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In the context of condensed matter physics, the Sommerfeld parameter describes the enhancement or suppression of free-carrier charge density in the vicinity of a charged center. The Sommerfeld parameter is known for three-dimensional systems and is integral to the description of trap-assisted recombination in solids. Here we derive the Sommerfeld parameter in one and two dimensions and compare with the results in three dimensions. We provide an approximate analytical expression for the Sommerfeld parameter in two dimensions. Our results indicate that the effect of the Sommerfeld parameter is to suppress trap-assisted recombination in decreased dimensionality.

We explore a mechanism for ionization in high-velocity (but not yet relativistic) collisions of light atomic particles, one of which being initially in an excited internal state. This mechanism is driven by the generalized Breit interaction and proceeds via radiative energy transport between the colliding particles which has an extremely long range. A comparison of this mechanism with those which are 'standard' for high-velocity collisions shows that it can play a noticeable role in collisions with excited target atoms. [ABSTRACT FROM AUTHOR]

A hypothesis is proposed for a change in the spin state of a two-center two-electron bond of a reacting molecule under the perturbing action of an organic radical. The hypothesis opens up new possibilities for refining the mechanism of radical bonding to olefins and conjugated dienes. A change in the spin state of the ethylene and s-trans-butadiene-1,3 molecules creates prerequisites for one-electron transfer in the reaction system. Single-electron transfer changes the distribution of effective charges on the atoms of the reaction system, ensuring their Coulomb interaction and allowing us to interpret the formation of final products in the context of a fundamental physical interaction (electromagnetic). [ABSTRACT FROM AUTHOR]

We explore novel optomechanically induced transparency (OMIT) and prolonged slow light in a linear and quadratic optomechanical system (OMS) with the Coulomb coupling. The hybrid OMS includes a Fabry–Pérot cavity and two charged mechanical resonators (MR1 inside the cavity and MR2 outside the cavity), where the interaction between the charged MR1 and the cavity field are both linear and quadratic in the MR1's displacement, and the charged MR1 and the charged MR2 mutually coupled via Coulomb interaction. Specifically, the transmission of the output field exhibits three transparency window dips. The Coulomb coupling strength is responsible for creating two transparency window dips near δ / ω m = 1 , which results from the mechanical dressed mode. Simultaneously, the quadratic coupling between the charged MR1 and the optical cavity field significantly contributes to another transparency window dip near δ / ω m = 2 , which is attributed to the two-phonon process. In addition, by adjusting the value of Coulomb coupling strength, linear (quadratic) coupling and frequency of the two mechanical resonators, one can attain prolonged slow light with a group delay extending to tens of milliseconds. Furthermore, the positive (negative) value of quadratic coupling strength can determine the switching behavior of the group delay (i.e., from superluminal to subluminal propagation) on the right (left) side of δ / ω m = 2 . We believe that the results have potential applications in manipulating the performance of OMIT devices and optical switching. [ABSTRACT FROM AUTHOR]

We describe a time-dependent functional involving the relative entropy and the P H1 seminorm, which decreases along solutions to the spatially homogeneous Landau equation with Coulomb potential. The study of this monotone functional sheds light on the competition between dissipation and nonlinearity for this equation. It enables us to obtain new results concerning regularity/ blowup issues for the Landau equation with Coulomb potential. [ABSTRACT FROM AUTHOR]

This work explains that the Coulomb elastic process on the nucleus is a major source of single-event effects (SEE) for protons within the energy range of 1–10 MeV. The infinite range of Coulomb interactions implies an exceptionally high recoil probability. This research seeks to extend the investigations under which the elastic process becomes significant in the energy deposition process by providing a simplified methodology to evaluate the elastic contribution impact on the reliability of electronics. The goal is to derive a method to provide a simple way to calculate and predict the SEE cross-section. At very low energy, we observe a significant increase in the proton differential cross-section. The use of a direct Monte Carlo approach would mainly trigger low energy recoiling ions, and a very long calculation time would be necessary to observe the tail of the spectrum. In this sense, this work provides a simple methodology to calculate the SEE cross-section. The single-event upset (SEU) cross-section results demonstrate a good agreement with the experimental data in terms of shape and order of magnitude for different technological nodes.

Despite the abundant reserves and high theoretical capacity of Na–S batteries, it is still limited by the sluggish reaction kinetics of polysulfides during ultrafast charging and discharging to provide stable and high sodium-ion storage performance. Herein, a catalytic strategy is proposed to change the direction of the Coulomb interaction of S–S bonds to achieve high rate reaction kinetics in polysulfides. In this strategy, a NaxVS2 structure is constructed in VS2/S nanocomposite electrodes to support S for superior performance (784 mA h/g at 0.1 A/g and 512 mA h/g at 10 A/g) during sodium storage process. The electrode can still exhibit stable cycling performance at a very high current density (5000 cycles at 20 A/g). The Na-inserted VS2 (NaxVS2) changes the charge distribution of S in polysulfide molecules, altering the Coulomb interaction between S atoms in polysulfide to form repulsion-induced breaking of S–S bond. This altering effect on the atomic Coulomb interaction is essential to promoting the conversion reaction of polysulfides. The above strategy of changing the Coulomb interaction between S atoms not only provides a reference for the design of nanostructures for electrochemical processes with multistep reactions but also inspires angles and ideas for realizing high-performance Na–S batteries. [ABSTRACT FROM AUTHOR]

