arXiv subjects

Masoud Molaei

Publications and source records attributed to Masoud Molaei.

5 recordsLinked to original sources

arXiv2025

Gravitational Bound State Perturbations Inside Black Holes and Isospectrality

We study the bound state solutions for the polar perturbations in the interior of the Schwarzschild black hole. It is shown that for a given value of the spherical harmonic index $\ell$, there are a total of $\ell-1$ bound states for polar perturbations. We show both analytically and numerically that the spectrum of $\ell-2$ of these perturbations coincides exactly with the spectrum of axial perturbations. Consequently, the isospectrality between the bound states of axial and polar perturbations in the interior of the black hole is preserved. Furthermore, the additional mode found in the spectrum of polar perturbations is the algebraically special mode, which also furnishes the ground state of polar perturbations. It is shown that the spectrum of the highly excited states is equally spaced, which, in the semi-classical approximation, yields the black hole area quantization $\Delta A = 16 \pi l_{\mathrm{Pl}}^2$.

gr-qc↗

arXiv2025

Elliptically Polarized Plane Gravitational Waves

Exact plane gravitational radiation fields are presented within the framework of general relativity and their properties are described. The physics of nonlinear elliptically polarized plane gravitational waves is developed in close analogy with electromagnetic waves. The motion of free test particles in the dynamic gravitational fields of elliptically polarized plane waves is investigated. In particular, we demonstrate the cosmic jet property of these spacetimes, namely, most timelike geodesics tend to line up in the direction of wave propagation and produce a cosmic jet whose speed asymptotically approaches the speed of light.

gr-qc↗

arXiv2024

Local Peculiar Motions in McVittie and LTB Spacetimes

We consider two inhomogeneous cosmological models, namely, the flat McVittie spacetime and a simple specific LTB spacetime. Relative to the world line of a reference comoving observer that remains spatially at rest, we study the local deviations of the world lines of free test particles. These local peculiar motions can be invariantly characterized within the framework of a quasi-inertial Fermi normal coordinate system established along the world line of the reference comoving observer. Tidal dynamics in the McVittie model involves the sum of the curvature due to the inhomogeneity, the curvature due to the background FLRW spacetime and a mixed term, while tidal dynamics in the particular LTB model turns out to be qualitatively the same as in the Einstein-de Sitter universe. Peculiar motions in the two cosmological models are briefly compared and contrasted.

gr-qc↗

arXiv2024

Photon-Gravity Coupling in Schwarzschild Spacetime

A canonical formalism for quantum electrodynamics in curved spacetime is developed. This formalism enables a systematic investigation of photons in the Schwarzschild gravitational field, yielding novel results as well as refining previous results that were predicted by heuristic methods. The claim that "the gravitational redshift is a shift in the sharp frequencies of the photons for all frequencies of the spectrum" is proved. It is shown the gravitational decoherence is due to photon-gravity coupling and observer-dependent quantum electrodynamics in curved spacetime phenomena. The proper value of the photon gravitational interferometric relative phase shift is calculated and its full quantum-general relativistic nature is demonstrated. It is shown its observation will falsify the validity of Newtonian gravity and the extension of the Einstein equivalence principle beyond a single point (even in the weak uniform gravitational field.)

gr-qc↗

arXiv2023

Spin-Gravity Coupling in a Rotating Universe

The coupling of intrinsic spin with the nonlinear gravitomagnetic fields of Goedel-type spacetimes is studied. We work with Goedel-type universes in order to show that the main features of spin-gravity coupling are independent of causality problems of the Goedel universe. The connection between the spin-gravitomagnetic field coupling and Mathisson's spin-curvature force is demonstrated in the Goedel-type universe. That is, the gravitomagnetic Stern--Gerlach force due to the coupling of spin with the gravitomagnetic field reduces in the appropriate correspondence limit to the classical Mathisson spin-curvature force.

gr-qc↗