spherical symmetry and apply it to transient thermoreflectance measurements of gold nanoparticles embedded in a polymer matrix. This multilayer approach significantly improves the quantitative measurement of material thermal properties, in comparison with single-layer methods. The model adapts the typical planar transfer matrix model to a spherical geometry, and we apply it to transient thermoreflectance (TTR) experiments on gold nanoparticles embedded in a polymer matrix, to published TTR data for aqueous platinum nanoparticles, and also to example systems of aqueous gold and platinum nanoparticles. We measure a thermal boundary conductance value of 410 MW / m 2 K at the nanoparticle gold/polymer interface. The sensitivity of the TTR signal to system thermal properties is predicted as a function of the particle/matrix thermal boundary resistance (TBR), and we discuss the differentiation of TBR and capping layer effects on a TTR signal. [ABSTRACT FROM AUTHOR]

Coarse-grained (CG) molecular dynamics (MD) can simulate systems inaccessible to fine-grained (FG) MD simulations. A CG simulation decreases the degrees of freedom by mapping atoms from an FG representation into agglomerate CG particles. The FG to CG mapping is not unique. Research into systematic selection of these mappings is challenging due to their combinatorial growth with respect to the number of atoms in a molecule. Here we present a method of reducing the total count of mappings by imposing molecular topology and symmetry constraints. The count reduction is illustrated by considering all mappings for nearly 50 000 molecules. The resulting number of mapping operators is still large, so we introduce a novel hierarchical graphical approach which encodes multiple CG mapping operators. The encoding method is demonstrated for methanol and a 14-mer peptide. With the test cases, we show how the encoding can be used for automated selection of reasonable CG mapping operators. [ABSTRACT FROM AUTHOR]

This document is an editorial for a special issue titled "Symmetry in Physics of Plasma Technologies II." The special issue collects articles on various topics related to plasma technologies, including plasma-facing components for controlled thermonuclear fusion reactors, plasma processing of materials, plasma chemistry, acceleration of plasma and plasma thrusters, and symmetry issues in the physics of plasma production. The editorial highlights specific articles in the special issue, such as a comparative analysis of spectroscopic studies of tungsten and carbon deposits on plasma-facing components in fusion reactors, the use of plasma etching to modify templates for nanostructures, the modeling and performance analysis of a plasma torch reactor for municipal solid waste treatment, the effect of oxygen content in plasma composition on silicon nanoclusters in films, laboratory tests of a bi-directional plasma thruster for electric propulsion in space, and the symmetry and dimensionality of plasma configuration during plasma acceleration in the laboratory and in space. The editorial provides a brief overview of each article's content and its relevance to plasma technologies. [Extracted from the article]

The success of topological band theory and symmetry-based topological classification significantly advances our understanding of the Berry phase. Based on the critical concept of topological obstruction, efficient theoretical frameworks, including topological quantum chemistry and symmetry indicator theory, were developed, making a massive characterization of real materials possible. However, the classification of magnetic materials often involves the complexity of their unknown magnetic structures, which are often hard to know from experiments, thus, hindering the topological classification. In this paper, we design a high-throughput workflow to classify magnetic topological materials by automating the search for collinear magnetic structures and the characterization of their topological natures. We computed 1049 chosen transition-metal compounds (TMCs) without oxygen and identified 64 topological insulators and 53 semimetals, which become 73 and 26 when U correction is further considered. Due to the lack of magnetic structure information from experiments, our high-throughput predictions provide insightful reference results and make the step toward a complete diagnosis of magnetic topological materials. [ABSTRACT FROM AUTHOR]

Because HT ht is symmetric, I A i is symmetric, and so it has an orthonormal basis of eigenvectors. These vibrations span I D i , and HT ht acts transitively on them, but even this does not quite show that I D i is irreducible. Up to this point, we have assiduously avoided making explicit choices of the equilibrium positions HT ht , but it is now time to face this task. However, the two are not equal, because the same orthogonal motion of HT ht that permutes the equilibrium positions also acts on the displacements. [Extracted from the article]