Wormhole Research Articles

Deflection angle for charged wormhole in f(R,T) gravity

This paper is focused on the study of charged wormholes which are combinations of Morris–Thorne wormhole and Reissner–Nordström spacetime. Gravitational lensing is an important tool which has been adopted to detect various objects like wormholes using the notion of deflection angle. In this work, we have evaluated deflection angle with and without using the strong field limit coefficients and compared the results. Further, exact charged wormhole solutions are obtained in [Formula: see text] gravity and the nature of the energy conditions is examined.

Morris-Thorne wormhole in the vector-tensor theories with Abelian gauge symmetry breaking

We construct an asymptotically flat Morris-Thorne wormhole solution supported by anisotropic matter fluid and a vector field which is coupled to gravity in a nonminimal way with broken Abelian gauge symmetry. In this paper, a specific shape function is considered. We find that the ansatz of vector field plays a significant role in determining the spacetime geometry of the wormhole. If there exists the electrostatic potential only, the redshift function could be considered as a constant value, implying the vanishing tidal force. However, when the vector potential in radial-direction is involved, the r-component of extended Maxwell equations at the wormhole's throat is invalid. To solve this issue, a thin shell is introduced near the throat, dividing the spacetime into two parts. Furthermore, it is proved that the spacetime geometry of wormhole could be smooth at junction position if the expressions of redshift function and vector potential are given appropriately. Finally, the energy conditions and the volume integral quantifier are explored.

Morris–Thorne wormholes in modified f(R, T) gravity

Wormhole solutions obtained by Morris and Thorne (MT) in general relativity (GR) is investigated in a modified theory of gravity. In the gravitational action, we consider f(R, T) which is a function of the Ricci scalar (R) and the trace of the energy-momentum tensor (T). In the framework of a modified gravity described by $$f(R,T)=R+\alpha R^{2}+\lambda T^{\beta }$$ , where $$\alpha $$ , $$\beta $$ and $$\lambda $$ are coupling constants, MT wormhole (WH) solutions with normal matter are obtained for a relevant shape function. We have considered two different values of $$\beta $$ leading to two forms of f(R, T)-gravity. The energy conditions are probed at the throat and away from the throat of the WH. It is found that the coupling parameters, $$\alpha $$ and $$\lambda $$ in the gravitational action play an important role in deciding the matter composition in the wormholes. It is found that for a given $$\lambda $$ , WH exists in the presence of exotic matter at the throat when $$\alpha <0$$ . It is demonstrated here that WH exists even without exotic matter for $$\alpha >0$$ in the modified gravity. Two different shape functions are considered to obtain WH solutions that are permitted with or without exotic matter. It is noted that in a modified f(R, T) gravity MT WH is permitted with normal matter which is not possible in GR. It is demonstrated that a class of WH solutions exist with anisotropic fluid for $$\lambda \ne -8\pi $$ . However, for flat asymptotic regions with anisotropic fluids WH solutions cannot be realized when $$\lambda =-8\pi $$ . All the energy conditions are found consistent with the hybrid shape function indicating existence of WH even with normal matter for $$\lambda \rightarrow 0$$ .

Computing the temporal intervals by making a Throne-Morris wormhole from a Kerr black hole in the context of f(R,T) gravity

In the paper we will proceed towards taking the larger root of and make it equal to zero to remove the event horizon of a Kerr black hole (BH) in Boyer-Lindquist coordinates with a prevalent ring type singularity that can be smoothen by a tunneling approach of a spherinder thereby proceeding safely towards the Cauchy horizon with the deduced intervals computed in detail for the time travel in the Throne-Morris wormhole (WH) approach under gravity without the presence of any exotic matter at the WH mouth thereby preserving the asymptotically solutions of flaring out conditions and mouth opening during the course of the journey through the Einstein-Rosen bridge. An approach has been organized in the paper in which not only time travel is possible without exotic matter but also time travel is flexible to past and future in the Einstein’s universe by eliminating all sorts of paradoxes by spatial sheath through 2D approach of temporal dimensions.