The infamous numerical sign problem poses a fundamental obstacle to particle-based stochastic Wigner simulations in high-dimensional phase space. Although the existing particle annihilation (PA) via uniform mesh significantly alleviates the sign problem when dimensionality D ≤ 4, the mesh size grows dramatically when D ≥ 6 due to the curse of dimensionality and consequently makes the annihilation very inefficient. In this paper, we propose an adaptive PA algorithm, termed sequential-clustering particle annihilation via discrepancy estimation (SPADE), to overcome the sign problem. SPADE follows a divide-and-conquer strategy: adaptive clustering of particles via controlling their number-theoretic discrepancies and independent random matching in each cluster. The target is to alleviate the oversampling problem induced by the overpartitioning of phase space and to capture the nonclassicality of the Wigner function simultaneously. Combining SPADE with the variance reduction technique based on the stationary phase approximation, we attempt to simulate the proton-electron couplings in six- and 12-dimensional phase space. A thorough performance benchmark of SPADE is provided with the reference solutions in six-dimensional phase space produced by a characteristic-spectral-mixed scheme under a 73³ × 80³ uniform grid, which fully explores the limit of grid-based deterministic Wigner solvers. [ABSTRACT FROM AUTHOR]

We are investigating the quantum geometric speed limit (QSL) for a Hubbard-type fermionic dimer subjected to the effects of decoherence and driving. The influence of decoherence is explored through the utilization of three distinct models that describe weak connections between the dimer and its environment, employing the Davies approximation. We consider two different types of driving: adiabatic driving and white noise stochastic driving. Our findings demonstrate that the properties of the geometric QSL are affected by both the on-site and inter-site Coulomb interactions among the fermions in the dimer. The interplay between Coulomb interactions and the influence or control exerted by external classical or quantum noise results in distinct time regimes for the evolution of the dimer, characterized by specific and potentially desirable QSL properties. [ABSTRACT FROM AUTHOR]

This work explains that the Coulomb elastic process on the nucleus is a major source of single-event effects (SEE) for protons within the energy range of 1–10 MeV. The infinite range of Coulomb interactions implies an exceptionally high recoil probability. This research seeks to extend the investigations under which the elastic process becomes significant in the energy deposition process by providing a simplified methodology to evaluate the elastic contribution impact on the reliability of electronics. The goal is to derive a method to provide a simple way to calculate and predict the SEE cross-section. At very low energy, we observe a significant increase in the proton differential cross-section. The use of a direct Monte Carlo approach would mainly trigger low energy recoiling ions, and a very long calculation time would be necessary to observe the tail of the spectrum. In this sense, this work provides a simple methodology to calculate the SEE cross-section. The single-event upset (SEU) cross-section results demonstrate a good agreement with the experimental data in terms of shape and order of magnitude for different technological nodes. [ABSTRACT FROM AUTHOR]

It is of great significance to develop high‐performance n‐type ionic thermoelectric materials. Herein, the turnover from p‐ to n‐type and great improvement in the n‐type ionic Seebeck coefficient of ionogels through synergistic dopings of cations and anions, is reported. Doping with silver trifluoromethanesulfonate (AgOTf) can turn the ionic Seebeck coefficient of the ionogels consisting of poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) and 1‐butyl‐3‐methylimidazolium tetrafluoroborate (BMIM:BF4) from 5.52 to −26.4 mV K−1 under a relative humidity (RH) of 75%. The TE performances can be further improved through the combination with the anti‐solvent method, and the ZTi value can be up to 1.7 under 91% RH, the highest for n‐type ionogels. Such p‐ to n‐type turnover and great improvement in the n‐type ionic Seebeck coefficient can be attributed to synergistic doping by Ag+ and OTf−. Ag+ can form a complex with BMIM+, and OTf− can have strong Coulomb interaction to BMIM+. Both can retard the migration of the BMIM+ cations and thus increase the difference in the mobilities of BMIM+ and BF4−. This is the first time that synergistic dopings by both cations and anions for ionic TE materials has been observed. [ABSTRACT FROM AUTHOR]

