Modern Physics Letters A

An equality of particle and antiparticle gravitational interactions holds in general relativity and is supported by indirect observations. Gravity dependence on rotation or spin direction is experimentally constrained for non-relativistic matter. Here, a method based on high-energy Compton scattering is developed to measure the gravitational interaction of accelerated charged particles. Within that formalism, the Compton spectra measured at HERA rule out the speculated anti-gravity possibility for antimatter at a confidence level close to 100%. The same data, however, imply a gravitational CP violation around 13 GeV energies, by a maximal amount of $(9\pm 2)\cdot 10^{-12}$ for the charge and $(13\pm 3)\cdot 10^{-12}$ for the space parity. The detected asymmetry hints for a stronger gravitational coupling to left helicity electrons relative to right helicity positrons.

The renormalized quantum stress–energy tensor ${〈T_{\mu }^{\nu }〉}_{\mathrm{\text{ren}}}$ for a massive spinor field around global monopoles is constructed within the framework of Schwinger–DeWitt approximation, valid whenever the Compton length of the quantum field is much less than the characteristic radius of the curvature of the background geometry. The results obtained show that the quantum massive spinor field in the global monopole spacetime violates all the pointwise energy conditions.

To describe interactions in the universe in a more realistic way, we used the generic model of Klein–Gordon equation with four inverse power term potentials. Using bi-confluent Heun function, we obtained a transcendental energy equation and the wave function. Moreover, we determined the non-relativistic energy. Special cases of the potential have also been discussed. These results obtained are highly applicable in many branches of physics and life sciences.

The trilinear terms of the form $\sqrt{2}f{𝜖}^{ijk}{\rho }_i{\chi }_j{\varphi }_k$ in the scalar potential of a 3-3-1 gauge model are considered. When looking for the eigenbasis of the massive physical Higgs bosons that survive the spontaneous symmetry breakdown of the model — in light of the observed SM-like Higgs boson with mass $m_h\simeq 125$ GeV reported in 2012 at the LHC — one gets a strong constraint to the cubic term. It has to be $f\ll w$, in flagrant contradiction with the large one $f\simeq w$ which is propagated in the literature to date.

The expressions for the corrected radius and the Hawking temperature of a Schwarzschild black hole are derived by calculating the total energy of a self-gravitating system of N fermions when the corrections to gravitational interaction due to post-Newtonian-like self-energy due to two graviton exchange- and one-loop contribution of quantum gravity effect are included. Since the particles are fermions, the exchange-correlation energy is also included consistently. It is found that though the three corrections are small, the correction due to the exchange-correlation is much more than the other two. The configuration of the many-particle system that we study is possible since it has no Buchdahl limit in the post-Newtonian approximation.

The constraints on a general form of the power-law potential and the dissipation coefficient in the framework of warm single field inflation imposed by Planck data will be investigated. By considering a quasi-static Universe, besides a slow-roll condition, the suitable regions in which a pair of theoretical free parameters are in good agreement with Planck results will be estimated. In this method, instead of a set of free parameters, we can visualize a region of free parameters that can satisfy the precision limits on theoretical results. On the other side, when we consider the preformed quantity for the amplitude of scalar perturbations, the conflict between obtained results for free parameters in different steps will be dramatically decreased. As done in prominent literature, based on the friction of the environment, we can divide the primordial Universe into two different epochs, namely weak and strong dissipative regimes. For the aforementioned eras, the free parameters of the model will be constrained and the best regions will be obtained. To do so, the main inflationary observables such as tensor-to-scalar ratio, power-spectra of density perturbations and gravitational waves, scalar and tensor spectral indices, running spectral index and the number of e-folds in both weak and strong regimes will be obtained. Ultimately, it can be visualized, this model can make concord between theoretical results and data originated from cosmic microwave background and Planck 2013, 2015 and 2018.

