International Journal of Modern Physics A

This paper focuses on realistic and timely situations of inflation in connection with the CMB, gravitational and particle physics, adding interdisciplinarity and unification values within a strongly predictive physical approach. The formulation of inflation in the Ginsburg–Landau approach developed by de Vega and Sanchez¹ and by Boyanovsky, de Vega, Sanchez and Destri${}^{2-7}$ clarifies and places inflation in the setting of the effective field theories of particle physics. In addition, it sets up a clean way to directly confront the inflationary predictions with the available and forthcoming CMB data and select a definitive model. All CMB+LSS data until now show how powerful is the Ginsburg–Landau effective theory of inflation in predicting observables in agreement with observations, including the inflation energy scale and the inflaton potential, and which has much more to provide in the future. It paves the way to discoveries, new learning and understanding.

We examine an elastic medium with a disclination and consider the topological effects in the presence of a nonpolynomial quantum exactly solvable nonlinear oscillator potential related to the isotonic oscillator, and to which we refer as the Cariñena–Perelomov–Rañada–Santander (CPRS) potential. We obtain the wave functions, which are related to the confluent Heun functions, as well as the energy eigenvalues by solving exactly the corresponding radial Schrödinger equation.

In this paper an attempt has been made to study the flat fractal Friedmann–Robertson–Walker model filled with domain walls. We have obtained the fractal equation of deceleration parameter and tension of the domain wall. It is observed that, while domain walls exist at early times, they disappear at late time. Finally, some physical parameters of the model are discussed using graphs.

We review potential low-frequency gravitational-wave sources, which are expected to be detected by Taiji, a Chinese space-based gravitational-wave detector, estimate the detection rates of these gravitational-wave sources and present the parameter estimation of massive black hole binaries.

Recently, the deviation of the ratios $R(D)$, $R(D^{\ast })$ and $R(J/\psi )$ have been found between experimental data and the Standard Model predictions, which may be the hint of new physics. In this work, we calculate these ratios within the Standard Model by using the improved instantaneous Bethe–Salpeter method. The emphasis is pad to the relativistic correction of the form factors. The results are $R(D)=0.312_{-0.007}^{+0.006}$, $R(D^{\ast })=0.249_{-0.002}^{+0.001}$, $R(D_s)=0.320_{-0.009}^{+0.009}$, $R(D_s^{\ast })=0.251_{-0.003}^{+0.002}$, $R({\eta }_c)=0.384_{-0.042}^{+0.032}$, and $R(J/\psi )=0.267_{-0.011}^{+0.009}$, which are consistent with predictions of other models and the experimental data. The semileptonic decay rates and corresponding form factors at zero recoil are also given.

We propose a new scaling ansatz in the neutrino Dirac mass matrix to explain the low energy neutrino oscillations data, baryon number asymmetry and neutrinoless double beta decay. In this work, a full reconstruction of the neutrino Dirac mass matrix has been realized from the low energy neutrino oscillations data based on type-I seesaw mechanism. A concrete model based on $A_4$ flavor symmetry has been considered to generate such a neutrino Dirac mass matrix and imposes a relation between the two scaling factors. In this model, the right-handed Heavy Majorana neutrino masses are quasi-degenerate at TeV mass scales. Extensive numerical analysis studies have been carried out to constrain the parameter space of the model from the low energy neutrino oscillations data. It has been found that the parameter space of the Dirac mass matrix elements lies near or below the MeV region and the scaling factor $\left|{\kappa }_1\right|$ has to be less than 10. Furthermore, we have examined the possibility for simultaneous explanation of both neutrino oscillations data and the observed baryon number asymmetry in the Universe. Such an analysis gives further restrictions on the parameter space of the model, thereby explaining the correct neutrino data as well as the baryon number asymmetry via a resonant leptogenesis scenario. Finally, we show that the allowed space for the effective Majorana neutrino mass $m_{ee}$ is also constrained in order to account for the observed baryon asymmetry.

The study of gravitational collapse is a very interesting phenomena in general relativistic astrophysics. Here, in this study we investigated the gravitational collapse of a spherically symmetric core of a star, constituted of dark matter (DM) (${\rho }_{\mathrm{\text{DM}}}$), in dark energy (DE) (${\rho }_{\mathrm{\text{DE}}}$) background. It was investigated that gravitational collapse of interacting and noninteracting combination of DM and DE yields BH formation. In this work, our main aim is to examine the effect of space–time curvature $(k=0,1,-1)$ on the gravitational collapse of interacting and noninteracting combination of dark matter and DE. We achieve the visible influence of curvature on gravitational collapse analytically and interpret the results graphically.

We construct the lattice AdS geometry. The lattice AdS₂ geometry and AdS₃ geometry can be extended from the lattice AdS₂ induced metric, which provided the lattice Schwarzian theory at the classical limit. Then we use the lattice embedding coordinates to rewrite the lattice AdS₂ geometry and AdS₃ geometry with the manifest isometry. The lattice AdS₂ geometry can be obtained from the lattice AdS₃ geometry through the compactification without the lattice artifact. The lattice embedding coordinates can also be used in the higher-dimensional AdS geometry. Because the lattice Schwarzian theory does not suffer from the issue of the continuum limit, the lattice AdS₂ geometry can be obtained from the higher-dimensional AdS geometry through the compactification, and the lattice AdS metric does not depend on the angular coordinates, we expect that the continuum limit should exist in the lattice Einstein gravity theory from this geometric lattice AdS geometry. Finally, we apply this lattice construction to construct the holographic tensor network without the issue of a continuum limit.