It is common in mesoscopic systems to find instances where several charges interact among themselves. These particles are usually confined by an external potential that shapes the symmetry of the equilibrium charge configuration. In the case of classical charges moving on a plane and repelling each other via the Coulomb potential, they possess a ground state à la Thomson or Wigner crystal. As the number of particles N increases, the number of local minima grows exponentially and direct or heuristic optimization methods become prohibitively costly. Therefore the only feasible approximation to the problem is to treat the system in the continuum limit. Since the underlying framework is provided by potential theory, we shall by‐pass the corresponding mathematical formalism and list the most common cases found in the literature. Then we prove a (albeit known) mathematical correspondence that will enable us to re‐discover analytical results in electrostatics. In doing so, we shall provide different methods for finding the equilibrium surface density of charges, analytical and numerical. Additionally, new systems of confined charges in three‐dimensional surfaces will be under scrutiny. Finally, we shall highlight exact results regarding a modified power‐law Coulomb potential in the d‐dimensional ball, thus generalizing the existing literature. [ABSTRACT FROM AUTHOR]

The puzzle of the direct dark matter search can be resolved by examining the concept of «dark atoms», which consist of hypothetical stable lepton-like particles with a charge of − 2 n , where n is any natural number, bound to n nuclei of primordial helium. These «dark atoms», known as «XHe» (X-helium) atoms, remain undiscovered in experiments due to their neutral atom-like states. In this model, the positive results of the D A M A / N a I and D A M A / L I B R A experiments could be explained by the annual modulation of radiative capture of XHe atoms engaging in low-energy bound states with sodium nuclei. This specific phenomenon does not occur under the conditions of other underground experiments. The proposed solution to this puzzle involves establishing the existence of a low-energy bound state of «dark atoms» and nuclei while also considering the self-consistent influence of nuclear attraction and Coulomb repulsion. Resolving this complex issue, which has remained unsolved for the past 17 years, necessitates a systematic approach. To tackle this problem, numerical modeling is employed to uncover the fundamental processes behind the interaction of «dark atoms» with nuclei. To comprehend the essence of XHe's interaction with baryonic matter nuclei, a classical model is employed wherein quantum physics and nuclear size effects are progressively incorporated. A numerical model describing the interaction between XHe «dark atoms» and nuclei is developed through the continuous inclusion of realistic features of quantum mechanics in the initial classical three-body problem involving the X-particle, the helium nucleus, and the target nucleus. This approach yields a comprehensive numerical model that encompasses nuclear attraction and electromagnetic interaction between the «dark atom» and nuclei. Finally, this model aids in supporting the interpretation of the results obtained from direct underground dark matter experiments through the lens of the «dark atom» hypothesis. [ABSTRACT FROM AUTHOR]

The time evolution of the continuous measure of symmetry for a system built of three bodies interacting via the potential U (r) ~ 1 r is reported. Gravitational and electrostatic interactions between the point bodies were addressed. In the case of a pure gravitational interaction, the three-body-system deviated from its initial symmetrical location, described by the Lagrange equilateral triangle, comes eventually to collapse, accompanied by the growth of the continuous measure of symmetry. When three point bodies interact via the repulsive Coulomb interaction, the time evolution of the CMS is quite different. The CMS calculated for all of the studied initial configurations of the point charges, and all of their charge-to-mass ratios, always comes to its asymptotic value with time, evidencing the stabilization of the shape of the triangle, constituted by the interacting bodies. The influence of Stokes-like friction on the change in symmetry of three-body gravitating systems is elucidated; the Stokes-like friction slows the decrease in the CMS and increases the stability of the Lagrange triangle. [ABSTRACT FROM AUTHOR]

Numerical resolution for 6-D Wigner dynamics under the Coulomb potential is faced with the combined challenges of high dimensionality, nonlocality, oscillation, and singularity. In particular, the extremely huge memory storage of 6-D grids hinders the usage of all existing deterministic numerical schemes, which is well known as the curse of dimensionality. To surmount these difficulties, we propose a massively parallel solver, termed the characteristic-spectral-mixed (CHASM) scheme, by fully exploiting two distinct features of the Wigner equation: locality of spatial advection and nonlocality of quantum interaction. Our scheme utilizes the local cubic B-spline basis to interpolate the local spatial advection. The key is to use a perfectly matched boundary condition to give a closure of spline coefficients, so that distributed pieces can recover the global one as accurately as possible owing to the rapid decay of wavelet basis in the dual space, and communication costs are significantly reduced. To resolve the nonlocal pseudodifferential operator with a singular symbol, CHASM further adopts the truncated kernel method to attain a highly efficient approximation. Several typical experiments including the quantum harmonic oscillator and the 1s state of hydrogen demonstrate the accuracy and efficiency of CHASM. Nonequilibrium electron-proton couplings are also clearly displayed and illuminate the uncertainty principle and quantum tunneling in phase space. Finally, the scalability of CHASM up to 16000 cores is presented. [ABSTRACT FROM AUTHOR]

The variations of exchange Slater integrals with respect to their order k are not well known. While direct Slater integrals Fk are positive and decreasing when the order increases, this is not stricto sensu the case for exchange integrals Gk. However, two inequalities were published by Racah in his seminal article 'Theory of complex spectra. II'. In this article, we show that the technique used by Racah can be generalized, albeit with cumbersome calculations, to derive further relations, and provide two of them, involving respectively three and four exchange integrals. Such relations can prove useful to detect regularities in complex atomic spectra and classify energy levels. [ABSTRACT FROM AUTHOR]

A comprehensive detailed computational investigation of the structural, electronic, magnetic, and mechanical properties of Fe2XAs (X = Mn and Co) Full Heusler Alloy is performed using density functional theory (DFT). Our results reveal that the stable crystal structure of both alloys is the L21 prototype. Also, Fe2MnAs exhibit a half-metallic behavior characterized by a 100% spin polarization at the Fermi level. Furthermore, both alloys possess significant magnetic moments while a high Curie temperature is observed for Fe2CoAs alloy highlighting their suitability for various technological applications. Furthermore, we provide insights into the effect of tetragonal distortion, elucidating their performance under high-pressure conditions.

