Cylindrical Spacetime Research Articles

Charged Nariai black holes on the dark bubble

Abstract In this paper, we realise the charged Nariai black hole on a braneworld from a
nucleated bubble in AdS5, known as the dark bubble model. Geometrically, the black hole
takes the form of a cylindrical spacetime pulling on the dark bubble. This is realised by a
brane embedding in an AdS5 black string background. Identifying the brane with a D3-brane
in string theory allows us to determine a relation between the fine structure constant and the
string coupling, αEM = 3 gs/2, which was previously obtained for a microscopic black hole. We
also speculate on the consequences for the Festina Lente bound and neutrino masses.

Mach’s principle-based model of the origin of mass

In this paper, we present a Mach’s principle-based model of the origin of mass. According to Mach’s principle, the mass of matter arises from the coupling with the rest of the Universe rather than being an inherent property of matter itself. This model, in a sense, provides a model realization of Mach’s principle. In this model, the mass of matter is determined by spacetime. We illustrate the model by solving exact solutions in various spacetimes, such as static spherical, Robertson-Walker, and static cylindrical spacetimes.

The general expression for [formula omitted] in a charged cylindrical spacetime with diverse dimensions

By utilizing the field equations of the modified teleparallel equivalent of general relativity, denoted as f(T), we obtain an exact solution for a static charged black hole in n-dimensions, without imposing any constraints. The black hole possesses two distinctive dimensional constants: m and v with unit length. The first constant is associated with the mass, while the second constant represents the electric charge. The presence of this electric charge leads the black hole to deviate from the predictions of the teleparallel equivalent of general relativity (TEGR). We show that f(T) depends on the constant v and becomes a constant function when v is set to zero. An intriguing feature of this black hole is its lack of singularities in the invariants built from torsion and curvature when the dimension n lies within the range of 4≤n≤6 as r→0. However, for n≥7, the singularity becomes milder in comparison to the case in the teleparallel equivalent of general relativity (TEGR). Furthermore, we compute the energy of this solution using the conserved n-momentum vector and establish its equivalence to the ADM mass, up to O(1r). Otherwise, we observe higher-order contributions arising from the electric charge terms. By performing a coordinate transformation on the black hole, we obtain an exact solution for a stationary rotating black hole, which exhibits non-trivial values of the torsion scalar and the analytic function f(T). In order to gain insight into the physics of this black hole, we calculate various physical quantities related to thermodynamics, such as entropy, Hawking temperature, and heat capacity. The analysis reveals that the black hole exhibits thermal stability.

Quantum Chern–Simons Theories on Cylinders: BV-BFV Partition Functions

We compute partition functions of Chern–Simons type theories for cylindrical spacetimes I times Sigma , with I an interval and dim Sigma = 4l+2, in the BV-BFV formalism (a refinement of the Batalin–Vilkovisky formalism adapted to manifolds with boundary and cutting–gluing). The case dim Sigma = 0 is considered as a toy example. We show that one can identify—for certain choices of residual fields—the “physical part” (restriction to degree zero fields) of the BV-BFV effective action with the Hamilton–Jacobi action computed in the companion paper (Cattaneo et al., Constrained systems, generalized Hamilton–Jacobi actions, and quantization, arXiv:2012.13270), without any quantum corrections. This Hamilton–Jacobi action is the action functional of a conformal field theory on Sigma . For dim Sigma = 2, this implies a version of the CS-WZW correspondence. For dim Sigma = 6, using a particular polarization on one end of the cylinder, the Chern–Simons partition function is related to Kodaira–Spencer gravity (a.k.a. BCOV theory); this provides a BV-BFV quantum perspective on the semiclassical result by Gerasimov and Shatashvili.

Gravastars with cylindrical space–time in f(G, T) gravity

Gravastars with cylindrical space–time in f(G, T) gravity

Note on the Levi-Civita metric

By introducing a new coordinate condition we divide the cylindrical spacetime of Levi-Civita (LC) into a sourceful inner ([Formula: see text]) and vacuum outer ([Formula: see text]) regions. The emergent fluid with zero radial pressure confined to the finely-tuned inner region serves to make the spacetime regular in a natural way. At [Formula: see text] the LC spacetime becomes ‘Cartesian flat’ so that no deficit angle arises.

