The role of photon polarization modes in the magnetization and instability of the vacuum in a supercritical field

The response of the QED vacuum in an asymptotically large electromagnetic field is studied. In this regime the vacuum energy is strongly influenced by the vacuum polarization effect. The possible interaction between the virtual electromagnetic radiation and a superstrong magnetic field suggests that a background of virtual photons is a source of magnetization to the whole vacuum. The corresponding contribution to the vacuum magnetization density is determined by considering the individual contribution of each vacuum polarization eigenmode in the Euler-Heisenberg Lagrangian. Additional issues concerning the transverse pressures are analyzed. We also study the case in which the vacuum is occupied by a superstrong electric field. It is discussed that, in addition to the electron-positron pairs, the vacuum could create photons with different propagation modes. The possible relation between the emission of photons and the birefringent character of the vacuum is shown as well.Comment: 7 pages, 2 figures, accepted in Phys.Lett.

QED with external field: Hamiltonian treatment for anisotropic medium formed by the Lorentz-non-invariant vacuum

Nonlinear electrodynamics, QED included, is considered against the Lorentz-noninvariant external field background, treated as an anisotropic medium. Hamiltonian formalism is applied to electromagnetic excitations over the background, and entities of electrodynamics of media, such as field inductions and intensities, are made sense of in terms of canonical variables. Both conserved and nonconserved generators of space-time translations and rotations are defined on the phase space, and their Hamiltonian equations of motion and Dirac bracket relations, different from the Poincar\'e algebra, are established. Nonsymmetric, but--in return--gauge-invariant, energy-momentum tensor suggests a canonical momentum density other than the Poynting vector. A photon magnetic moment is found to govern the evolution of the photon angular momentum. It is determined by the antisymmetric part of the energy-momentum tensor.Comment: 28 page

Algorithmic derivation of Dyson-Schwinger Equations

We present an algorithm for the derivation of Dyson-Schwinger equations of general theories that is suitable for an implementation within a symbolic programming language. Moreover, we introduce the Mathematica package DoDSE which provides such an implementation. It derives the Dyson-Schwinger equations graphically once the interactions of the theory are specified. A few examples for the application of both the algorithm and the DoDSE package are provided. The package can be obtained from physik.uni-graz.at/~mah/DoDSE.html.Comment: 17 pages, 11 figures, downloadable Mathematica package v2: adapted to version 1.2 of DoDSE package with simplified handling and improved plotting of graphs; references adde

The Impact of E-Recruitment and Artificial Intelligence (AI) Tools on HR Effectiveness: The Case of High Schools

The HRM encompasses a broad variety of topics, including preparation, recruiting, workforce relations and organisational growth. The people in any organisation are a wealth of information and experience. Acquisition of certain workers by recruiting thus plays a major role today. The implementation method for e-recruitment practices is the reason behind the success of organisational performance. The recruiting method used to be longer and entailed a great deal of paperwork for recruiters, but it began evolving steadily as online recruitment became more widespread. In recent years, a study has been carried out on integrating these two essential facets of HRM and technology due to technical developments. Studies are typically carried out about how technologies will render the hiring phase easier and optimised. The research implemented a mixed approach methodology throughout conducting interviews and questionnaires over a defined number of respondents in High Schools. The survey had been distributed using google forms, and the interviews had been conducted through zoom meeting due to the COVID-19 Pandemic. The results proved a direct relationship between the implementation of e-recruitment in School and employee performance

The Impact of Teaching Innovative Strategy on Academic Performance in High Schools

The study focuses primarily on the impact of creative teaching on learning effectiveness in a certain technical vocational school in Vietnam. The satisfaction in the learning of students is like a variable mediator. The sample population of the research was the student organ of the technical-professional college in Taiwan. Comfort samples were included for taking the samples. To validate the whole study model and to calculate its success fit, the structural model. Analysis showed that the direct and optimistic impact of creativity in teaching on student quality was insignificant. Secondly, there is a strong positive effect on the enjoyment of learning from innovation. The satisfaction of the learners affects their academic success significantly and explicitly. In short, student satisfaction is as mediating as possible between learning and schools. It will also improve students comprehension and progress. Thus, this study has attempted to monitor and acknowledge the effect of learning creativity on learning performance in vocational, technical, and schools in Taiwan – with the mediation variable being learning satisfaction

