arXiv subjects

Raihaneh Moti

Publications and source records attributed to Raihaneh Moti.

7 recordsLinked to original sources

arXiv2026

On the Emergence of the Hysteresis Effect in Gravitational Systems

Previously, it was shown that the interplay between the gravitational memory effect and the thermodynamics of an ensemble of spinning objects gives rise to a hysteresis effect, which can be termed Gravo-Thermo memory. This effect can be studied either through a statistical approach or via kinetic theory. Here, we present a general kinetic theory model for the general case of a fluid composed of spinning extended objects in the presence of gravity.

gr-qc↗

arXiv2025

On the Dynamics of Extended Bodies and the GravoThermo Memory Effect

The non-linearity of the theory of gravity induces a hysteresis effect in both the systems interacting with gravity and in the gravitational field. The effect is usually referred to as the memory effect. In this paper, we explore this phenomenon in the context of the dynamics of extended rotating objects in the presence of a gravitational wave pulse. Then, we consider an ensemble of such objects and show that a redistribution of spin orientations takes place as a gravitational wave passes through. We examine how this redistribution, changes the partition function and the thermodynamic quantities including entropy and energy of the system. The result shows that some information about the source of the gravitation wave is encoded in the thermodynamics of the system.

gr-qc↗

arXiv2024

On the Gravitational Hysteresis in the Kinetic Theory

General theory of relativity is non--linear in nature and therefore can result in hysteresis-like effects and cause systems to remember the footprint of the gravitational field. Here we have investigated this effect using the Kinetic theory in curved spacetime. It is shown that the entropy rate experiences this hysteresis behavior. The effect is then considered for some special spacetimes, including Schwarzschild black hole, Friedmann--Lemaître--Robertson--Walker cosmological solution, and the flat Minkowski spacetime perturbed by a gravitational wave pulse. It is shown that there is some hysteresis effect for the entropy rate.

gr-qc↗

arXiv2023

On the Gravitational Precession Memory Effect for an Ensemble of Gyroscopes

We study the thermodynamic properties of a freely falling ensemble of gyroscopes after the passage of a weak gravitational wave. Due to the precession memory effect, the thermodynamic quantities will experience a change because of the space-time perturbation. We discuss that this GravoThermo memory effect potentially can be used for the detection of the gravitational waves.

gr-qc↗

arXiv2023

On the Nonlocal Newtonian Cosmology

In the absence of an exact development of the cosmological models based on the Mashhoon nonlocal gravity, the Newtonian regime clarifies some aspects of it. To improve this model more reliable, going through some semi-Post-Newtonian considerations may be useful. One important feature to consider is the formation of horizons, which can be understood as a consequence of the finite interaction velocity. This highlights the importance of extending the integration across the entire space-time, rather than solely focusing on the spatial sector. In this context, we show that the density of effective dark matter would increase, while the density of Baryonic matter decreases, during the deep matter-dominated era. This finding is in contradiction with the predictions of the standard model of cosmology and it raises concerns about the compatibility of using Tohline--Kuhn kernel and considering the nonlocal effects as an effective dark matter in $Λ$CDM.

gr-qc↗

arXiv2022

On the quantum gravastar

In this paper, we show that it is possible to have pure quantum gravastar solution to the quantum improved Einstein equations. Such an object is essentially a gravastar in which the thin layer of matter is replaced by quantum effects. The metric of a pure quantum gravastar is obtained and its stability is discussed.

gr-qc↗

arXiv2021

On the Quantum Improved Affine Gravity

Improvement of the classical gravity with the running gravitational coupling obtained from asymptotically safe gravity, is a good way of considering the effects of quantum gravity. This is usually done for metric theories of gravity. Here we investigate the effects of such an improvement for pure affine theories of gravity. To motivate the approach, we first consider the effects of quantum improvement on the connection using metric theory and investigate the effects on the causal structure of black hole solution. Next in the framework of Schrödinger-Eddington affine theory, the general way of affine improvement is presented and a spherically symmetric solution is obtained and compared with other ways of improvement.

gr-qc↗