Thin-shell Wormholes Research Articles

Photon surfaces as pure tension shells: Uniqueness of thin shell wormholes

Thin shell wormholes are constructed by joining two asymptotically flat spacetimes along their inner boundaries. The junction conditions imposed on the spacetimes specify the equation of state of the matter called thin shell distributed along the joined boundaries. Barcelo and Visser (2000) reported that spherically symmetric thin shell wormholes have their shells, namely the wormhole throats, on the photon spheres if the wormholes are $Z_2$-symmetric across the throats and the shells are of pure tension. In this paper, first, we consider general joined spacetimes (JSTs) and show that any $Z_2$-symmetric pure-tensional JST (Z2PTJST) of $\Lambda$-vacuum has its shell on a photon surface, a generalized object of photon spheres, without assuming any other symmetries. The class of Z2PTJSTs also includes, for example, brane world models with the shells being the branes we live in. Second, we investigate the shell stability of Z2PTJSTs by analyzing the stability of the corresponding photon surfaces. Finally, applying the uniqueness theorem of photon spheres by Cederbaum (2015), we establish the uniqueness theorem of static wormholes of Z2PTJST.

Thin-shell wormholes in f(R)-gravity coupled with nonlinear electrodynamics

We study the possibility of constructing thin-shell wormhole (TSW) in a particular $$f\left( R\right) $$ -gravity model with nonconstant Ricci scalar and coupled minimally with nonlinear electromagnetic fields. In doing so, first we give a new static spherically symmetric solution of the theory. Then we apply the cut-and-paste method to construct the TSW. As $$f^{\prime \prime \prime }\left( R\right) \ne 0$$ we use the specific junction conditions to match the two spacetimes. We find the exact equilibrium radius of the shell from non-black hole solution and show that a linear perturbation leaves the TSW stable.

Thin-shell wormhole satisfying energy conditions

The quartic self-interacting conformal scalar field is used to construct a thin-shell wormhole satisfying all energy conditions. Accompanying the scalar field in the theory is the extremal Reissner-Nordström black hole with a positive cosmological constant. New junction conditions apt for the higher-order terms are derived in the Gaussian normal coordinates.

Dynamics of thin-shell wormholes with rotational effects

This paper is devoted to the study of the stability of thin-shell wormholes from Kerr black hole. We employ Israel thin-shell formalism to evaluate surface stresses and study the behavior of energy conditions. The linearized stability of rotating thin-shell wormholes is analyzed by taking two different candidates of dark energy as exotic matter at thin-shell. It is found that generalized phantom model ([Formula: see text] which reduces to phantom equation of state as [Formula: see text] and [Formula: see text], where [Formula: see text] is wormhole throat radius and [Formula: see text] is the proper time) yields more stable wormhole solutions as compared to the barotropic equation of state ([Formula: see text], [Formula: see text] is the equation of state parameter and [Formula: see text] is the surface density) for particular ranges of equilibrium throat radius and the whole range of [Formula: see text].

Stability of charged Kiselev thin-shell wormholes

This work is devoted to exploring the stability of thin-shell wormholes developed from two equivalent copies of charged quintessence (charged Kiselev) black holes by using Visser cut and paste approach. The characteristics of the surface matter of the shell are determined by using Israel formalism. We examine the stability of thin-shell by assuming a barotropic equation of state for the surface matter of the wormhole throat. We conclude that wormhole becomes stable in the presence of both charge and Kiselev parameter otherwise, it shows an unstable behavior.

Curvature Invariants for Lorentzian Traversable Wormholes

The curvature invariants of three Lorentzian wormholes are calculated and plotted in this paper. The plots may be inspected for discontinuities to analyze the traversability of a wormhole. This approach was formulated by Henry, Overduin, and Wilcomb for black holes (Henry et al., 2016). Curvature invariants are independent of coordinate basis, so the process is free of coordinate mapping distortions and the same regardless of your chosen coordinates (Christoffel, E.B., 1869; Stephani, et al., 2003). The four independent Carminati and McLenaghan (CM) invariants are calculated and the nonzero curvature invariant functions are plotted (Carminati et al., 1991; Santosuosso et al., 1998). Three traversable wormhole line elements analyzed include the (i) spherically symmetric Morris and Thorne, (ii) thin-shell Schwarzschild wormholes, and (iii) the exponential metric (Visser, M., 1995; Boonserm et al., 2018).