The Impact of Educational Marketing on Universities Performance

This paper addresses the results of the various publicity strategies undertaken by selected private management organizations in Vietnam. The study has also investigated the activities of students from BBA and MBA who have been hired by their management college both at home and abroad. The development model for this study comprises with 7ps of a marketing blend designed for schools. 342 students from 9 colleges received self-administered questionnaires. For the analysis of the findings obtained, descriptive figures were used. The study of available information found that the best consideration for BBA and MBA was suggested by mates. Word of mouth, i.e. guidance from friends and relatives, colleges and newspaper ads, has also proved popular. The BBA demand for registration was too heavy, although at the MBA level profiles and teaching methods were high on the agenda, as were the opportunities for future employment and better work. Students, non-school event schemes and library facilities were the subject of the results. The study findings show that a universitys reputation lies deeply in its ability to meet stakeholder expectations; in the present extremely competitive environment, brand credibility management can be considered an important issue for most universities.The research results may be helpful in favor of instructional programs for administrators that create the strategies to encourage success in a university. We conclude that the results of this study clarify the psychology of the students and create adequate outreach campaigns for all colleges, advertising organizations and government departments. It will also help supervise those activities to better respond to the needs of students and service providers and make it more attractive for all potential students in private colleges

Non-perturbative Euler-Heisenberg Lagrangian and Paraelectricity in Magnetized Massless QED

In this paper we calculate the non-perturbative Euler-Heisenberg Lagrangian for massless QED in a strong magnetic field $H$, where the breaking of the chiral symmetry is dynamically catalyzed by the external magnetic field via the formation of an electro-positron condensate. This chiral condensate leads to the generation of dynamical parameters that have to be found as solutions of non-perturbative Schwinger-Dyson equations. Since the electron-positron pairing mechanism leading to the breaking of the chiral symmetry is mainly dominated by the contributions from the infrared region of momenta much smaller than $\sqrt{eH}$, the magnetic field introduces a dynamical ultraviolet cutoff in the theory that also enters in the non-perturbative Euler-Heisenberg action. Using this action, we show that the system exhibits a significant paraelectricity in the direction parallel to the magnetic field. The nonperturbative nature of this effect is reflected in the non-analytic dependence of the obtained electric susceptibility on the fine-structure constant. The strong paraelectricity in the field direction is linked to the orientation of the electric dipole moments of the pairs that form the chiral condensate. The large electric susceptibility can be used to detect the realization of the magnetic catalysis of chiral symmetry breaking in physical systems.Comment: 18 pages, to be published in NP

Don Lupe Oro C2020: nueva variedad de trigo duro para el noroeste de México

El noroeste de México es la principal región productora de trigo cristalino (Triticum durum Desf.). Durante el año 2020 se cultivaron 159,229 ha con este tipo de trigo, las cuales representaron el 90.5 % de la superficie total sembrada en México. Dicha región alcanzó una producción de 1.19 millones de toneladas, con un valor de la producción de 5.25 mil millones de pesos (SIAP, 2021)

Electron-seeded ALP production and ALP decay in an oscillating electromagnetic field

Certain models involving ALPs (axion-like-particles) allow for the coupling of scalars and pseudoscalars to fermions. A derivation of the total rate for production of massive scalars and pseudoscalars by an electron in a monochromatic, circularly-polarised electromagnetic background is presented. In addition, a derivation and the total rate for the decay of massive scalars and pseudoscalars into electron-positron pairs in the same electromagnetic background is given. We conclude by approximating the total yield of ALP production for a typical laser-particle experimental scenario.Comment: 7 pages, 4 figure