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Tourmaline (TM) has received extensive interest in the purification field due to its unique spontaneous polarization. In this paper, the effects of three sizes of purified TM samples on the air filters were studied. The electrode performance of TM samples was investigated using piezoelectric and pyro‐electric experiments. The results show an electrode from the 0.074 mm separated TM had the superior property. Three types of TM powders with the highest B2O3% content were adhered to the filter to evaluate the filtration performance. Elbaite 0.074 mm with 9.34 B2O3% content had the optimal filtration efficiency when the pressure drop increased slightly. The Rietveld method was used to refine the samples X‐Ray diffraction patterns to obtain the crystal structure. The electrostatic adsorption caused by the TM spontaneous polarization contributes to improving the filtration property of the filter materials. [ABSTRACT FROM AUTHOR]

One of the alternatives to the Standard Model (SM) of elementary particles is the supersymmetry theories; the electric dipole moment (EDM) of elementary particles can serve as an excellent tool to confirm the validity of one of these models. For example: in the case of a neutron, the EDM, compatible with the SM, is within a range of to e cm, whereas the supersymmetry theories predict the presence of an EDM of much larger value, at the level of – e cm. Experiments on the search for EDM have been carried out for more than 50 years; however, most of them are based on charge-neutral particles (neutron, atoms). The EDM of charged particles (proton, deuteron) can be measured in a storage ring with the use of the phenomenon of the beam polarization precession in an electromagnetic field. The storage ring has a number of advantages when used as a tool for EDM measurement; however, there are also a number of problems. This paper discusses the main approaches to solving these problems: the BNL, spin wheel, and frequency domain methods. [ABSTRACT FROM AUTHOR]

Decreasing of layer thickness causes the decrease of polarization until it disappears due to the existence of depolarization field. Therefore, the search for strong piezoelectric materials is highly desirable for multifunctional ultra-thin piezoelectric devices. Herein, we propose a common strategy for achieving strong piezoelectric materials through the electronic asymmetry induced by the intrinsically asymmetric atomic character of different chalcogen atoms. Accordingly, in the tetrahedral lattice structures, for example, M4X3Y3 (M = Pd/Ni, X/Y = S, Se or Te, X ≠ Y) monolayers are proved to display excellent out-of-plane piezoelectricity. Ni4Se3Te3 possesses the largest piezoelectric coefficient d33 of 61.57 pm/V, which is much larger than that of most 2D materials. Enhancing the electronic asymmetry further increases the out-of-plane piezoelectricity of Janus M4X3Y3 materials. Correspondingly, the out-of-plane piezoelectricity is positively correlated with the ratio of electronegativity difference (Red) and the electric dipole moment (P). This work provides alternative materials for energy harvesting nano-devices or self-energized wearable devices, and supplies a valuable guideline for predicting 2D materials with strong out-of-plane piezoelectricity. [ABSTRACT FROM AUTHOR]

In the search for clues to the matter–antimatter puzzle, experiments with atoms or molecules play a particular role. These systems allow measurements with very high precision, as demonstrated by the unprecedented limits down to 10−30 e cm on electron EDM using molecular ions, and relative measurements at the level of 10−12 in spectroscopy of antihydrogen atoms. Building on these impressive measurements, new experimental directions offer potential for drastic improvements. We review here some of the new perspectives in those fields and their associated prospects for new physics searches. This article is part of the theme issue 'The particle-gravity frontier'. [ABSTRACT FROM AUTHOR]

Detecting a non-zero electric dipole moment in a particle would unambiguously signify physics beyond the Standard Model. A potential pathway towards this is the detection of a nuclear Schiff moment, the magnitude of which is enhanced by the presence of nuclear octupole deformation. However, due to the low production rate of isotopes featuring such 'pear-shaped' nuclei, capturing, detecting and manipulating them efficiently is a crucial prerequisite. Incorporating them into synthetic diamond optical crystals can produce defects with defined, molecule-like structures and isolated electronic states within the diamond band gap, increasing capture efficiency, enabling repeated probing of even a single atom and producing narrow optical linewidths. In this study, we used density functional theory to investigate the formation, structure and electronic properties of crystal defects in diamond containing 229Pa , a rare isotope that is predicted to have an exceptionally strong nuclear octupole deformation. In addition, we identified and studied stable lanthanide-containing defects with similar electronic structures as non-radioactive proxies to aid in experimental methods. Our findings hold promise for the existence of such defects and can contribute to the development of a quantum information processing-inspired toolbox of techniques for studying rare isotopes. This article is part of the Theo Murphy meeting issue 'Diamond for quantum applications'. [ABSTRACT FROM AUTHOR]

Atomic partial charges cannot be physically measured but they play a significant role in many chemical theories and theoretical models. Therefore, they are, evaluated from experimentally acquired properties or calculated by quantum chemistry computational methods. This study is focused on determining chemical accuracy of various theoretical methods of computing atomic partial charges based on quantum chemistry. Values of gas-phase atomic partial charges were acquired by Mulliken (MUL) population analysis, natural bond analysis (NBO), Merz-Singh-Kollman (MSK) scheme, and atomic polar tensor (APT) charges computed considering Density Functional Theory and ab initio Møller-Plesset up to the second order levels. Correlations between the calculated values were determined by principal component analysis (PCA) and further confirmed by linear regression. The best agreement between experimentally evaluated atomic partial charges and theoretical values was obtained with the MSK scheme. [ABSTRACT FROM AUTHOR]

The He–McKellar–Wilkens (HMW) effect in noncommutative space has been explored through two distinct methodologies. One approach treats the neutral particle, which harbors a permanent electric dipole moment, as an unstructured entity, while the other approach considers the neutral particle as a composite system consisting of a pair of oppositely charged particles. To preserve gauge symmetry, we apply the Seiberg–Witten map. Surprisingly, both of these approaches converge on the same result. They independently confirm that, up to the first order of the noncommutative parameter (NCP), no corrections are observed in the phase of the HMW effect. Remarkably, these two approaches, although founded on fundamentally different mechanisms, yield identical conclusions. [ABSTRACT FROM AUTHOR]

Electroweak baryogenesis can be driven by the top quark in a general two Higgs doublet model with extra Yukawa couplings. Higgs quartics provide the first order phase transition, while extra top Yukawa coupling ρ t t can fuel the cosmic baryon asymmetry through the λ t Im ρ t t product, with flavor-changing ρ t c coupling as backup. The impressive ACME 2018 bound on the electron electric dipole moment calls for an extra electron coupling ρ e e for exquisite cancellation among dangerous diagrams, broadening the baryogenesis solution space. The mechanism suggests that extra Yukawa couplings echo the hierarchical structure of standard Yukawa couplings. Phenomenological consequences in the Higgs search and flavor physics are discussed, with μ and τ EDM touched upon. [ABSTRACT FROM AUTHOR]

Based on fundamental symmetries, molecules cannot have a permanent electric dipole moment, although it is commonly used in the literature to explain the different molecular spectra for heteronuclear and homonuclear molecules. Electric-dipole rotational and vibrational spectra can indeed be observed in heteronuclear molecules, while they are missing in molecules with identical nuclei. This paper shows that the missing spectral features can be explained as an effect of the exchange symmetry for identical particles.