Stability of charged rotating (2 + 1)-dimensional wormholes

This paper investigates the effects of charge on linearized stability of rotating thin-shell wormholes (WHs) filled with a barotropic fluid. We use Visser cut and paste technique to construct thin-shell from charged rotating Bañados–Teitelboim–Zanelli (BTZ) black holes (BHs). The components of stress-energy tensor are evaluated through Israel thin-shell formalism. The angular momentum for both interior as well as exterior region at the WH throat remains the same but opposite in direction, i.e. thin-shell WH at the throat is counter-rotated. It is found that the geometrical structure of WHs is more stable for highly charged and fast rotating thin-shell. We conclude that the stability regions of charged rotating WHs are larger than the uncharged rotating WHs.

3+1-Dimensional GR versus dRGT massive gravity: a thin-shell wormholes comparison

Spherically static black hole solution in vacuum GR and dRGT massive gravity with identical radius of event horizons are compared. First, we analyze the differences between the two theories in terms of some basic thermodynamics properties such as the Hawking temperature and the specific heat capacity. Then, for a more detailed comparison we construct thin-shell wormholes in both theories and study their different aspects, namely the amount of the exotic matter and the linear dynamic stability.

Seeking connections between wormholes, gravastars, and black holes via noncommutative geometry

Noncommutative geometry, an offshoot of string theory, replaces point-like objects by smeared objects. The resulting uncertainty may cause a black hole to be observationally indistinguishable from a traversable wormhole, while the latter, in turn, may become observationally indistinguishable from a gravastar. The same noncommutative-geometry background allows the theoretical construction of thin-shell wormholes from gravastars and may even serve as a model for dark energy.

Linearized stability of Bardeen-de Sitter thin-shell wormholes

A thin-shell wormhole is crafted by the cut-and-paste method of two Bardeen-de Sitter black holes using the Darmois-Israel formalism. Energy conditions are considered for different values of magnetic charge while both mass and cosmological constant are fixed. The attractive and repulsive characteristics of the throat of the thin-shell wormhole are also examined through the radial acceleration. Dynamics and stability of the wormhole are studied around the static solutions of the linearized radial perturbations at the throat of the wormhole. The regions of stability are determined by checking out the condition of concavity of the potential as a function in the throat radius for different values of magnetic charges.

Cylindrical asymmetric thin-shell wormholes

By employing certain cylindrically symmetric spacetimes we construct traversable, asymmetric thin-shell wormholes. Specifically, these spacetimes consist of the cosmic string and the 4-dimensional black string metrics. The corresponding thin-shell wormholes are analyzed within the context of linear stability by suppressing the axial perturbations which result in stable asymmetric thin-shell wormholes. Next, we look for a correlation between the stability and the symmetry of the spacetime under investigation which certifies the previous results for spherical thin-shell wormholes, in the sense that the more symmetric a thin-shell wormhole, the more probable to find it in a stable state. However, there is an exceptional case in cosmic strings which is discussed in detail. Furthermore, it is shown that cylindrically symmetric cosmic string wormholes cannot be supported by a barotropic equation of state.

Linearized stability of Bardeen anti-de Sitter wormholes

In this paper, we explore the stable and unstable geometrical structures of thin-shell wormholes. We use Visser cut and paste approach to develop thin-shell from Bardeen anti-de Sitter black holes. The characteristics of matter distribution are determined by using Israel formalism. We discuss the existence of exotic matter at the wormhole throat through energy conditions and examine the attractive/repulsive nature of wormhole throat. The linearized stability of thin-shell is studied through barotropic and variable equations of state (generalized phantomlike and generalized Chaplygin gas model). We conclude that the stability of wormhole depends on the matter distribution as well as cosmological constant. Finally, we compare the stable structure of wormhole for these equations of state through length parameter.

Rotating thin-shell wormholes with scalar field

In this paper, we construct (2 + 1)-dimensional thin-shell wormholes from rotating Bañados–Teitelboim–Zanelli black hole and discuss their stability with the influence of scalar field at thin-shell. We apply Israel thin-shell formalism to evaluate surface stresses and study the behavior of energy conditions. We also study attractive and repulsive characteristics of the respective wormhole configurations according to the direction of radial acceleration. The linearized stability of rotating thin-shell wormholes is analyzed by assuming three different scalar field models at thin-shell. It is found that the increasing rate of angular momentum appears as an effective ingredient for stable wormholes while electric charge does not provide significant results in this regard. We conclude that less massive scalar field yields more stable 3D wormhole solutions.

