We discuss new exact solutions of a three-parameter nonminimal Einstein-Maxwell model. The solutions describe static spherically symmetric objects with and without center, supported by an electric field nonminimally coupled to gravity. We focus on a unique one-parameter model, which admits an exact solution for a traversable electrically charged wormhole connecting two universes, one asymptotically flat the other asymptotically de Sitter ones. The relation between the asymptotic mass and charge of the wormhole and its throat radius is analyzed. The wormhole solution found is thus a nonminimal realization of the idea of Wheeler about charge without charge and shows that, if the world is somehow nonminimal in the coupling of gravity to electromagnetism, then wormhole appearance, or perhaps construction, is possible.
We point out that there can be humanly traversable wormhole solutions in some previously considered theories for physics beyond the Standard Model, namely the Randall-Sundrum model.
We obtain traversable wormhole and time machine solutions of the field equations of an alternative of gravity with non-minimally curvature-matter coupling. Our solutions exhibit a non-trivial redshift function and allow for matter that satisfy the dominant energy condition.
We present the gravity description of evaporating black holes that end up with eternal traversable wormholes where every would-be behind horizon degree is available in asymptotic regions. The transition is explicitly realized by a time-dependent bulk solution in the two-dimensional Einstein-dilaton gravity. In this solution, the initial AdS$_2$ black hole is evolved into an eternal traversable wormhole free of any singularity, which may be dubbed as transparentization of black holes to eternal traversable wormholes. The bulk construction completely matches with the boundary description governe…
In this work we show the existence of traversable wormhole and time-machine solutions in a modified theory of gravity where matter and curvature are nonminimally coupled. Those solutions present a nontrivial redshift function and exist even in the presence of ordinary matter which satisfies the dominant energy condition.
We construct an eternal traversable wormhole connecting two asymptotically $\text{AdS}_4$ regions. The wormhole is dual to the ground state of a system of two identical holographic CFT's coupled via a single low-dimension operator. The coupling between the two CFT's leads to negative null energy in the bulk, which supports a static traversable wormhole. As the ground state of a simple Hamiltonian, it may be possible to make these wormholes in the lab or on a quantum computer.
We attempt to construct eternal traversable wormholes connecting two asymptotically AdS regions by introducing a static coupling between their dual CFTs. We prove that there are no semiclassical traversable wormholes with Poincaré invariance in the boundary directions in higher than two spacetime dimensions. We critically examine the possibility of evading our result by coupling a large number of bulk fields. Static, traversable wormholes with less symmetry may be possible, and could be constructed using the ingredients we develop here.
We study traversable Lorentzian wormholes in the three-dimensional low energy string theory by adding some matter source involving a dilaton field. It will be shown that there are two-different types of wormhole solutions such as BTZ and black string wormholes depending on the dilaton backgrounds, respectively. We finally obtain the desirable solutions which confine exotic matter near the throat of wormhole by adjusting NS charge.
We compare the effects of Noncommutative Geometry and Gravity's Rainbow on traversable wormholes which are sustained by their own gravitational quantum fluctuations. Fixing the geometry on a well tested model, we find that the final result shows that the wormhole is of the Planckian size. This means that the traversability of the wormhole is in principle, but not in practice.
In this letter, we introduce the astrophysical observations into the wormhole research, which is not meant to general parameters constraints for the dark energy models, in order to understand more about in which stage of the universe evolutions wormholes may exist through the investigation of the evolution behavior of the cosmic equation of state parameter. As a concrete instance, we investigate the Ricci dark energy (RDE) traversable wormholes constrained by astrophysical data-sets. Particularly, we can discover from Fig. \ref{fig5} of the present work, when the effective equation of state pa…
In this letter we point out the existence of solutions to General Relativity with a negative cosmological constant in four dimensions, which contain solitons as well as traversable wormholes. The latter connect two asymptotically locally AdS$_{4}$ spacetimes. At every constant value of the radial coordinate the spacetime is a spacelike warped AdS$_{3}$. We compute the dual energy momentum tensor at each boundary showing that it yields different results. We also show that these vacuum wormholes can have more than one throat and that they are indeed traversable by computing the time it takes for…
Bubble universes and traversable wormholes in general relativity can be realized as two sides of the same concept. To exemplify, we find, display, and study in a unified manner a Minkowski-Minkowski closed universe and a Minkowski-Minkowski traversable wormhole. By joining two 3-dimensional flat balls along a thin shell two-sphere of matter, i.e., a spherical domain wall, into a single spacetime one gets a Minkowski-Minkowski static closed universe, i.e., a bubble universe. By joining two 3-dimensional complements of flat balls along a thin shell two-sphere of matter, i.e., a spherical throat,…
We present a wormhole solution in four dimensions. It is a solution of an Einstein Maxwell theory plus charged massless fermions. The fermions give rise to a negative Casimir-like energy, which makes the wormhole possible. It is a long wormhole that does not lead to causality violations in the ambient space. It can be viewed as a pair of entangled near extremal black holes with an interaction term generated by the exchange of fermion fields. The solution can be embedded in the Standard Model by making its overall size small compared to the electroweak scale.