We present a numerical investigation on the impact of the Coulomb interaction in the spiderlike photoelectron momentum distributions (PMDs) of a hydrogen atom ionized by an intense laser pulse. We have shown, by integrating analytical correction terms into the standard semiclassical rescattering model (SRM) to formulate the Coulomb analytically-corrected SRM (AC-SRM), that the interference fringes manifest a systematic shift along the transverse momentum direction upon considering the Coulomb action. A Coulomb correction to the SRM model has rarely been reported before. Analyses are made by varying physical quantities such as the carrier frequency and initial transverse velocity of the ionized electron. In particular, we decipher the impact of the Coulomb interaction with the classical-action phase map scheme, and demonstrate that this effect is more pronounced for smaller momenta in the spiderlike PMDs. It is proven that the presented AC-SRM is simple and effective in accounting for the Coulomb effect, as an alternative correction due to the Coulomb interaction to the standard SRM theory. Also, our phase map scheme is shown to be more powerful than the plain interference fringes in interrogating the Coulomb effect, especially for the first interference minimum. We anticipate that the present AC-SRM can be useful in investigating other strong field processes where the Coulomb interaction is considered. [ABSTRACT FROM AUTHOR]

High‐capacity anode materials are promising candidates for increasing the energy density of lithium (Li)‐ion batteries due to their high theoretical capacities. However, a rapid capacity fading due to the huge volume changes during charge‐discharge cycles limits practical applications. Herein, a layering‐charged polymeric binder is introduced that can effectively integrate high‐capacity anodes using a strong yet reversible Coulomb interaction and enriched hydrogen bonding. The charged polymeric binder builds a dynamically charge‐directed network on the active materials with high versatility and efficiently dissipates the electrode stress with its excellent mechanical properties. In addition, poly(ethylene glycol) (PEG) moieties of the charged binder offer a fast Li‐ion conduction pathway that can form an ultra‐thick silicon oxide (SiOx)‐based electrode (≈10.2 mAh cm−2) without compromising the reversible specific capacity and promote effective charge interaction as a mechanical modulator. Such an unprecedented charge‐directed binder provides insights into the rational design of a binder for high‐capacity anodes. [ABSTRACT FROM AUTHOR]

Fast and continuous ion insertion is blocked in the common electrodes operating with widely accepted single‐ion storage mechanism, primarily due to Coulomb repulsion between the same ions. It results in an irreconcilable conflict between capacity and rate performance. Herein, we designed a porous organic framework with novel multiple‐ion co‐storage modes, including PF6−/Li+, OTF−/Mg2+, and OTF−/Zn2+ co‐storage. The Coulomb interactions between cationic and anionic carriers in the framework can significantly promote electrode kinetics, by rejuvenating fast ion carrier migration toward framework interior. Consequently, the framework via PF6−/Li+ co‐storage mode shows a high energy density of 878 Wh kg−1 cycled more than 20 000 cycles, with an excellent power density of 28 kW kg−1 that is already comparable to commercial supercapacitors. The both greatly improved energy and power densities via the co‐storage mode may pave a way for exploring new electrodes that are not available from common single‐ion electrodes. [ABSTRACT FROM AUTHOR]

This paper is dedicated to studying the magnetic field effects on the physical properties of the AB bilayer graphene. We consider the generalized Hubbard model to study the physical properties in the AB staked bilayer graphene exposed to the external magnetic field and applied electric field potential. We calculated a series of physical parameters in the system numerically as a function of the magnetic field and electric field potential. Different site-filling regimes have been considered and their influence on the behavior of the calculated physical parameters has been studied. We show that at the half-filling and high magnetic field values the charge neutrality is attained in the bilayer graphene, while at the partial-filling the system gets only charge-stabilized. Moreover, for both filling regimes, we have found a narrow region of the magnetic field parameter, where the excitonic pairing interaction survives. [ABSTRACT FROM AUTHOR]

