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A three-dimensional slowly rotating black hole solution in the presence of negative cosmological constant in the Einstein-power-Maxwell theory is studied. It is shown that in the small rotation limit the electric field, diagonal metric function and thermodynamic properties in the small rotation limit are the same as for static case, whereas the small rotation gives in addition a non-diagonal metric function and magnetic field which are also small. For these functions cased by rotation of black hole it was obtained exact integral solution and analytic asymptotic solution.

We study charged black hole solutions in 4-dimensional (4D) Einstein-Gauss-Bonnet-Maxwell theory to the linearized perturbation level. We first compute the shear viscosity to entropy density ratio. We then demonstrate how bulk causal structure analysis imposes a upper bound on the Gauss-Bonnet coupling constant in the AdS space. Causality constrains the value of Gauss-Bonnet coupling constant $\alpha_{GB}$ to be bounded by $\alpha_{GB}\leq 0$ as $D\rightarrow 4$., Comment: 13 pages, minor revision, references added

A nonminimal coupling of Weyl curvatures to electromagnetic fields is considered in Brans-Dicke-Maxwell theory. The gravitational field equations are formulated in a Riemannian spacetime where the spacetime torsion is constrained to zero by the method of Lagrange multipliers in the language of exterior differential forms. The significance and ramifications of nonminimal couplings to gravity are examined in a pp-wave spacetime., Koç University

In this chapter, we recapitulate the general properties of the energy momentum tensor (EMT). After the derivation of EMT according to the Noether’s theorem, we will discuss the physical meaning of the components of EMT. Then, we especially focus on the EMT in the gauge theory. The final section is dedicated to EMT in the Maxwell theory as an specific example, which will be helpful for the later chapters, where our studies are discussed.

The book by Father Angelo Secchi, titled in Italian L’Unita delle forze fisiche: Saggio di filosofia naturale, represents a modern approach to physics by looking for a unified view of an enormous variety of different phenomena. While this attempt is a common path for many researchers nowadays, in Secchi’s time it was a modern, somewhat revolutionary viewpoint. In a period marked by an increasingly “analytical” approach to science, thanks in part to the development of efficient modern mathematical tools, Secchi decided to adopt for epistemological reasons a “synthetic,” comprehensive view. In this short note, I will describe how this attempt was developed by Secchi in his book, which was published in 1864 and marked, along with Le Stelle and Le Soleil, the first of his three main books.

In a series of recent works based on foliation-based quantization in which renormalizability has been achieved for the physical sector of the theory, we have shown that the use of the standard graviton propagator interferes, due to the presence of the trace mode, with the four-dimensional covariance. A subtlety in the background field method also requires careful handling. This status of the matter motivated us to revisit an Einstein-scalar system in one of the sequels. Continuing the endeavors, we revisit the one-loop renormalization of an Einstein–Maxwell system in the present work. The systematic renormalization of the cosmological and Newton constants is carried out by applying the refined background field method. The one-loop beta function of the vector coupling constant is explicitly computed and compared with the literature. The longstanding problem of the gauge choice dependence of the effective action is addressed, and the manner in which gauge choice independence is restored in the present framework is discussed. The formalism also sheds light on background independent analysis. The renormalization involves a metric field redefinition originally introduced by ’t Hooft; with the field redefinition the theory should be predictive.

The evident seasonality of influenza suggests a significant role for weather and climate as one of several determinants of viral respiratory disease (VRD), including social determinants which play a major role in shaping these phenomena. Based on the current mechanistic understanding of how VRDs are transmitted by small droplets, we identify an environmental variable, Air Drying Capacity (ADC), as an atmospheric state-variable with significant and direct relevance to the transmission of VRD. ADC dictates the evolution and fate of droplets under given temperature and humidity conditions. The definition of this variable is rooted in the Maxwell theory of droplet evolution via coupled heat and mass transfer between droplets and the surrounding environment. We present the climatology of ADC, and compare its observed distribution in space and time to the observed prevalence of influenza and COVID-19 from extensive global data sets. Globally, large ADC values appear to significantly constrain the observed transmission and spread of VRD, consistent with the significant coherency of the observed seasonal cycles of ADC and influenza. Our results introduce a new environmental determinant, rooted in the mechanism of VRD transmission, with potential implications for explaining seasonality of influenza, and for describing how environmental conditions may impact to some degree the evolution of similar VRDs, such as COVID-19.

The full Standard-Model Extension contains operators of arbitrary mass dimension. The recent classification of these operators for gauge theories has substantially broadened the avenue for phenomenological explorations of Lorentz symmetry in electrodynamics. This work focuses on the cubic mass-dimension six contribution to pure Maxwell theory. Its effects on the propagation of light in an external magnetic field are discussed, and the prospects of determining experimental constraints are assessed.