In this letter, we investigate the traversable wormholes in the holographic dark energy (HDE) model constrained by the modern astronomical observations. First of all, we constrain the HDE model by adopting different data-sets, explore the cosmological background evolution of the HDE model, and find that the HDE model will be fitting better than the Ricci dark energy (RDE) model for the same SNe Ia data-sets by using the the so-called Akaike Information Criterions (AIC) and Bayesian Information Criterions (BIC) . Furthermore, we discover that if taking the SNe Ia data-sets, the wormholes will a…
We compute the graviton one loop contribution to a classical energy in a traversable wormhole background. Such a contribution is evaluated by means of a variational approach with Gaussian trial wave functionals. A zeta function regularization is involved to handle with divergences. A renormalization procedure is introduced and the finite one loop energy is considered as a self-consistent source for the traversable wormhole.
Traversable Wormhole are amazing astrophysical objects predicted by General Relativity which are able to connect remote region of space-time. Even if their existence has not been proved yet they are object of continuous investigation. From the theoretically point of view, to exist, traversable wormholes need a special form of energy density termed exotic. Since this exotic source must be concentrated on the throat of the wormhole, we discuss the implications of assuming Yukawa-like profiles which could be realize such a configuration.
It was argued in literature that traversable wormholes can exist with arbitrarily small violation of null energy conditions. We show that if the amount of exotic material near the wormhole throat tends to zero, either this leads to a horn instead of a wormhole or the throat approaches the horizon in such a way that infnitely large stresses develop on the throat.
In this work, we explore the connection between Casimir energy and an Absurdly Benign Traversable Wormhole, which in the literature has been considered only in the pioneering paper of Morris and Thorne. To have consistency with the Casimir source, we need to generalize the idea of an Absurdly Benign Traversable Wormhole into a Generalized Absurdly Benign Traversable Wormhole. With this generalization, we have found that the wormhole throat is not more Planckian, but huge. Three profiles have been studied: one of them is directly connected with the Casimir source, while the other two have been …
We investigate a nucleation of a Euclidean wormhole and its analytic continuation to Lorentzian signatures in Gauss-Bonnet-dilaton gravity, where this model can be embedded by the type-II superstring theory. We show that there exists a Euclidean wormhole solution in this model by choosing a suitable shape of the dilaton potential. After the analytic continuation, this explains a quantum creation of a time-like traversable wormhole. Finally, we discuss relations to the information loss problem and the current literature.
The massless conformally coupled scalar field is characterized by the so-called "new improved stress-energy tensor", which is capable of classically violating the null energy condition. When coupled to Einstein gravity we find a three-parameter class of exact solutions. These exact solutions include the Schwarzschild geometry, assorted naked singularities, and a large class of traversable wormholes.
Dark matter halos are common in galaxies and globular clusters, making it possible to use dark matter density profiles to construct transverse wormholes. In reference [1], an approximate solution of the traversable wormhole satisfying the isotropic pressure condition is constructed by using the dark matter density profile. However, approximate solutions limit the discussion of traversable wormholes to a large extent. In this work, we construct the exact solution of the traversable wormhole in the case of rotation in the dark matter halo. We have written analytical expressions for the Kerr-like…
Asymptotically flat wormhole solutions are found in the deformed Hořava-Lifshitz gravity. It turns out that higher curvature terms can not play the role of exotic matters which are crucial to form a traversable wormhole, and external exotic sources are still needed. In particular, the exotic matter behaves like phantom energy if Kehagias-Sfetsos vacuum is considered outside the wormhole. Interestingly, the spherically symmetric setting makes the matter and the higher curvature contribution satisfy four-dimensional conservation of energy in the covariant form.