Thermodynamics of traversable wormholes in f(R,T) gravity

In this paper, we discuss thermodynamics for spherically symmetric and static traversable wormholes which include Morris–Thorne wormholes and charged wormholes in the background of [Formula: see text] gravity. The local coordinates have been used to find trapping horizons of these objects and generalized surface gravity has been worked out on the trapping horizons. The expression for the unified first law has also been derived from the gradient of Misner–Sharp energy with the help of gravitational field equations and from this law the first law of wormhole dynamics has been obtained. We have done this analysis for the simplest case of [Formula: see text] gravity where [Formula: see text], [Formula: see text] and [Formula: see text] being the traces of the Ricci and stress–energy tensors. Also, we have extended these thermodynamic results to non-minimal curvature-matter coupling.

Casimir effect nearby and through a cosmological wormhole

In this letter, we investigate the changes in the quantum vacuum energy of the massless scalar field inside a Casimir cavity that orbits a wormhole. We consider a cosmological model with the isotropic form of the Morris-Thorne wormhole, embedded in the FLRW Universe. In this sense, we examine the effects of global curvature and scale factor in an instant of the cosmic history, besides the influences of the local geometry and inertial forces, on the Casimir energy density. We also study the behavior of this quantity when each plate is positioned without rotation at opposite sides of the wormhole throat, at zero and finite temperatures, taking into account the effective distance between the plates through the wormhole throat.

Mitigate Wormhole Attack and Blackhole Attack Using Elliptic Curve Cryptography in MANET.

Numerous network can be connected by using the mobile ad hoc network. It can have security attacks like the worm hole, denial of service attack, jellyfish and also the blackhole. During this they take a path which is the shortest for the place where it has to reach. During sending of message two types of attacks are generally seen such as the blackhole attack and the wormhole attack. In this research we have tried to focus on two major attacks such as the black hole and the worm hole attack. In this we have used two types of protocol such as the AODV whose other name is SWBAODV and the scalable-dynamic elliptic curve cryptography. During the use the prime numbers are selected at random. We can also choose certain specific prime number. Moreover the security level does not depend on the size of the key. Keeping A as worm hole and B as the black hole we have made a two dimensional vector function named as F [A, B]. Two types of study is done by us in our research such as the with attack and without attack. In case of no attack study we have shown graphically using the AODV and the in case of attack we have given it as the BAODV and also the WAODV. Here we have applied a specific method SWBAODV to our selected attack case. The results were found to be interesting for the case of, packet delivery ratio and end to end delay was near 188.40 on comparing it with the BAODV and the WAODV. It has shown 51.38% more value compared to the BAODV and WAODV. There has been a drastic fall in the value of delay and it reached to a 63.2 for BAODV to WAODV. The other two things which we have discussed here is the consumption of energy and the overhead routing. The results in case of SWBAODV were good compared with the consumption of energy and save about 73.52% with the attacked case and around 69.35% with the routing done on the BAODV and WAODV. From our study we were able to say that it will give protection to the (MANET).

Thermodynamics of dynamical wormholes

We study thermodynamics of dynamical traversable wormholes. The surface gravity is evaluated on the trapping horizon and the unified first law of thermodynamics is set up. The thermodynamic stability of these wormholes has been investigated. We have also extended these results to charged dynamical wormholes. Our results generalize those that exist for static Morris-Thorne wormholes.

A new shape function for wormholes in [formula omitted] gravity and general relativity

In the present work, a new shape function is proposed inside modified f(R) gravity and General Relativity in wormhole (WH) geometry. The shape function obeyed all the desired conditions of WH geometry. The equation of state (EoS) parameter, anisotropy parameter and the energy conditions are computed. The tangential null energy conditions and the weak energy condition are validated, as well as the radial energy conditions, which demonstrates the nonappearance of exotic matter due to modified gravity allied with such a new proposal.

Gravitational perturbations in the Newman-Penrose formalism: Applications to wormholes

In this work we study the problem of linear stability of gravitational perturbations in stationary and spherically symmetric wormholes. For this purpose, we employ the Newman-Penrose formalism which is well-suited for treating gravitational radiation in General Relativity, as well as the geometrical aspect of this theory. With this method we obtain a "master equation" that describes the behavior of gravitational perturbations that are of odd-parity in the Regge-Wheeler gauge. This equation is later applied to a specific class of Morris-Thorne wormholes and also to the metric of an asymptotically flat scalar field wormhole. The analysis of the equations that these space-times yield reveals that there are no unstable vibrational modes generated by the type of perturbations here studied.