We use the classical double copy to identify a necessary condition for Maxwell theory sources to constitute single copies of Kerr-Schild solutions to Einstein's equations. In the case of four-dimensional Kerr-Schild spacetimes on Minkowski backgrounds, we extend this condition to a parameterization of the corresponding single copies. These are given by Li\'enard-Wiechert fields of charges on complex worldlines. This unifies the known instances of the Kerr-Schild double copy black holes on flat four-dimensional backgrounds into a single framework. Furthermore, we use the more generic condition identified to show why the black ring in five dimensions does not admit Kerr-Schild coordinates., Comment: To be published in JHEP. Version updated in include clarifications in wording, new sentences making a few additional remarks, and typo corrections

The most common physical formalisms are the Lagrangian formalism and the Hamiltonian formalism. From the superficial point of view, they are one and the same, but rewritten in other terms. However, it seems that the Hamiltonian formalism has a richer structure and is more convenient for studying the electromagnetic field, especially in the formalization of its geometrization. Unfortunately for field problems, there is a whole set of Hamiltonian formalisms. The authors study the applicability of different variants of the Hamiltonian formalism to the problems of electrodynamics. In this paper we consider the Hamiltonian formalism with constraints., Comment: in English; in Russian

Using the Wald formalism, we investigate the thermodynamics of charged black holes in D-dimensional stationary spacetimes with or without rotations in Einstein-\ae ther-Maxwell theory. In particular, assuming the existence of a scaling symmetry of the action, we obtain the Smarr integral formula, which can be applied to both Killing and universal horizons. When restricted to 4-dimensional spherically symmetric spacetimes, previous results obtained by a different method are re-derived., Comment: No figures and tables. Phys. Let. B782 (2018) 723-727

In this paper, we will consider cosmological implications of the Maxwell theory coupled to a non-local $U(1)$-symmetric term. It is well-known that the theory in flat space time, reduces to the Proca theory. However, it will be shown that in curved space time the resulting theory will differ from the coupled Einstein-Proca system. The cosmological perturbations on top of the de Sitter space-time is also considered and the dynamics of separate modes will be investigated in detail. Anisotropic cosmology of the model is also investigated and we will show that the behavior of the universe at late time satisfies the observational data and the model predicts an isotropic universe., 10 pages, 2 figures

In this work, the magnetic and magnetocaloric properties of 0.5La 0.7 Ca 0.2 Sr 0.1 MnO 3 /0.5La 0.7 Te 0.3 MnO 3 composite have been investigated. The 0.5La 0.7 Ca 0.2 Sr 0.1 MnO 3 /0.5La 0.7 Te 0.3 MnO 3 composite has been composed by mixing the La 0.7 Ca 0.2 Sr 0.1 MnO 3 and La 0.7 Te 0.3 MnO 3 manganites with a ratio of 0.5:0.5, synthesized by using the standard solid state method. In order to investigate the magnetic and magnetocaloric properties of the samples, magnetization measurements dependence on temperature and magnetic field have been performed by using physical property measurement system. The nature of the magnetic phase transition for all materials has been identified by using Banerjee criterion and Landau theory and according to both methods the magnetic phase transition is second order. Magnetic entropy change values have been calculated by using Maxwell relation and Landau theory. Based on Maxwell relation, the maximum magnetic entropy change value of the composite has been calculated as 3.70 Jkg -1 K -1 for 5 T.

We describe a non-minimal higher-derivative extension of Einstein–Maxwell theory in which electrically-charged black holes and point charges have globally regular gravitational and electromagnetic fields. We provide an exact static, spherically symmetric solution of this theory that reduces to the Reissner–Nordström one at weak coupling, but in which the singularity at r = 0 is regularized for arbitrary mass and (non-vanishing) charge. We discuss the properties of these solutions and comment on the physical significance of our results.

In this paper, we have studied the Maxwell radiation from the electron orbiting the nucleus in an atom such as hydrogen atom. The orbiting electron is thought as two oscillating dipoles: one on [Formula: see text]-axis and the other on [Formula: see text]-axis with the same frequency. We have derived the electromagnetic wave and calculated powers of the radiation from these two oscillating dipoles, and then determined the time period it takes for the electron to change its energy levels from [Formula: see text] to [Formula: see text] due to the Maxwell radiation. Compared the time period due to the Maxwell radiation with the time period from the uncertainty principle, it is found that the two time periods are different from each other by about nine orders of magnitude. So, we are led to believe that the Maxwell theory could not be used in the quantum photo emission by the electron in an atom. Thus, we suggest that the quantum photo emission by the electron in an atom may be photon tunneling from the electron [Formula: see text] in an atom.

Electromagnetism plays an essential role, both in basic and applied physics research [...]