The generalized Born (GB) model is an extension of the continuum dielectric theory of Born solvation energy and is a powerful method for accelerating the molecular dynamic (MD) simulations of charged biological molecules in water. While the effective dielectric constant of water that varies as a function of the separation distance between solute molecules is incorporated into the GB model, adjustment of the parameters is indispensable for accurate calculation of the Coulomb (electrostatic) energy. One of the key parameters is the lower limit of the spatial integral of the energy density of the electric field around a charged atom, known as the intrinsic radius ρ. Although ad hoc adjustment of ρ has been conducted to improve the Coulombic (ionic) bond stability, the physical mechanism by which ρ affects the Coulomb energy remains unclear. Via energetic analysis of three differently sized systems, here, we clarify that the Coulomb bond stability increases with increasing ρ and that the increased stability is caused by the interaction energy term, not by the self-energy (desolvation energy) term, as was supposed previously. Our results suggest that the use of larger values for the intrinsic radii of hydrogen and oxygen atoms, together with the use of a relatively small value for the spatial integration cutoff in the GB model, can better reproduce the Coulombic attraction between protein molecules. [ABSTRACT FROM AUTHOR]

To get a carbon-based qubit, we pay attention to the two-electron conduction band of a graphene quantum dot (GQD) in the presence of an external magnetic field and an extrinsic Rashba spin-orbit interaction (SOI). To help understand the formation of the two-electron spectra, we first calculate the tight-binding (TB) spectra. There exist the sensitivity of the conduction band to magnetic fields and the mixing of spin states induced by a Rashba SOI. The two factors inspire the study of the magnetic-field modulation of the conduction band for realizing a spin qubit. We present the method for calculating the electronic structure of a few-electron GQD. The roles of the Coulomb interaction and the Rashba SOI in the two-electron conduction band are investigated. The Coulomb interaction contributes to a singlet-triplet level crossing and the Rashba SOI leads to a singlet-triplet mixing. The fast initialization and coherent manipulation of spin states are demonstrated by the magnetic control of singlet-triplet splitting.

The time evolution of the continuous measure of symmetry for a system built of three bodies interacting via the potential U(r)~1r is reported. Gravitational and electrostatic interactions between the point bodies were addressed. In the case of a pure gravitational interaction, the three-body-system deviated from its initial symmetrical location, described by the Lagrange equilateral triangle, comes eventually to collapse, accompanied by the growth of the continuous measure of symmetry. When three point bodies interact via the repulsive Coulomb interaction, the time evolution of the CMS is quite different. The CMS calculated for all of the studied initial configurations of the point charges, and all of their charge-to-mass ratios, always comes to its asymptotic value with time, evidencing the stabilization of the shape of the triangle, constituted by the interacting bodies. The influence of Stokes-like friction on the change in symmetry of three-body gravitating systems is elucidated; the Stokes-like friction slows the decrease in the CMS and increases the stability of the Lagrange triangle.

An estimate of the dynamic effect the electric fields of a charged sphere on a current-carrying conductor is obtained. The characteristic time parameter of charge transfer to a conducting sphere, as well as the momentum Conservation Principle are applied. The found values of the interaction force and the transmitted energy can make it possible to determine the physical nature of the dynamic effect. A description of the laboratory setup is presented.

We study the low-energy deuteron-deuteron elastic scattering using the cluster effective field theory formalism up to next-to-leading order (NLO). For this purpose, we initially focus on determination of the unknown effective field theory coupling constant values using the phase shift analysis and available differential cross section data. The differential cross section versus center of mass energy and scattering angle are plotted up to NLO in the suggested power counting and compared to the available experimental data. Our effective field theory results show good consistency with the experimental data. [ABSTRACT FROM AUTHOR]

We consider a PDE which describes the evolution of an electric charge distribution in one spatial dimension. Due to the (singular) electrostatic interaction, the PDE is nonlocal. Moreover, the PDE describes the neutralization of charge at points where the charge distribution changes sign. Despite these complex features of the PDE, we develop a simple scheme to solve the PDE numerically. We demonstrate by means of simulations that the scheme is accurate and that it preserves the (expected) properties of the exact solution. [ABSTRACT FROM AUTHOR]

The absorptive property of a ring optomechanical cavity is theoretically studied by coupling a charged nanomechanical resonator via Coulomb interaction. The multiple optomechanically induced transparency windows in the output field are observed. The results show that in a ring optomechanical cavity with two movable mirrors the output field presents two transparency windows. The two transparency windows split into three transparency windows when the third movable mirror is added by Coulomb interaction in this optomechanical system. We find that the distance between transparency windows is changed, but the width of each transparency window still remains unchanged when the Coulomb interaction strength is modulated. The width of each transparency window can be widened with the increase in pump power. [ABSTRACT FROM AUTHOR]

We formulate an analytically-corrected semiclassical rescattering model (AC-SRM) by including analytical correction terms of Coulomb interaction into the standard SRM theory. By using the simple but effective AC-SRM, we perform extensive numerical simulation of the spiderlike photoelectron momentum distributions (PMDs) of hydrogen atom ionized by intense laser pulse. It is shown that the spiderlike structure in the PMDs manifests a systematic shift along the transverse momentum direction upon considering the Coulomb action. This shift is deciphered with a phase map scheme and trajectory analysis, with the former being particularly powerful for the most important first interference minimum of the spiderlike feature. The simulation reveals that the proposed AC-SRM is physically transparent and its computational implementation is economical. In addition, we propose a physical picture of the Coulomb action as a phase increment of the initial longitudinal momentum of the ionized electron. [ABSTRACT FROM AUTHOR]

