Higgs quartic coupling and neutrino sector evolution in 2UED models

In this work, we have studied the accretion of dark energies onto a Morris–Thorne wormhole. Previously, in ref. (González-Díaz, arXiv:hep-th/0607137), it was shown that for quintessence like dark energy, the mass of the wormhole decreases, and for phantom like dark energy, the mass of the wormhole increases. We have assumed two types of dark energy: the variable modified Chaplygin gas and the generalized cosmic Chaplygin gas. We have found the expression of the wormhole mass in both cases. We have found the mass of the wormhole at late universe and this is finite. For our choices of the parameters and the function $B(a)$ , these models generate only quintessence dark energy (not phantom) and so the wormhole mass decreases during the evolution of the universe. Next we have assumed the five kinds of parametrizations of well-known dark-energy models. These models generate both quintessence and phantom scenarios i.e., phantom crossing models. So if these dark energies accrete onto the wormhole, then for the quintessence stage, the wormhole mass decreases up to a certain value (a finite value) and then again increases to an infinite value for the phantom stage during whole evolution of the universe. That means that if the five kinds of DE accrete onto a wormhole, the mass of the wormhole decreases up to a certain finite value and then increases in the late stage of the evolution of the universe. We have also shown these results graphically.     

Traversible wormholes in (2 + 1) dimensions

We investigate traversible wormhole solutions to the Einstein field equations in (2 + 1) dimensions. The constraints on the field equations to obtain a wormhole solution are presented and further constraints for traversibility of the wormhole are also given. We show that there is no analog of the (3 + 1)-dimensional Schwarzschild wormhole in (2 + 1) dimensions. For general wormholes, the radial tension and lateral pressure at the throat of the wormhole must be zero, and the energy density must be negative. Two specific wormhole solutions are presented. We perform a stability analysis on the solutions.     

Wavefunction of Wormhole in the Einstein-Yang-Mills Theory

In this paper, the wavefunction of wormhole in the Einstein-Yang-Mills theory is presented by using the method proposed by Hawking. Analysing the wavefunction obtained, we find that the probability density of quantum wormhole at a = 0 is zero and there is the most probable radius for the ground-state wavefunction of wormhole. It indicates that the quantum wormhole is stable.     

Electromagnetic field properties in the vicinity of a massive wormhole

It is proved that not only massless but also traversable massive wormholes can have electromagnetic “hair.” An analysis is also presented of the passage from a traversable wormhole to the limit of a Reissner-Nordström black hole, with the corresponding disappearance of “hair.” A general method is developed for solving stationary axisymmetric Maxwell’s equations in the field of a massive, spherically symmetric wormhole. As a particular example of application of the method, a solution is found to the axisymmetric magnetostatic problem for a current loop in the field of the Bronnikov-Ellis-Morris-Thorne wormhole.     

Stability of Non-asymptotically Flat Thin-Shell Wormholes in Generalized Dilaton-Axion Gravity

We construct a new type of thin-shell wormhole for non-asymptotically flat charged black holes in generalized dilaton-axion gravity inspired by low-energy string theory using cut-and-paste technique. We have shown that this thin shell wormhole is stable. The most striking feature of our model is that the total amount of exotic matter needed to support the wormhole can be reduced as desired with the suitable choice of the value of a parameter. Various other aspects of thin-shell wormhole are also analyzed.     

Classical Euclidean Wormhole Solution and Wave Function for a Nonlinear Scalar Field

In this paper we consider the classical Euclidean wormhole solution of the Born—Infeld scalar field. The corresponding classical Euclidean wormhole solution can be obtained analytically for both very small and large . At the extreme limit of small the wormhole solution has the same format as one obtained by Giddings and Strominger (Nuclear Physics B 306, 890, 1988). At the extreme limit of large the wormhole solution is a new one. The wormhole wave functions can also be obtained for both very small and large . These wormhole wave functions are regarded as solutions of quantum-mechanical Wheeler—Dewitt equation with certain boundary conditions.     

Wormhole supported by dark energy admitting conformal motion

In this article, we study the possibility of sustaining static and spherically symmetric traversable wormhole geometries admitting conformal motion in Einstein gravity, which presents a more systematic approach to search a relation between matter and geometry. In wormhole physics, the presence of exotic matter is a fundamental ingredient and we show that this exotic source can be dark energy type which support the existence of wormhole spacetimes. In this work we model a wormhole supported by dark energy which admits conformal motion. We also discuss the possibility of the detection of wormholes in the outer regions of galactic halos by means of gravitational lensing. Studies of the total gravitational energy for the exotic matter inside a static wormhole configuration are also performed.     

Can wormholes exist?