Effect of Treatment Conditions on Matrix Stimulation of Carbonate Rocks with Chelating Agents

This study aimed to optimize the acidizing efficiency during stimulation treatments with chelating agents. The performance of hydroxylethylethylenediaminetriacetic acid (HEDTA), diethylenetriaminepentaacetic acid (DTPA), and ethylenediaminetetraacetic acid (EDTA) in stimulating carbonate rocks were investigated. In this paper, the effect of injection rate, chemical type, pH, and concentration on the stimulation performance was studied. Also, the optimum treatment conditions were identified utilizing the acid volume and treatment time. Different measurements were carried out, including solubility tests, coreflooding experiments, and CT scan analysis. Solubility tests were performed to study the impact of solution concentration and pH on the performance of the chelating agent. Coreflooding experiments were carried out at high-pressure, high-temperature conditions to assess the performance of chelating agents in different treatment situations. In addition, CT scan analysis was carried out before and after the acid injections to capture the changes induced in the carbonate matrix due to the stimulation treatment. The success of acidizing treatment was identified by the creation of the dominant wormholes. The pressure-drop profiles and the CT scan analysis were used to confirm the generation of wormholes. Finally, the normalized volume and time to breakthrough were utilized to identify the optimum treatment conditions. In this work, chelating agents successfully created dominant wormholes (WHs) in carbonate rocks at different injection rates and treatment conditions. However, applying an injection rate between 0.7 and 1 cm3/min significantly improved the acidizing performance and reduced the acid volume that was required to create wormholes. EDTA and HEDTA chelating agents showed better performance at low pH. Using a solution pH of 4.5 resulted in reducing the acid volume by 30% compared to using a solution pH of 10 at the same conditions. However, DTPA chelating agent showed better performance at high pH, and dominant WHs were created at a pH of 12 using less acid volume. Finally, the optimum acidizing treatment can be achieved by using EDTA chelating agent with a concentration of 9.25 wt.% and pH of 4.5. Applying the optimum treatment parameters can reduce the acid volume by 40% and the chemical cost by a factor of 6, on average. Overall, this study indicates that chelating agents’ solution can be injected at optimum conditions in terms of chemical concentration, pH, and injection rate, to maximize the treatment efficiency and reduce the cost.

Accretions of Tsallis, Rényi and Sharma–Mittal dark energies onto higher-dimensional Schwarzschild black hole and Morris–Thorne wormhole

In this work, we study the dark energy accretion phenomena onto [Formula: see text]-dimensional Schwarzschild black hole and [Formula: see text]-dimensional Morris–Thorne wormhole. We obtain the [Formula: see text]-dimensional Schwarzschild black hole mass and [Formula: see text]-dimensional Morris–Thorne wormhole mass and their rate of change of masses due to accretion. For the dark energy component, we consider Tsallis, modified Rényi and “modified” Sharma–Mittal holographic dark energy (HDE) and new agegraphic dark energy (NADE). We also find the black hole mass and the wormhole mass in terms of redshift when cold dark matter and the specified forms of dark energies accrete onto them. In most cases, the black hole mass increases, and wormhole mass decreases for HDE and NADE accretions. The only exception is the Sharma–Mittal NADE, where the black hole mass decreases and wormhole mass increases during the evolution of the Universe. However, the slope of increasing/decreasing mass significantly depends on the dimension in almost all cases.

Worm holes in immunity.

Intestinal helminths can increase the lethality of a subsequent coinfection with neurotropic flaviviruses by activating tuft cells and type 2 immune mechanisms in the gut.

Noncommutative-Geometry Wormholes with Isotropic Pressure

The strategy adopted in the original Morris-Thorne wormhole was to retain complete control over the geometry at the expense of certain engineering considerations. The purpose of this paper is to obtain several complete wormhole solutions by assuming a noncommutative-geometry background with a concomitant isotropic pressure condition. This condition allows us to consider a cosmological setting with a perfect-fluid equation of state. An extended form of the equation generalizes the first solution and subsequently leads to the generalized Chaplygin gas model and hence to a third solution. The solutions obtained extend several previous results. This paper also reiterates the need for a noncommutative-geometry background to account for the enormous radial tension that is a characteristic of Morris-Thorne wormholes.

Charged Wormholes in Spacetimes of Embedding Class One

The existence of charged black holes has suggested that wormholes may also be charged. The purpose of this paper is to construct a general model of a charged wormhole that proves to be a natural extension of the original Morris-Thorne wormhole. This goal is achieved by means of the classical embedding theory that has played a major role in the general theory of relativity.