We investigated the role of the bonding environment and Coulomb screening in the van der Waals (vdW) metallic ferromagnets Fe3GeTe2 (FGT3) and Fe4GeTe2 (FGT4). The electronic origins of the contrasting magnetic anisotropy of FGT3 and FGT4 were examined using X-ray absorption spectroscopy (XAS) and ab initio calculations. We found that the orbital magnetic moment of FGT4 (0.050 μB/Fe) is smaller than that of FGT3 (0.11 μB/Fe). Here, the difference in Fe dumbbell structure gives rise to the more (less) localized d3z2–r2 states in FGT3-(FGT4), and an effective orbital level splitting of t2g manifolds results in the large magnetocrystalline anisotropy in FGT3. The XAS measurements and the calculations additionally show that the Coulomb interaction is more effectively screened in FGT4 than in FGT3. The following theoretical analyses show that the screened Coulomb interaction becomes a key parameter to determine the magnetic anisotropy energy, especially in the thickness dependence. Finally, we discuss that the recent experimental demonstrations can be understood upon the effect of the bonding environment. Our investigation reveals essential electronic degrees of freedom to control the magnetism of the vdW ferromagnet for ultrathin nano devices. [ABSTRACT FROM AUTHOR]

Most near‐infrared (NIR) light‐responsive photocatalysts inevitably suffer from low charge separation due to the elevated Coulomb interaction between electrons and holes. Here, an n‐type doping strategy of alkaline earth metal ions is proposed in crystalline K+ implanted polymeric carbon nitride (KCN) for visible and NIR photoactivity. The n‐type doping significantly increases the electron densities and activates the n→π* electron transitions, producing NIR light absorption. In addition, the more localized valence band (VB) and the regulation of carrier effective mass and band decomposed charge density, as well as the improved conductivity by 1–2 orders of magnitude facilitate the charge transfer and separation. The proposed n‐type doping strategy improves the carrier mobility and conductivity, activates the n→π* electron transitions for NIR light absorption, and breaks the limitation of poor charge separation caused by the elevated Coulomb interaction. [ABSTRACT FROM AUTHOR]

The Jost functions, constructed by fitting available partial cross-sections for the elastic p7Be scattering with J π = 3 + , 2 − , are analytically continued to complex energies, where the resonances are located as their zeros. In addition to the resonance energies and widths, the residues of the S -matrix at the corresponding poles, as well as the Asymptotic Normalization Constants (ANC) are determined. The fitting is done using the semi-analytic representation of the Jost function with proper analytic structure, defined on the Riemann surface whose topology involves not only the square-root but also the logarithmic branching caused by the Coulomb interaction. [ABSTRACT FROM AUTHOR]

Here, we propose a multimode optomechanical system for achieving an adjustable quantum coherence effect (the ideal optical nonreciprocity response), where two linearly coupled cavity modes and a charged mechanical mode are coupled to another charged mechanical mode. Two strong pump laser fields (weak probe laser fields) are used to drive two cavity modes, respectively. When the system works under certain conditions, we can obtain the ideal optical nonreciprocity response. The ideal optical nonreciprocity response direction can be controlled by the phase differences. This optical nonreciprocity response results from the constructive or destruction interference between different transmission paths in this multimode optomechanical system. We also show that the optical nonreciprocity response can be adjusted by the cavity decay rate, Coulomb coupling strength, intercavity tunneling strength. [ABSTRACT FROM AUTHOR]

Monitoring the blood concentration of banoxantrone (AQ4N) is important to evaluate the therapeutic efficacy and side effects of this new anticancer prodrug during its clinical applications. Herein, we report a fluorescence method for AQ4N detection through the modulation of the molecule-like photoinduced electron transfer (PET) behavior of gold nanoclusters (AuNCs). AQ4N can electrostatically bind to the surface of carboxylated chitosan (CC) and dithiothreitol (DTT) co-stabilized AuNCs and quench their fluorescence via a Coulomb interaction-accelerated PET process. Under optimized experimental conditions, the linear range of AQ4N is from 25 to 200 nM and the limit of detection is as low as 5 nM. In addition, this assay is confirmed to be reliable based on its successful use in AQ4N determination in mouse plasma samples. This work offers an effective strategy for AQ4N sensing based on fluorescent AuNCs and widens the application of AuNCs in clinical diagnosis and pharmaceutical analysis. [ABSTRACT FROM AUTHOR]

Abstract Most near‐infrared (NIR) light‐responsive photocatalysts inevitably suffer from low charge separation due to the elevated Coulomb interaction between electrons and holes. Here, an n‐type doping strategy of alkaline earth metal ions is proposed in crystalline K+ implanted polymeric carbon nitride (KCN) for visible and NIR photoactivity. The n‐type doping significantly increases the electron densities and activates the n→π* electron transitions, producing NIR light absorption. In addition, the more localized valence band (VB) and the regulation of carrier effective mass and band decomposed charge density, as well as the improved conductivity by 1–2 orders of magnitude facilitate the charge transfer and separation. The proposed n‐type doping strategy improves the carrier mobility and conductivity, activates the n→π* electron transitions for NIR light absorption, and breaks the limitation of poor charge separation caused by the elevated Coulomb interaction.