We have proposed a novel shape function on which the metric that models traversable wormholes is dependent. Using this shape function, the energy conditions, equation of state and anisotropy parameter are analyzed in $f(R)$ gravity, $f(R,T)$ gravity and general relativity. Furthermore, the consequences obtained with respect to these theories are compared. In addition, the existence of wormhole geometries is investigated.
Traversable wormholes have traditionally been viewed as intrinsically topological entities in some multiply connected spacetime. Here, we show that topology is too limited a tool to accurately characterize a generic traversable wormhole: in general one needs geometric information to detect the presence of a wormhole, or more precisely to locate the wormhole throat. For an arbitrary static spacetime we shall define the wormhole throat in terms of a 2-dimensional constant-time hypersurface of minimal area. (Zero trace for the extrinsic curvature plus a "flare-out" condition.) This enables us to …
In this work we construct traversable wormholes geometries in the framework of the complexity factor. We provide the redshift function of a Casimir traversable wormhole which, in combination with a non--vanishing complexity factor, leads to a traversable wormhole with a minimum amount of exotic matter. The shape function and the embedding diagram are shown and discussed. The tidal accelerations and the time required to get through the wormholes are estimated.
We argue that one can nucleate a traversable wormhole via a nonperturbative process in quantum gravity. To support this, we construct spacetimes in which there are instantons giving a finite probability for a test cosmic string to break and produce two particles on its ends. One should be able to replace the particles with small black holes with only small changes to the spacetime away from the horizons. The black holes are then created with their horizons identified, so this is an example of nucleating a wormhole. Unlike previous examples where the created black holes accelerate apart, in our…
In the letter titled ''Traversable Wormholes in General Relativity'' [Phys. Rev. Lett. 128, 091104 (2022)], R. A. Konoplya and A. Zhidenko have constructed an asymmetric wormhole solution, which is not symmetric about the throat and is compounded from smooth gravitational and charged Dirac fields. However, the authors have claimed that a physically relevant condition on the throat is imposed to lead to no gravitational force experienced by a stationary observer at the throat. In this comment, we point out that the above condition is unnecessary.
In this paper, we study the perturbation problem of the scalar, electromagnetic, and gravitational waves under the traversable Lorentzian wormhole geometry. The unified form of the potential for the Schrödinger type one-dimensional wave equation is found.
We construct detailed AdS$_2$ gravity solutions describing the teleportation through a traversable wormhole sending a state from one side of the wormhole to the other. The traversable wormhole is realized by turning on a double trace interaction that couples the two boundaries of an eternal AdS$_2$ black hole. The horizon radius or the entropy of the black hole is reduced consistently with the boundary computation of the energy change, confirming the black hole first law. To describe teleportee states traveling through the wormhole, we construct Janus deformations which make the Hamiltonians o…
We consider static spherically symmetric wormhole configurations in a gravitational theory of a scalar field with a potential $V(ϕ)$ and nonminimal derivative coupling to the curvature describing by the term $(εg_{μν} + κG_{μν}) ϕ^{,μ}ϕ^{,ν}$ in the action. We show that the flare-out conditions providing the geometry of a wormhole throat could fulfilled both if $ε=-1$ (phantom scalar) and $ε=+1$ (ordinary scalar). Supposing additionally a traversability, we construct numerical solutions describing traversable wormholes in the model with arbitrary $κ$, $ε=-1$ and $V(ϕ)=0$ (no potential). The tr…
We study the scattering of low-energy massless and massive minimally coupled scalar fields by an asymptotically flat traversable wormhole. We provide a comprehensive treatment of this problem offering analytic expressions for the transmission and reflection amplitudes of the corresponding effective potential and the absorption cross section of the wormhole. Our results, which are based on a recently developed dynamical formulation of time-independent scattering theory, apply to a large class of wormhole spacetimes including a wormhole with a sharp transition, the Ellis wormhole, and a family o…
We study the Lorentzian static traversable wormholes coupled to quadratic scalar fields. We also obtain the solutions of the scalar fields and matters in the wormhole background and find that the minimal size of the wormhole should be quantized under the appropriate boundary conditions for the positive non-minimal massive scalar field.