Spatio-temporal clustering analysis using two different scanning windows: A case study of dengue fever in Peninsular Malaysia

Dengue fever is a mosquito-borne viral infection of humans caused by a virus of the Flaviviridae family. In Malaysia the annual incidence risk of dengue fever for the period 2000 to 2019 ranged from 30 to 390 cases per 100,000. The aim of this paper was to identify spatial, temporal and spatio-temporal clusters of dengue fever in Peninsular Malaysia for the period 2015 to 2017.Counts of confirmed incident cases of dengue fever for each of the 86 districts of Peninsular Malaysia for the period 1 January 2015 to 31 December 2017 (inclusive) and district-level census data allowed us to calculate the incidence rate of dengue fever, defined as the number of confirmed cases of dengue fever per 100,000 person-years at risk. We applied Kulldorff’s cylindrical space–time scan statistic and Takahashi et al.’s prismatic space–time scan statistic to the data.We identified no major differences in the number and location of spatial clusters of dengue incidence for 2015, 2016 and 2017 using Kulldorff’s and Takahashi et al.’s method. Spatio-temporal clusters of dengue occurred at several times throughout each year in various high population dense areas. These clusters not only included high population density districts but also their adjacent district neighbours. The temporal clustering of dengue cases during the monsoon season (mid September to late December each year) implies that there is a biologically plausible causal association between rainfall and the incidence of dengue.Identification of locations and time periods when the frequency of dengue is high allows Malaysian public health authorities to be more objective in their decision making around vector control and dengue public awareness campaigns. Future research will quantify the association between population density and rainfall on dengue incidence. This will allow health authorities to take a more proactive approach for dengue control.

Electromagnetic effects on cylindrical gravastar-like strings in f(R, T, RσηTση) gravity

The purpose of this paper is to investigate the non-singular solutions of gravitationally vacuumed condensate star in the realm of the f(R, T, Q) theory, where Q = RσηTση. The three-layered gravastar structure has been constructed in the cylindrical spacetime under the effects of electromagnetism in the modified theory. Furthermore, we have studied the effects of electromagnetism on the effective matter, which involves the perfect fluid and isotropic pressure in it. To gain this objective, we consider the cylindrical spacetime and evaluate the three regions mathematically. The metric coefficients are calculated independently for each region. To match the region I and II at a hypersurface, the junction conditions have been calculated. To figure out the dependency of the thickness of shell on different physical features of gravastar, we interpret it graphically as well as mathematically. Subsequently, the noticeable facts are accomplished.

Boundary regularity for parabolic systems in convex domains

In a cylindrical space–time domain with a convex, spatial base, we establish a local Lipschitz estimate for weak solutions to parabolic systems with Uhlenbeck structure up to the lateral boundary, provided homogeneous Dirichlet data are assumed on that part of the lateral boundary.

Study of stellar structures in f(ℛ,𝒯μν𝒯μν) theory

This paper deals with the dynamics of cylindrical collapse with anisotropic fluid distribution in the framework of [Formula: see text] gravity. For this purpose, we consider non-static and static cylindrical spacetimes in the inner and outer regions of a star, respectively. To match both geometries at the hypersurface, we consider the Darmois junction conditions. We use the Misner–Sharp technique to examine the impacts of correction terms and effective fluid parameters on the dynamics of a cylindrical star. A correlation between the Weyl tensor and physical quantities is also developed. The conformally flat condition is not obtained due to the influence of anisotropic pressure and higher-order nonlinear terms. Further, we assume isotropic fluid and specific model of this theory which yields the conformally flat spacetime and inhomogeneous energy density. We conclude that the collapse rate reduces as compared to general relativity due to the inclusion of effective pressure and additional terms of this theory.

Notes from the bulk: Metric dependence of the edge states of Chern-Simons theory

The Abelian Chern-Simons theory is considered on a cylindrical spacetime $\mathbb{R}\ifmmode\times\else\texttimes\fi{}D$, in a not necessarily flat Lorentzian background. As in the flat bulk case with planar boundary, we find that also on the radial boundary of a curved background a Ka\ifmmode \mbox{\c{c}}\else \c{c}\fi{}-Moody algebra exists, with the same central charge as in the flat case, which henceforth depends neither on the bulk metric nor on the geometry of the boundary. The holographically induced theory on the 2D boundary is topologically protected, in the sense that it describes a Luttinger liquid, no matter which the bulk metric is. The main result of this paper is that a remnant of the 3D bulk theory resides in the chiral velocity of the edge modes, which is not a constant like in the flat bulk case, but it is local, depending on the determinant of the induced metric on the boundary. This result may provide a theoretical framework for the recently observed accelerated chiral bosons on the edge of some Hall systems.

Analysis of a charged unidirectional perfect fluid gravitational collapse in cylindrical spacetime

The gravitational collapse of charged imperfect fluids (including the presence of strings) models the structural evolution of the Universe. The dynamics of a charged cylindrically symmetric spacetime investigates the effects of charge on the rate of gravitational collapse. In this respect, the Einstein–Maxwell equations are formed and solved to obtain the values of the dynamical parameters of the fluid including density, pressure and electric field. These parameters are graphically presented. It was concluded that the string tension effects all the physical parameters of the fluid. Moreover, the density and electric field intensity increases while the fluid’s pressure decreases near the time of singularity formation.