Stability of Einstein-power-Maxwell (2+1)-dimensional wormholes

This paper is devoted to the study of stable and unstable geometrical structures of charged thin-shell wormholes constructed from Einstein-power-Maxwell black holes by using Visser cut and paste approach. We use Israel thin-shell formalism to evaluate the stress-energy tensor components of matter distribution located at the wormhole throat. The stability of thin-shell is investigated by using equations of state (phantom-like and generalized Chaplygin gas model) for exotic matter and radial perturbation about equilibrium throat radius. We conclude that stable regions increase by increasing the charge parameter.

Thermodynamic stability of a Schwarzschild thin-shell wormhole

The thermodynamic stability of a thin-shell wormhole in a Schwarzschild bulk is considered. From the first law, entropy function is found which satisfies the local intrinsic stability conditions. Heat capacity emerges as a well-defined regular function justifying the stability of a Schwarzschild thin-shell wormhole. Our method applies only to static thin-shell wormholes and in this sense it may be considered as supplementary to the classical method of stability. The scope of applications of the method is not limited by the Schwarzschild wormhole.

Discontinuity problem in the linear stability analysis of thin-shell wormholes

We investigate the infinite discontinuity points of stability diagram in thin-shell wormholes. The square of the speed of sound $\beta _{0}^{2}$,\ which is expressed in terms of pressure and energy density at equilibrium on the throat, arises with a divergent amplitude. As this is physically non-acceptable, \ we revise the equation of state, such that by fine-tuning of the pressure at static equilibrium, which is at our disposal, eliminates such a singularity. The efficacy of the method is shown in Schwarzschild, extremal Reissner-Nordstr\"{o}m, and dilaton thin-shell wormholes.

Thin-shells and thin-shell wormholes in new massive gravity

Within 2 + 1-dimensional cosmological new massive gravity, we consider thin-shell and thin-shell wormhole construction. For this, we introduce first, the junction conditions apt for the fourth order terms in the action of the theory. Then, by employing some specific static solutions in new massive gravity, we study the characteristics of associated thin-shells and thin-shell wormholes. Our finding suggests that, firstly, there cannot exist any thin-shells regarding our chosen solutions of cosmological new massive gravity, and secondly, the constructed thin-shell wormhole does not need to be symmetric. More importantly, the thin-shell wormhole, if ever forms, possesses null energy density and null angular pressure on its throat which are preferable to their negative-valued counterparts.

Nonlinear stability analysis of the Schwarzschild thin-shell wormholes

Eric Poisson and Matt Vissert in their 1995 paper studied the linear stability of the Schwarzschild thin-shell wormholes (STSW). It was shown that for a generic equation of state (EoS) of the form p=pleft( sigma right) on the throat of the wormhole the regions of stability are independent of the explicit form of the surface energy density sigma and the EoS. Here in this work, the nonlinear version of their stability analysis is presented. To do so, three specific EoSs namely a linear, a quadratic and a power law barotropic EoS are considered. For every EoSs, the analytic function of the effective potential is obtained. Finally, the possible motions of the STSW within the corresponding effective potentials are studied.

Thin-shell wormholes from Kiselev black holes

This paper discusses the theoretical construction of thin-shell wormholes from Kiselev black holes. We assume a barotropic equation of state for the exotic matter on the shell. While most of these wormholes are unstable to linearized radial perturbations, a limit argument is used to show that under certain conditions, stable solutions can be found.

Linear stability analysis of evolving thin shell wormholes

Using ideas of cosmological perturbation theories, we make general linear stability analysis of dynamic thin-shell wormholes constructed by cutting-and-pasting two building-block spacetimes at arbitrary joining shell radius. We observed that in appropriate parameter choices, dynamical thin shell wormholes following from such a cut-and-paste procedure can be kept stable during the whole evolution process towards the final extremal point on which the joining shell radius reaches on static values. Our work forms a valuable complementarity to previous analysis basing on virtual spherical perturbations around the born-static configuration of the wormholes.