In the Ellis wormhole metrics we study characteristics of fluid dynamics and the properties of linear sound waves. By implying the energy-momentum equation and the continuity equation in the general relativistic manner we examine the flow dynamics and solve the corresponding equations for a relatively simple case - radial flow. To study the linear sound waves the equations governing the mentioned physical system are linearized and solved and interesting characteristic properties are found.
We analyze the properties of the circular orbits for massive particles in the equatorial plane of symmetric rotating Ellis wormholes. In particular, we obtain the orbital frequencies and the radial and vertical epicyclic frequencies, and consider their lowest parametric, forced and Keplerian resonances. These show that quasi-periodic oscillations in accretion disks around symmetric rotating Ellis wormholes have many distinct properties as compared to quasi-periodic oscillations in accretion disks around rotating Teo wormholes and the Kerr black hole. Still we can distinguish some common features which appear in wormhole spacetimes as opposed to black holes. The most significant ones include the possibility of excitation of stronger resonances such as lower order parametric and forced resonances and the localization of these resonances deep in the region of strong gravitational interaction near the wormhole throat, which will lead to further amplification of the signal.
The stability of one type of the static Ellis-Bronnikov-Morris-Thorne wormholes is considered. These wormholes filled with radial magnetic field and phantom dust with a negative energy density.
We consider the wormhole of Ellis, Bronnikov, Morris and Thorne (EBMT), arising from Einsteins equations in presence of a phantom scalar field. In this paper we propose a simplified derivation of the linear instability of this system, making comparisons with previous works on this subject (and generalizations) by Gonzalez, Guzman, Sarbach, Bronnikov, Fabris and Zhidenko.
Stable massless wormholes are theoretically interesting in their own right as well as for astrophysical applications, especially as galactic halo objects. Therefore, the study of gravitational lensing observables for such objects is of importance, and we do here by applying the parametric post-Newtonian method of Keeton and Petters to massless dyonic charged wormholes of the Einstein-Maxwell-Dilaton field theory and to the massless Ellis wormhole of the Einstein minimally coupled scalar field theory. The paper exemplifies how the lensing signatures of two different solutions belonging to two different theories could be qualitatively similar from the observational point of view. Quantitative differences appear depending on the parameter values. Surprisingly, there appears an unexpected divergence in the correction to differential time delay, which seems to call for a review of its original derivation.
We develop a model-independent procedure to single out static and spherically symmetric wormhole solutions based on the general relativistic Poynting-Robertson effect and the extension of the ray-tracing formalism in generic static and spherically symmetric wormhole metrics. Simulating the flux emitted by the Poynting-Robertson critical hypersurface (i.e., a stable structure where gravitational and radiation forces attain equilibrium) or also from another X-ray source in these general geometrical environments toward a distant observer, we are able to reconstruct, only locally to the emission region, the wormhole solutions which are in agreement with the high-energy astrophysical observational data. This machinery works only if wormhole evidences have been detected. Indeed, in our previous paper we showed how the Poynting-Robertson critical hypersurfaces can be located in regions of strong gravitational field and become valuable astrophysical probe to observationally search for wormholes existence. As examples, we apply our method to selected wormhole solutions in different extended theories of gravity by producing lightcurves, spectra, and images of an accretion disk. In addition, the present approach may constitute a procedure to also test the theories of gravity. Finally, we discuss the obtained results and draw the conclusions.