In this article we show that the asymptotic iteration method (AIM) allows one to numerically find quasinormal modes of Schwarzschild and de Sitter (SdS) black holes. An added benefit is it can also be used calculate anti-de (SAdS) for case spin zero perturbations. We discuss an improved version AIM, more suitable numerical implementation.

In this paper we use the conformal properties of spinor field to show how can obtain fermion quasinormal modes for a higher-dimensional Schwarzschild black hole. These are interest in so-called split models, where quarks and leptons required exist on different branes order keep proton stable. As has been previously shown, brane-localized fields, larger number dimensions faster hole damping rate. Moreover, also present analytic forms frequencies both large angular momentum mode limits.

Abstract In this article we assess the comprehension of physics concepts by Physical Science and Engineering students enrolled in their first semester at University Johannesburg, South Africa (2022). We employ different graphical measures to explore similarities differences using results both pre- post-test data from force concept inventory assessment tool, which calculate dominant misconceptions (DMs) gains. also use alluvial diagrams track choices made these two groups stages. our...

The method of a conformal transformation is applied to general class single field inflation models with non-minimal coupling gravity and non-standard kinetic terms, in order reduce the cosmological perturbative calculation conventional minimal case all orders perturbation theory. Our analysis made simple by fact that variables comoving gauge are conformally invariant orders. structure vacuum, on which correlation functions evaluated, also discussed. We show how quantization Jordan frame for...

As a continuation of the work by Minamitsuji, Naylor, and Sasaki [J. High Energy Phys. 12 (2006) 079], we discuss Casimir effect for massless bulk scalar field in 4D toy model 6D warped flux compactification model, to stabilize volume modulus. The one-loop effective potential modulus has form similar Coleman-Weinberg potential. stability against quantum corrections is related an appropriate heat kernel coefficient. However, make any physical predictions after stabilization, knowledge...

Abstract This article discusses a three-year study (2020–2022) of dominant misconceptions (DMs) for large cohort first-year physics course students at the University Johannesburg, South Africa. Our considered pre-test scores on force concept inventory using graphical method, where we found statistical differences between mean DM 2020 cohort, as compared to 2021 and 2022 cohort; possibly due onset COVID lockdowns. We also our data from Africa with cohorts based in Spain Kingdom Saudi Arabia,...

In this work we calculate the angular eigenvalues of $(n+4)$-dimensional {\it simply} rotating Kerr-(A)dS spheroidal harmonics using Asymptotic Iteration Method (AIM). We make some comparisons between method and that Continued Fraction (CFM) use latter to check our results. also present analytic expressions for small rotation limit up $O(c^3)$ with coefficient each power $O(\alpha^2)$, where $c=a\omega$ $\alpha=a^2 \Lambda$ ($a$ is velocity, $\omega$ frequency $\Lambda$ cosmological constant).

Using the WKBJ approximation and Unruh method, we obtain semi-analytic expressions for absorption probability (in all energy regimes) Dirac fermions on a higher dimensional Schwarzschild background. We then present an analytic expression relating to cross section, use these results plot emission rates third order in approximation. The setup is sufficiently general such that it could also easily be applied any spherically symmetric background $d$ dimensions. Our lead interesting conclusion...

We investigate some issues regarding quantum corrections for de Sitter branes in a bulk ${\mathrm{AdS}}_{5}$ spacetime. The one-loop effective action Majorana spinor field is evaluated and compared with the scalar result. also evaluate cocycle function various boundary conditions, finding that naturally induce higher order curvature terms original and, general, it not possible to eliminate by renormalization. In one brane limit care must be taken on how extracts physical results. potential...

By finding the spinor eigenvalues for a single deficit angle $(d\ensuremath{-}2)$-sphere, we derive radial potential fermions on $d$-dimensional black hole background that is embedded codimension-two brane with conical singularity, where related to tension. From this obtain quasinormal mode spectrum bulk such background. As by-product of our method, also gives rigorous proof integer spin fields 2-sphere.

In this article we present results for tensor graviton modes (in seven dimensions and greater, $n\ensuremath{\ge}3$) gray-body factors of Kerr--de Sitter black holes Hawking radiation from simply rotating ($n+4$)-dimensional Kerr holes. Although there is some subtlety with defining the temperature a hole, preliminary emissions assuming standard normalization Bousso-Hawking-like normalization.

Based on the work of Chen, L\"u, and Pope, we derive expressions for $D\ensuremath{\ge}6$ dimensional metric Kerr-anti-de Sitter black holes with two independent rotation parameters all others set equal to zero: ${a}_{1}\ensuremath{\ne}0$, ${a}_{2}\ensuremath{\ne}0$, ${a}_{3}={a}_{4}=\ensuremath{\cdots}=0$. The Klein-Gordon equation is then explicitly separated this background. For separation results in a radial coupled generalized spheroidal angular equations. We develop full numerical...

We present a calculation of the zeta function and functional determinant for Laplace-type differential operator, corresponding to scalar field in higher-dimensional de Sitter brane background, which consists anti bulk spacetime bounded by section, representing brane. Contrary existing examples, all make use conformal transformations, we evaluate working directly with wave operator. also consider generic mass term coupling curvature, generalizing previous results. The massless, conformally...

Parametric photon creation via the dynamical Casimir effect (DCE) is evaluated numerically, in a three-dimensional rectangular resonant cavity bisected by semiconductor diaphragm (SD), which irradiated pulsed laser with frequency of GHz order. The aim this paper to determine some optimum conditions required detect DCE photons relevant an experimental detection system. We expand upon thin plasma sheet model [M. Crocce et al., Phys. Rev. A 70, 033811 (2004)] estimate number for both transverse...

The vacuum expectation value of the square field fluctuations a scalar on background consisting two de Sitter branes embedded in an anti-de bulk is considered. We apply dimensional reduction to obtain effective lower space equation motion with associated Kaluza-Klein masses and canonical commutation relations. case obeying restricted class mass curvature couplings, including massless, conformal coupling as special case, find that local behaviour quantum suffers from surface divergences we...

We present numerical results for the particle (photon) creation rate of dynamical Casimir effect (DCE) radiation in a resonant cylindrical microwave cavity. Based on recent experimental proposals, we model an irradiated semiconducting diaphragm (SCD) using time-dependent ``plasma sheet''' where show that number photons created transverse magnetic mode TM${}_{011}$ is considerably enhanced even low laser powers (of $\ensuremath{\mu}$J order). Conversely to moving mirror case, also fundamental...

We look at the question posed by Parker et al. about effect of UV regularisation on power spectrum for inflation. Focusing slow-roll k-inflation, we show that up to second order in Hubble and sound flow parameters, adiabatic such model leads no difference apart from certain cases violate near scale-invariant spectra. Furthermore, extending non-minimal establish equivalence subtraction terms Jordan Einstein frames.

A diagramatic heat kernel expansion technique is presented. The method especially well suited to the small-derivative of kernel, but it can also be used reproduce results obtained by approach known as covariant perturbation theory. new gives an for at coincident points. It obtain derivative and this useful evaluating expectation values stress-energy tensor.

We separate Maxwell's equations for background media that allow both electric and magnetic time-dependence in a generalized Lorenz gauge. In process analogous to the dynamical Casimir effect (DCE) we discuss how surface plasmon polaritons (SPP)s can be created out of vacuum, via time-dependent variation dielectric insulator at metal interface TM TE branches, respectively. suggest extend currently proposed DCE experiments set up detect these excitations. Numerical simulations (without any...