Renormalized vacuum expectation values of electromagnetic stress-energy tensor are calculated in the background spherically-symmetrical metric of the wormhole topology. The covariant geodesic point separation method of regularization is used. Violation of the weak energy condition at the throat of the wormhole takes place for a geometry sufficiently close to that of an infinitely long wormhole of constant radius irrespective of the detailed from of metric. This is an argument in favour of the possibility of the existence of a self-consistent wormhole in empty space maintained by vacuum field fluctuations in the wormhole's background.     

Wormhole Geometries in f(R,T) Gravity

We study wormhole solutions in the framework of f(R,T) gravity where R is the scalar curvature, and T is the trace of the stress-energy tensor of the matter. We have obtained the shape function of the wormhole by specifying an equation of state for the matter field and imposing the flaring out condition at the throat. We show that in this modified gravity scenario, the matter threading the wormhole may satisfy the energy conditions, so it is the effective stress-energy that is responsible for violation of the null energy condition.     

Thin-Shell Wormholes from Black Holes with Dilaton and Monopole Fields

We provide a new type of thin-shell wormhole from the black holes with dilaton and monopole fields. The dilaton and monopole that built the black holes may supply fuel to construct the wormholes. Several characteristics of this thin-shell wormhole have been discussed. Finally, we discuss the stability of the thin-shell wormholes with a “phantom-like” equation of state for the exotic matter at the throat.     

Nonsymmetric dynamical thin-shell wormhole in Robinson–Trautman class

The thin-shell wormhole created using the Darmois–Israel formalism applied to Robinson–Trautman family of spacetimes is presented. The stress energy tensor created on the throat is interpreted in terms of two dust streams and it is shown that asymptotically this wormhole settles to the Schwarzschild wormhole with a throat located at the position of the horizon. This behavior shows a nonlinear stability (within the Robinson–Trautman class) of this spherically symmetric wormhole. The gravitational radiation emitted by the Robinson–Trautman wormhole during the transition to spherical symmetry is indistinguishable from that of the corresponding black hole Robinson–Trautman spacetime. Subsequently, we show that the higher-dimensional generalization of Robinson–Trautman geometry offers a possibility of constructing wormholes without the need to violate the energy conditions for matter induced on the throat.     

Euclidean non-vacuum wormholes in Brans－Dicke theory

The Brans－Dicke theory is investigated in which the Pauli metric is identified to be a physical spacetime metric. The solutions of a wormhole are obtained in Brans－Dicke theory with a relativistic radiation field for ω>-3/2. However, it is found that one cannot construct a wormhole in the presence of a 3-form axion field.     

具有旋量场的量子虫洞

本文利用Hawking-Page的边界条件讨论了具有费米场的量子虫洞,导出了相应的Wheeler-DeWitt方程,计算了虫洞波函数,由虫洞波函数的分析,发现虫洞在a=0处出现几率密度为零,虫洞基态最可几半径为Planck尺度.     

Wormhole solution in Bergmann-Wagoner scalar-tensor gravitational theory

We give a Euclidean wormhole solution in the vacuum Bergmann-Wagoner scalar-tensor gravitational theory. We show that this wormhole, unlike others, has complex charge and is a baby universe (half a wormhole).     

A positive cosmological constant in string theory through AdS/CFT wormholes

There are two important examples of physical systems which violate the strong energy condition: Universes (like, it would seem, our own) with a positive cosmological constant, and wormholes. We suggest that a positive cosmological constant can be reconciled with string theory by considering wormholes in string backgrounds. This is argued in two directions: first, we show that brane-worlds with positive cosmological constants give rise to bulk singularities which are best resolved by embedding the brane-world in an AdS/CFT wormhole; and second, for the simplest kind of wormhole in an asymptotically AdS space, we show that the IR stability of the matter needed to keep the wormhole open requires the presence of a brane-world. UV stability conditions then forbid a negative cosmological constant on the brane-world.     

Intra-Galactic Thin Shell Wormhole and Its Stability

In this paper, we construct an intra-galactic thin shell wormhole joining two copies of identical galactic space times described by the Mannheim–Kazanas–de Sitter solution in conformal gravity and study its stability under spherical perturbations. We assume the thin shell material as a Chaplygin gas and discuss in detail the values of the relevant parameters under which the wormhole is stable. We study the stability following the method by Eiroa and we also qualitatively analyze the dynamics through the method of Weierstrass. We find that the wormhole is generally unstable but there is a small interval in radius for which the wormhole is stable.     

Self-consistency of the quantum billiard problem in wormhole spacetimes

A wormhole can be made to function as a time machine. In the context of the quantum billiard problem in the presence of a wormhole we examine whether this is compatible with the self-consistency of physics. We derive a self-consistency condition in which the classical limit corresponds to known results for the (classical) billiard problem in a wormhole space-time and that suggests that some fine-tuning of initial conditions might be necessary.