We propose possible probes which could be used to demonstrate experimentally the existence of the bulk and the formation of a traversable wormhole purely in terms of boundary operations only. In the two-dimensional Einstein-dilaton gravity, the traversable wormhole is realized by turning on a double trace interaction which couples the two boundaries of the AdS$_2$ black hole. Signals can propagate in the traversable wormhole through two different channels. The boundary channel is direct and instantaneous, while the bulk channel respects the bulk causality and takes a certain amount of time to …
It is shown in this paper that it is possible, at least in principle, to construct a traversable wormhole that is stable to linearized radial perturbations by specifying relatively simple conditions on the shape and redshift functions.
We describe the construction of traversable wormholes with multiple mouths in four spacetime dimensions and discuss associated quantum entanglement. Our wormholes may be traversed between any pair of mouths. In particular, in the three-mouth case they have fundamental group $F_2$ (the free group on two generators). By contrast, connecting three regions $A,B,C$ in pairs ($AB$, $BC$, and $AC$) using three separate wormholes would give fundamental group $F_3$. Our solutions are asymptotically flat up to the presence of possible magnetic fluxes or cosmic strings that extend to infinity. The constr…
In this paper, we evaluate traversable wormhole solutions through Karmarkar condition in $f(R,T)$ theory, where $T$ is the trace of the energy-momentum tensor and $R$ represents the Ricci scalar. We develop a wormhole shape function for the static traversable wormhole geometry by using the embedding class-I technique. The resulting shape function is used to construct wormhole geometry that fulfills all the necessary conditions and joins the two asymptotically flat regions of the spacetime. We investigate the existence of viable traversable wormhole solutions for anisotropic matter configuratio…
We construct traversable wormholes by starting with simple four-dimensional classical solutions respecting the null energy condition and containing a pair of oppositely charged black holes connected by a non-traversable wormhole. We then consider the perturbative back-reaction of bulk quantum fields in Hartle-Hawking states. Our geometries have zero cosmological constant and are asymptotically flat except for a cosmic string stretching to infinity that is used to hold the black holes apart. Another cosmic string wraps the non-contractible cycle through the wormhole, and its quantum fluctuation…
We consider the effects of Gravity's Rainbow on the self-sustained equation which is responsible to find new traversable wormholes configurations which are sustained by their own gravitational quantum fluctuations. The same self-sustained equation is also used to discover if topology change is possible. In this contribution, we will show that in both uses, the self-sustained equation will produce a Wheeler wormhole, namely a wormhole of Planckian size. This means that, from the point of view of traversability, the wormhole will be traversable in principle, but not in practice. From the topolog…
We show explicitly that traversable wormholes requiring exotic matter in 4-dimensions nevertheless have acceptable stress-tensors obeying reasonable energy conditions in higher dimensions if the wormholes are regarded as being embedded in higher dimensional space-times satisfying Einstein's field equations. From the 4-dimensional perspective, the existence of higher dimensions may thus facilitate wormhole and time-machine constructions through access to "exotic matter".
Potentiality of the presence of traversable wormholes in the outer/inner regions of the halos of galaxies, situated on the Navarro-Frenk-White (NFW) density profile and Universal Rotation Curve (URC) dark matter models have been investigated recently. Since this covers our own galaxy also as a possible home for traversable wormholes it prompts us to further the subject by considering alternative density distributions. From this token herein we make use of the Einasto model to describe the density profiles for the same purpose. Our choice for the latter is based on the fact that theoretical dar…
The theoretical construction of a traversable wormhole from a Schwarzschild black hole is described, using analytic solutions in Einstein gravity. The matter model is pure phantom radiation (pure radiation with negative energy density) and the idealization of impulsive radiation is employed.