Diving into a holographic superconductor

Charged black holes in anti-de Sitter space become unstable to forming charged scalar hair at low temperatures T &lt; T_\text{c}T&lt;Tc. This phenomenon is a holographic realization of superconductivity. We look inside the horizon of these holographic superconductors and find intricate dynamical behavior. The spacetime ends at a spacelike Kasner singularity, and there is no Cauchy horizon. Before reaching the singularity, there are several intermediate regimes which we study both analytically and numerically. These include strong Josephson oscillations in the condensate and possible `Kasner inversions’ in which after many e-folds of expansion, the Einstein-Rosen bridge contracts towards the singularity. Due to the Josephson oscillations, the number of Kasner inversions depends very sensitively on TT, and diverges at a discrete set of temperatures \{T_n\}{Tn} that accumulate at T_cTc. Near these T_nTn, the final Kasner exponent exhibits fractal-like behavior.

A deep learning- based frechet and dirichlet model for intrusion detection in IWSN

Industrial Wireless Sensor Network (IWSN) includes numerous sensor nodes that collect data about target objects and transmit to sink nodes (SN). During data transmission among nodes, intrusion detection is carried to improve data security and privacy. Intrusion detection system (IDS) examines the network for intrusions based on user activities. Several works have been done in the field of intrusion detection and different measures are carried out to increase data security from the issues related to black hole, Sybil attack, Worm hole, identity replication attack and etc. In various existing approaches, secure data transmission is not achieved, therefore resulted in compromising the security and privacy of IWSNs. Accurate intrusion detection is still challenging task in terms of improving security and intrusion detection rate. In order to improve intrusion detection rate (IDR) with minimum time, generalized Frechet Hyperbolic Deep and Dirichlet Secured (FHD-DS) data communication model is introduced. At first, Frechet Hyperbolic Deep Traffic (FHDT) feature extraction method is designed to extract more relevant network activities and inherent traffic features. With the help of extracted features, anomalous or normal data is predicted. Followed by Statistical Dirichlet Anomaly-based Intrusion Detection model is applied to discover intrusion. Here, Dirichlet distribution is evaluated to attain secure data transmission and significantly detect intrusions in WSNs. Experimental evaluation is carried out with KDD cup 99 dataset on factors such as IDR, intrusion detection time (IDT) and data delivery rate (DDR). The observed results show that the generalized FHD-DS data communication method achieves higher IDR with minimum time.

Yates Algorithm to Analyze the Performance of MANET Routing Protocol

To test the performance of any routing protocol in Mobile Ad hoc Network (MANET), the re-searchers simulate their scenarios several times with different simulators to get either positive or negative results. This operation of the simulation can last many hours and sometimes several days depending on the performance either of the software or the hardware, and the number of factors used to analyze. In this paper, we propose a new method reckons on the Yates algorithm that are considered as a solution to evaluate the performance of any MANET routing protocols under the effect of any number of factors. This approach allows creating a simulation model in the form of mathematical formulas. To check the efficiency of our proposed method we chose Optimized Link State Routing Protocol (OLSR) as MANET routing protocol and the effect of four factors which are: The Black Hole attack, Worm Hole attack, Node Speed and the Pause Time.

On the Nature of Exotic Matter in Morris-Thorne Wormholes

It is well known that phantom energy, which is characterized by the equation of state p = ωρ, ω &lt; −1, can support Morris-Thorne wormholes since it leads to a violation of the null energy condition. The purpose of this note is to show that the converse is also true in the following sense: for a typical shape function, the equation of state of exotic matter in the vicinity of the throat is given by p↓r = ωρ, ω &lt; −1, where pr is the radial pressure.

Dynamics in wormhole spacetimes: a Jacobi metric approach

This article deals with the study of the dynamics of particles in different wormhole geometries. Using the Jacobi metric approach we study the geodesic motion on the Morris–Thorne wormhole. We found the only stable circular orbit located at the throat. We show that the Gaussian curvature of the Jacobi metric is directly related with the wormhole flare-out condition. We provide a simple test for determining the existence of a throat in a spacetime by using the Gaussian curvature of the associated Jacobi metric only. We discuss about the trajectories in the Kepler problem in a wormhole background. Finally, we discuss about the restrictions over the stress–energy tensor imposed by the existence of elliptic orbits in the Kepler problem.