Carleman estimates with sharp weights and boundary observability for wave operators with critically singular potentials

We establish a new family of Carleman inequalities for wave operators on cylindrical spacetime domains involving a potential that is critically singular, diverging as an inverse square on all the boundary of the domain. These estimates are sharp in the sense that they capture both the natural boundary conditions and the natural $H^1$-energy. The proof is based around three key ingredients: the choice of a novel Carleman weight with rather singular derivatives on the boundary, a generalization of the classical Morawetz inequality that allows for inverse-square singularities, and the systematic use of derivative operations adapted to the potential. As an application of these estimates, we prove a boundary observability property for the associated wave equations.

New cylindrically symmetric solution of Einstein field equations their conservation laws and the particles dynamics

The study explores the particle dynamics, asymptotic behavior, and flatness in Riemann curvature corresponding to the solutions obtained from the Ricci tensor of cylindrical spacetimes. Since these solutions are non-Minkowskian and are proposed to have curvature in almost all the cases, that is why some cylindrically symmetric static vacuum solutions of Einstein Field Equations have been worked out. We explore the Noether symmetries along with their conservation laws of the corresponding static-spacetime and calculate the equation of motions by taking into account Noether symmetries. We study the dynamics of particle in the form of effective potential, effective force.

Cylindrical spacetimes due to radial magnetic fields

We continue our previous study of cylindrically symmetric, static electrovacuum spacetimes generated by a magnetic field, involving optionally the cosmological constant, and investigate several classes of exact solutions. These spacetimes are due to magnetic fields that are perpendicular to the axis of symmetry.

New definition of complexity factor in f(R,T,RμνTμν) gravity

This paper is devoted to present new definition of complexity factor for static cylindrically symmetric matter configurations in $f(R,T,R_{\mu\nu}T^{\mu\nu})$ gravity. For this purpose, we have considered irrotational static cylindrical spacetime coupled with a locally anisotropic relativistic fluid. After formulating gravitational field and conservation equations, we have performed orthogonal splitting of the Riemann curvature tensor. Unlike GR (for spherical case) the one of the structure scalars $X_{TF}$, has been identified to be a complexity factor. This factor contains effective forms of the energy density, and anisotropic pressure components. Few peculiar relations among complexity factor, Tolman mass and Weyl scalar are also analyzed with the modified $f(R,T,R_{\mu\nu}T^{\mu\nu})$ corrections.

Simultaneity in cylindrical spacetime

In cylindrical spacetime which is flat like Minkowski spacetime but is spatially closed, two twins can part and reunite, while none of them go through any acceleration. Still, the twins are aged differently upon their reunion (except for some special occasions). The key to understanding what happens in cylindrical spacetime lies in clock synchrony. In cylindrical spacetime, the Round-trip Axiom (that two light signals sent simultaneously in opposite directions along a closed path return simultaneously) fails to hold, and so distant clocks cannot be consistently synchronized following the standard procedure proposed by Einstein except for those under some privileged motion. We propose an alternative method of synchrony utilizing the one-way speed of light traveling around the universe, which can be measured with one clock and varies from inertial frame to inertial frame. This alternative synchrony renders simultaneity not relative but absolute and makes it possible to consistently describe both the local and global phenomena in cylindrical spacetime.

Charged gravastars with cylindrical spacetime

The objective of this work is to construct a gravastar model using thin-shell formalism and discuss its realistically accepted properties with the background of cylindrical metric. In this scenario, we matched the interior cylindrical geometry with exterior metric via Israel matching conditions. The stability of the constructed model under the influence of electric charge is then examined using linear perturbations around the equilibrium condition. We explored some stable regimes near the equilibrium condition with different values of charge as well as involved parameters.

Locally isotropic gravastars with cylindrical spacetime

This paper is aimed to set up a thin-shell gravastar model and address its physically accepted features in the background of noncommutative geometry. For this purpose, we have considered the cylindrically symmetric interior metric matched with suitable noncommutative exterior geometry using Israel boundary conditions. The stability of this thin-shell as well as thermodynamical stability is then explored under linear perturbations around the throat. We have found the stable regions near the horizon with some specific values of the involved parameters.

Anomalous magnetic moment and vortex structure of the electron

The electron magnetic moment decomposition calculated in QED is proposed to have origin in a multi-vortex internal structure of the electron. This proposition is founded on two important contributions of this work. First, a critical review on Weyl model of electron, Einstein–Rosen bridge and Wheeler’s wormholes leads to a new idea of a topological defect in cylindrical spacetime geometry as a natural representation of the electron. A concrete realization of this idea in terms of the derivation of a new vortex-metric, and its physical interpretation to establish the geometric origin of the electron magnetic moment decomposition constitute the second contribution. Remarkable occurrence of a vortex structure in the basis mode function used in BLFQ is also pointed out indicating wider ramification of the proposed electron model.