Modern Physics Letters A

The Casimir effect for mass dimension one fermion fields (sometimes called Elko) in (3 + 1) dimensions is obtained using Dirichlet boundary conditions. It is shown that the existence of a repulsive force is four times greater than the case of the scalar field. The precise reason for such differences are highlighted and interpreted, as well as the right parallel of the Casimir effect due to scalar and fermionic fields.

The theoretical basis for the energy carried away by gravitational waves that an isolated gravitating system emits was first formulated by Hermann Bondi during the ’60s. Recent findings from the observation of distant supernovae revealed that the rate of expansion of our universe is accelerating, which may be well explained by sticking a positive cosmological constant into the Einstein field equations for general relativity. By solving the Newman–Penrose equations (which are equivalent to the Einstein field equations), we generalize this notion of Bondi mass–energy and thereby provide a firm theoretical description of how an isolated gravitating system loses energy as it radiates gravitational waves, in a universe that expands at an accelerated rate. This is in line with the observational front of LIGO’s first announcement in February 2016 that gravitational waves from the merger of a binary black hole system have been detected.

In this paper, the implications of considering interaction between Chaplygin gas and a barotropic fluid with constant equation of state have been explored. The unique feature of this work is that assuming an interaction $Q\propto H{\rho }_d$, analytic expressions for the energy density and pressure have been derived in terms of the hypergeometric ${}_2{\text{F}}_1$ function. It is worthwhile to mention that an interacting Chaplygin gas model was considered in 2006 by Zhang and Zhu, nevertheless, analytic solutions for the continuity equations could not be determined assuming an interaction proportional to $H$ times the sum of the energy densities of Chaplygin gas and dust. Our model can successfully explain the transition from the early decelerating phase to the present phase of cosmic acceleration. Arbitrary choice of the free parameters of our model through trial and error shows that recent observational data strongly favors $w_m=0$ and $w_m=-\frac{1}{3}$ over the $w_m=\frac{1}{3}$ case. Interestingly, the present model also incorporates the transition of dark energy into the phantom domain, however, future deceleration is forbidden.

We consider the problem of determination of a volume of some bounded space-like hypersurfaces in the case of spherically symmetric spacetimes. In the case when the hypersurface is cut or bounded by a light-like hypersurface, the problem may not be well-defined. In order to define the volume of a hypersurface properly, we introduce the volume forms related to the given foliation (observer) of the considered spacetime. In the case of the constant curvature slice, the volume of the hypersurface cut by the horizon (light-like surface) becomes composed of the two, outer- and inner-horizon parts, treated differently. We compute the corresponding volumes outside and inside of the horizon of the eternal Schwarzschild black hole.

Anticipating forthcoming publication by the TOTEM collaboration of low-$\left|t\right|$ elastic scattering data at $\sqrt{s}$ = 13 and 2.76 TeV, hereby we emphasize the correlation between two prominent structures seen upon the otherwise exponential diffraction cone, namely a “break” staying fixed around $t\approx -$0.1 GeV² and a dip moving with energy logarithmically inwards; while at the ISR, the two structures are separated by a distance of about 1 GeV², at the LHC, the dip comes close to the periphery of the “break”, thus affecting its parametrization. An unbiased disentangling and identification of the “break” at the LHC should account for this correlation.

In this paper, we intend to extend the nuclear data of ${}^{244}\mathrm{\text{Cm}}$, ${}^{241}\mathrm{\text{Am}}$, ${}^{238}\mathrm{\text{Pu}}$, ${}^{210}\mathrm{\text{Po}}$, ${}^{147}\mathrm{\text{Pm}}$, ${}^{137}\mathrm{\text{Cs}}$, ${}^{90}\mathrm{\text{Sr}}$ and ${}^{63}\mathrm{\text{Ni}}$ nuclei used in nuclear battery technology, because, these nuclei are quite important for space investigations in radioisotope thermoelectric generator (RTG) and for microelectronic technologies in betavoltaic batteries. Therefore, the nuclear structure properties of nuclei such as separation energies, neutron skin thicknesses, proton, charge and neutron density distributions as a function of radius, the root mean square (rms) proton, charge and neutron radii, binding energies per particle, have been investigated by Hartree–Fock with eight different Skyrme forces. The obtained results have been compared with the experimental data in literature and relativistic mean field theory (RMFT) results.