We consider the effects of Gravity's Rainbow on the self-sustained equation which is responsible to find new traversable wormholes configurations powered by their own gravitational quantum fluctuations. The form of the shape function considered is obtained by imposing the equation of state $p_{r}=ωρ$. We investigate the size of the wormhole as a function of the parameter $ω$ in the phantom region. We discover that a wormhole which is traversable in principle, but not in practice, can be produced.
A self--sustained traversable wormhole is obtained as a vacuum solution of a scale-dependent gravitational theory. Comparison with other approaches towards wormhole self--sustainability are presented, with emphasis on the running of the gravitational coupling and on a possible effective description of gravity near the Planck scale.
We obtain a static spherically symmetric wormhole solution due to the vacuum expectation value (VEV) of a Kalb-Ramond field. The Kalb-Ramond VEV is a background tensor field which produces a local Lorentz symmetry breaking (LSB) of spacetime. Considering a non-minimal coupling between the Kalb-Ramond (VEV) and the Ricci tensor, we found an exact traversable wormhole solution sustained by matter sources with a negative isotropic pressure. The matter source satisfies the energy conditions at the throat for particular choices of the LSB parameter. Moreover, we employ the Gauss-Bonnet method to an…
Analytic solutions are presented which describe the construction of a traversable wormhole from a Schwarzschild black hole, and the enlargement of such a wormhole, in Einstein gravity. The matter model is pure radiation which may have negative energy density (phantom or ghost radiation) and the idealization of impulsive radiation (infinitesimally thin null shells) is employed.
We study four coupled SYK models and nearly AdS$_2$ gravities. In the SYK model side, we construct a model that couples two copies of two coupled SYK models. In nearly AdS$_2$ gravity side, we entangle matter fields in two copies of traversable wormholes. In both cases, the systems show first order phase transitions at zero temperature by changing couplings, which is understood as the exchange of traversable wormhole configurations. In nearly AdS$_2$ gravity cases, by exchanging the role of space and time the wormholes are interpreted as bra-ket wormholes. In Lorentzian signature, these bra-ke…
The purpose of this paper is to obtain exact solutions of the Einstein field equations describing traversable wormholes supported by phantom energy. Their relationship to exact solutions in the literature is also discussed, as well as the conditions required to determine such solutions.
Casimir energy is always indicated as a potential source to generate a Traversable Wormhole. It is also used to proof the existence of negative energy which can be built in the laboratory. However, in the scientific literature there is no trace of the consequences on the traversable wormhole itself. In this work, we would like to consider such a source to see if and which kind of traversable wormhole can be produced. As a further analysis, we examine also the consequences of Quantum Weak Energy Conditions on the traversability of the wormhole. We find that an agreement with the original Casimi…
This study aims to investigate the viability of a viable logarithmic f(R) gravity for inflation in giving wormhole solutions. We consider a static and spherically symmetric spacetime and two different shape functions. We found that the model provides traversable wormhole solutions shown by its violation to energy conditions. Violation to null energy condition indicates the existence of traversable wormhole and the existence of exotic matter. The equation of state parameter is less than -1 which shows the presence of phantom fluid. Furthermore, the stability of wormhole is analyzed using Tolman…
We construct a specific example of a class of traversable wormholes in Einstein-Dirac-Maxwell theory in four spacetime dimensions, without needing any form of exotic matter. Restricting to a model with two massive fermions in a singlet spinor state, we show the existence of spherically symmetric asymptotically flat configurations which are free of singularities, representing localized states. These solutions satisfy a generalized Smarr relation, being connected with the extremal Reissner-Nordström black holes. They also possess a finite mass $M$ and electric charge $Q_e$, with $Q_e/M>1$. An ex…
In this paper we study traversable wormholes in the context of $f(R)$ gravity. Exact solutions of traversable wormholes are found by imposing the nonconstant Ricci scalar. These solutions asymptotically match spherical, flat and hyperbolic FRW metric. By choosing some static $f(R)$ gravity models, we verify the standard energy conditions for the asymptotically spherical, flat and hyperbolic wormhole solutions. Unlike the Einstein gravity, we find that in the context of $f(R)$ modified gravity, the asymptotically spherical, flat and hyperbolic wormhole solutions can respect the null energy cond…