Electronic structures of heavy-hole trions and He-isoelectronic ions show dependence on transitions among two-electron bound states constituted of hydrogenic orbitals for which Coulomb (exchange) interaction causes nontrivial secular divergence to Schrödinger equation (SE). Coulomb interaction between a pair of electrons triggers nonadiabatic transitions due conical intersections and larger vibrational amplitudes of nuclei. Therefore, existing state-of-art theories ubiquitously urge analytical integrals for multipoles of electrostatic Green’s function expansion. Born–Oppenheimer (BO) approximation separates the hamiltonian into electronic and nuclear coordinates at adiabatic limit. Employing associated Laguerre polynomial and Whittaker-M function basis sets of hydrogenic orbitals for the pair of electrons (electronic coordinate) furnishes analytical, terminable, simple and finitely summed integrals in terms of Lauricella functions. The exact integrals also remedy the difficulty arisen from different scaling factors of bound states for higher order perturbation calculations. Analytical perturbation calculations for monopole and dipole factors using singly and doubly excited states (|n2sn4s〉, |n2pn4p〉) with spherical and dumbbell symmetries show sufficient convergence of ground-state energy correction of He-isoelectronic series within 0.20–6.89% of reported results. Calculation of current-density with ground-state upto first order perturbation correction clearly shows that singly and doubly excited spherically symmetric states do not contribute to local current of He-isoelectronic series for monopole factor. Binding energies of heavy-hole trions of transition metal dichalcogenides (TMDCs) are found to be in good agreement with experimentally observed values.

The optical absorption coefficient in GaAs/AlGaAs cylindrical parabolic quantum wire (QW) with an applied static-electric field is studied in detail. The Schrödinger equation is solved within the effective mass approximation and an analytical solution is used for the electronic structure of cylindrical QW. The main aim is to clarify the effect of the Coulomb interaction on the exciton-related optical absorption of a QW with no assumptions about the strength of the confinement. Finally, it is clearly shown that the further confinement due to Coulomb interaction in a quantum wire increases the transition energy, dipole matrix elements, and absorption peaks, and results with the blue shift. One cannot neglect the Coulomb interaction in the absorption calculations. [ABSTRACT FROM AUTHOR]

The generalized Born (GB) model is an extension of the continuum dielectric theory of Born solvation energy and is a powerful method for accelerating the molecular dynamic (MD) simulations of charged biological molecules in water. While the effective dielectric constant of water that varies as a function of the separation distance between solute molecules is incorporated into the GB model, adjustment of the parameters is indispensable for accurate calculation of the Coulomb (electrostatic) energy. One of the key parameters is the lower limit of the spatial integral of the energy density of the electric field around a charged atom, known as the intrinsic radius ρ. Although ad hoc adjustment of ρ has been conducted to improve the Coulombic (ionic) bond stability, the physical mechanism by which ρ affects the Coulomb energy remains unclear. Via energetic analysis of three differently sized systems, here, we clarify that the Coulomb bond stability increases with increasing ρ and that the increased stability is caused by the interaction energy term, not by the self-energy (desolvation energy) term, as was supposed previously. Our results suggest that the use of larger values for the intrinsic radii of hydrogen and oxygen atoms, together with the use of a relatively small value for the spatial integration cutoff in the GB model, can better reproduce the Coulombic attraction between protein molecules.

We investigate the geometry of the repulsive Rutherford scattering, showing that it casts a shadow which we analyze in various reference frames. [ABSTRACT FROM AUTHOR]

We theoretically study the stationary entanglement of two charged nanomechanical oscillators coupling via Coulomb interaction in an optomechanical system with an additional Kerr medium. We show that the degree of entanglementbetween two nanomechanical oscillators is suppressed by Kerr interaction dueto photon blockade and enhanced by Coulomb coupling strength. We also show other parameters for adjusting and obtaining entanglement, such as the driving power and the frequencies of the two oscillators, and the entanglement is robust against temperature. Our study proves a way for adjusting stationary entanglement between two optomechanical oscillators by Coulomb interaction and Kerr medium. [ABSTRACT FROM AUTHOR]

We discuss the theoretical basis of the Boltzmann transport equation (BTE) and the Monte Carlo (MC) simulation scheme to take into account the discrete nature of impurities in semiconductor substrates. This is achieved by explicitly considering the self-consistent coupling between the BTE and Poisson’s equation and by separating the impurity potential into long- and short-range parts in those equations. We show that the Hartree potential is represented by the long-range part of the potential, whereas the scattering potential for the BTE is naturally derived within the framework, rather than an ad hoc assumption. The proposed scheme is validated by showing that MC simulations with discrete impurities in bulk can reproduce the conventional simulation results with the “jellium” impurity. Also, by including both static and dynamic potential fluctuations, the MC simulation can predict the correct mobility even under discrete impurities. [ABSTRACT FROM AUTHOR]