We are investigating if the double copy structure as product of scattering amplitudes of gauge theories applies to cosmological correlators computed, in a class of theories for inflation, by the operatorial version of the In–In formalism of Schwinger–Keldysh. We consider tree-level momentum–space correlators involving primordial gravitational waves with different polarizations and the scalar curvature fluctuations on a three-dimensional fixed spatial slice. The correlators are sum of terms factorized in a time-dependent scalar factor, which takes into account the curved background where energy is not conserved, and in a so-called tensor factor, constructed by polarization tensors. In the latter, we recognize scattering amplitudes in four-dimensional Minkowski space spanned by three points gravitational amplitudes related by double copy to those of gauge theories. Our study indicates that gravitational waves are double copy of gluons and the primordial scalar curvature is double copy of a scalar with Higgs-like interactions.

The mass of a system in general relativity cannot be defined locally. Thus, one defines mass at quasilocal level. There are many definitions of quasilocal mass. One of them is the Hawking mass. In this paper, we determine the Hawking mass for ellipsoidal 2-surface for a non-Schwarzschild spacetime. In order to do this, we first determine a null tetrad and then compute the Hawking mass. The results are presented graphically also.

We have developed a formalism in the non-relativistic scenario to obtain the time evolution of the eigenstates of Rindler Hamiltonian in momentum space. Hence, the particle wave function in spacetime coordinates is obtained using Fourier transform of the momentum space wave function. We have discussed the difficulties with characteristic curves, and re-cast the time evolution equations in the form of two-dimensional Laplace equation. The solutions are obtained both in polar coordinates as well as in the Cartesian form. It has been observed that in the Cartesian coordinate, the probability density is zero both at $t=0$ (the initial time) and at $t=\infty$ (the final time) for a given $x$-coordinate. The reason behind such peculiar behavior of the eigenstate is because it satisfies (1 + 1)-dimensional Laplace equation. This is of course the mathematical explanation, whereas physically we may interpret that it is because of the Unruh effect.

In this paper, we use the q-derivative emerging in the non-extensive statistical physics to formulate the q-deformed quantum mechanics. We find the algebraic structure related to this deformed theory and investigate some properties of the q-deformed elementary functions. Using this mathematical background, we formulate the q-deformed Heisenberg algebra and q-deformed time-dependent Schrödinger equation. As an example, we deal with the infinite potential well and compute the Fermi energy in the q-deformed theory.

This work deals with the decay analysis of three compound nuclei ${}^{77}{\mathrm{\text{As}}}^{\ast }$, ${}^{83}{\mathrm{\text{Br}}}^{\ast }$ and ${}^{86}{\mathrm{\text{Sr}}}^{\ast }$ formed in proton-induced reactions $\mathrm{\text{p}}+{}^{76}\mathrm{\text{Ge}}$, $\mathrm{\text{p}}+{}^{82}\mathrm{\text{Se}}$ and $\mathrm{\text{p}}+{}^{85}\mathrm{\text{Rb}}$ at incident beam energies of 1–5 MeV using the Dynamical Cluster-decay Model (DCM). The motive is to explore the decay of compound systems formed via light charged particles as projectiles. The experimentally available data of n-evaporation for the aforementioned systems are addressed by optimizing the neck-length parameter $\mathrm{\Delta }R$, using spherical fragmentation approach. The comparative analysis of the decay structure of the chosen systems is carried out at a common incident beam energy $E_{\mathrm{\text{beam}}}\sim 3.6$ MeV. The effect of angular momentum $(\ell )$ and quadrupole $({\beta }_2)$-deformations is explored in reference to the decay structure/fragmentation of compound systems. In addition to this, the sensitivity of DCM-based cross-sections toward level density parameter (LDP) $a$ is also analyzed. The relative role of mass-dependent level density parameter $a(A)$ is also investigated for compound systems belonging to light and heavy mass region. Lastly, a theoretical systematics is explored where the proton beam in the reaction $\mathrm{\text{p}}+{}^{76}\mathrm{\text{Ge}}$ is replaced by a neutron beam forming the compound system ${}^{77}{\mathrm{\text{Ge}}}^{\ast }$, having the same $A$, but $Z$ one less than that of the compound system formed in the reaction using proton beam, and its effect on the decay characteristics such as preformation probability, penetration probability and barrier height is analyzed.