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Universe, Volume 10, Issue 1

January 2024 - 52 articles

Cover Story: In this article, we study the form of the deviation of geodesics (tidal forces) and the Raychaudhuri equation in a Schwarzschild–Finsler–Randers (SFR) spacetime which has been investigated in previous papers. This model is obtained by considering the structure of a Lorentz tangent bundle of spacetime and, in particular, the kind of the curvatures in generalized metric spaces where there is more than one curvature tensor, such as Finsler-like spacetimes. In these cases, the concept of the Raychaudhuri equation is extended with extra terms and degrees of freedom from the dependence on internal variables such as the velocity or an anisotropic vector field. Additionally, we investigate some consequences of the weak-field limit on the spacetime under consideration and study the Newtonian limit equations which include a generalization of the Poisson equation. View this paper
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Articles (52)

  • Article
  • Open Access
2 Citations
1,865 Views
15 Pages

A Partial Eruption of a Sigmoid Filament in the Small Dipole Active Region 12734

  • Jihong Liu,
  • Yin Zhang,
  • Yuhong Zheng,
  • Yu Liu and
  • Jie Chen

16 January 2024

We present a detailed analysis of a partial eruption of a sigmoid filament lying along the polarity inversion line (PIL) of the small active region (AR) NOAA 12734 (with an area of 1.44 ×103 square megameters). The active filament was rooted in...

  • Communication
  • Open Access
5 Citations
1,906 Views
12 Pages

16 January 2024

We imagine spherically symmetric configurations made of both dark matter and dark energy in the halo of spiral galaxies. Adopting a polytropic equation of state for dark matter and the Extended Chaplygin gas equation of state for dark energy, we mode...

  • Article
  • Open Access
1 Citations
2,293 Views
12 Pages

16 January 2024

Using data from the MESSENGER spacecraft magnetometer that describes the magnetopause and the bow shock crossing points of the Mercury’s magnetosphere, we have calculated the parameters of the paraboloids of revolution approximating the obtaine...

  • Article
  • Open Access
9 Citations
2,074 Views
16 Pages

14 January 2024

We study the second-order scalar and density perturbations generated by Gaussian curvature perturbations and primordial gravitational waves in the radiation-dominated era. After presenting all the possible second-order source terms, we obtain the exp...

  • Article
  • Open Access
1,691 Views
15 Pages

12 January 2024

The chromomagnetic vacuum of SU(2) gluodynamics is considered in the background of a finite radius flux tube (center vortex) with a homogeneous field inside and a zero field outside. In this background, there are tachyonic modes. These modes cause an...

  • Article
  • Open Access
1 Citations
2,024 Views
17 Pages

12 January 2024

We examine the flux density ratio anomaly in the quadruply imaged strong gravitational lens, B1422+231, and consider the contribution of 10–103M⊙ primordial black holes (PBHs) as a potential dark matter constituent. We describe the first...

  • Article
  • Open Access
3 Citations
2,023 Views
17 Pages

12 January 2024

Within the framework of the quantum-statistical approach, utilizing both non-Hermitian Hamiltonian and Lindblad’s jump operators, one can derive various generalizations of the von Neumann equation for reduced density operators, also known as hy...

  • Article
  • Open Access
2 Citations
1,546 Views
11 Pages

12 January 2024

In this study, we developed a new method for finding the quantum probability density of arrival at the detector. The evolution of the quantum state restricted to the region outside of the detector is described by a restricted Hamiltonian that contain...

  • Article
  • Open Access
1 Citations
2,226 Views
14 Pages

Measures of Distance in Quantum Mechanics

  • Pawel Gusin,
  • Daniel Burys and
  • Andrzej Radosz

12 January 2024

Combining gravity with quantum theory is still a work in progress. On the one hand, classical gravity is the geometry of space-time determined by the energy–momentum tensor of matter and the resulting nonlinear equations; on the other hand, the...

  • Article
  • Open Access
2 Citations
2,112 Views
24 Pages

11 January 2024

We study the evolution of quantum fluctuations of gravity around an inflationary solution in renormalizable quantum gravity, in which the initial scalar-fluctuation dominance is shown by the background-free nature expressed by a special conformal inv...

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Universe - ISSN 2218-1997