We prove a quantitative and global in time semiclassical limit from the Hartree to the Vlasov equation in the case of a singular interaction potential in dimension d ≥ 3 , including the case of a Coulomb singularity in dimension d = 3. This result holds for initial data concentrated enough in the sense that some space moments are initially sufficiently small. As an intermediate result, we also obtain quantitative bounds on the space and velocity moments of even order and the asymptotic behavior of the spatial density due to dispersion effects, uniform in the Planck constant ħ. [ABSTRACT FROM AUTHOR]

Molecular-type bound states of two-dimensional (2D) magnetoexcitons supplementarily subjected to the action of an external electric field perpendicular to the layer and parallel to a strong magnetic field are studied. The electron and hole wave functions have different numbers of the Landau quantization levels for different spin projections. The Rashba spin–orbit coupling (RSOC) is characterized by first-order chirality terms for electrons and third-order chirality terms for heavy holes in GaAs-type quantum wells. In this case, the external electric field gives rise to the nonparabolic dispersion law of heavy holes and a nonmonotonous dependence of their energy levels on the magnetic field strength. The spinor-type wave functions of electrons and holes for their lowest energy levels are used to construct the one- and two-magnetoexciton wave functions to determine their normalization conditions, and deduce the Hamiltonian of the Coulomb electron– electron interaction in the presence of the RSOC. It contains electron and hole imprint factors, the difference of which determines the affinities of the electron–hole pairs to interact between themselves. The average value of the Coulomb interaction Hamiltonian makes it possible to calculate the mean energy value per two pairs forming the molecule versus parameter α of the wave function, which determines the relative motion of two magnetoexcitons in the frame of the bound state. The next numerical calculations will show whether the stable bound state of the molecular type or the metastable bound state does exist.Au fost cercetate stările legate de tip molecular ale magnetoexcitonilor bi-dimensionali (2D) supuși suplimentar acțiunii câmpului electric extern perpendicular pe strat și paralel cu câmpul magnetic puternic. Funcțiile de undă asociate electronilor și golurilor au numere diferite ale nivelelor de cuantificare Landau pentru diferite proiecții de spin. Cuplarea spin-orbită de tip Rashba (RSOC) se caracterizează prin termeni de chiralitate de prim ordin pentru electroni și prin termeni de chiralitate de ordinul al treilea pentru golurile grele din gropile cuantice de tip GaAs. În acest caz, câmpul electric extern provoacă apariția dispersiei non-parabolice a golurilor grele și dependența non-monotonă a nivelelor de сuantificare de forța câmpului magnetic. Pentru a construi funcțiile de undă ale excitonului magnetic și ale bimagnetoexcitonului, pentru a determina condițiile de normalizare ale acestora și pentru a deduce Hamiltonianul interacțiunii Coulombiene electron-electron în prezența RSOC, au fost selectate funcțiile de undă de tip spinor ale celor mai mici nivele energetice ale electronilor și golurilor. Ele conțin factori de imprimare ale electronilor și a golurilor, a căror diferență determină afinitățile perechilor e-h să interacționeze între ele. Valoarea medie a Hamiltonianului interacțiunii Coulombiene permite calcularea valorii medii a energiei a două perechi care formează molecula în dependență de parametrul funcției de undă α , care determină mișcarea relativă a doi magnetoexcitoni în cadrul stării legate. Următoarele calcule numerice vor arăta dacă există starea legată stabilă de tip molecular sau starea legată metastabilă.

The progress in solution of problems involving non-relativistic fast ion-atom collisions with two actively participating electrons has been reviewed. Leading quantum mechanical methods have been analyzed in the framework of four-body scattering theory. A simple formalism has been described on the basis of the Dodd–Greider integral equations for a four-particle system, which were used to analyze the two-electron charge-exchange process at medium and high velocities of relative motion of particles. An important feature of the developed four-particle continuum distorted waves (CDW) method is the consistent preservation of the proper asymptotic limits of the wave functions of a colliding system in the entrance and exit channels of the reaction, which takes into account the long-range nature of Coulomb interactions. The amplitude of the two-electron charge-exchange reaction has been calculated in the approximation of the mechanism of simultaneous capture by an incident particle of two target electrons. The calculations using the presented theory have been made on the example of a two-electron capture reaction in high-energy He2++He collisions.

We consider the question of calculations of the interaction energy of two uniformly charged spheroids. Three cases are realized in the software: the interaction of a uniformly charged spheroid with a point charge; interaction of two coaxial spheroids; and the general case of mutual position of spheroids. The presented programs are initially oriented for nuclear calculations. However, by a change of numerical coefficients, they can be used in the calculations of the interaction energy in any cases of spheroidal objects with the uniformly distributed charge or mass.