We consider the dynamical Morris-Thorne metric with radiating heat flow. By matching the interior Morris-Thorne metric with an exterior Vaidya metric we trace out the collapse solutions for the corresponding spherically symmetric inhomogeneous distribution of matter. The solutions obtained are broadly of four different types, giving different end state dynamics. Corresponding to three of the solutions we elaborate the collapsing dynamics of the Morris-Thorne type evolving wormhole. We show that for all those cases where collapse upto zero proper volume is obtained in finite time, the ensuing singularity is always a black hole type. However our solutions can also show other end states, like oscillating wormhole-black hole pair or infinite time contracting universe or a conformal past matter dominated universe. In all the cases we have worked out the background dynamics and physics of the solution. All our solutions are illustrated with appropriate graphical descriptions.
Two critical issues in the study of Morris-Thorne wormholes concerns the stability of such structures, as well as their compatibility with quantum field theory. This note discusses an important subset characterized by zero tidal forces. It is shown that such wormholes (1) are in stable equilibrium using a criterion based on the Tolman-Oppenheimer-Volkoff (TOV) equation and (2) are not in direct conflict with quantum field theory.
It is well known that phantom energy, which is characterized by the equation of state $p=ωρ$, $ω<-1$, 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 $p_r=ωρ$, $ω<-1$, where $p_r$ is the radial pressure. Some implications thereof are also considered.
Morris-Thorne wormholes in static pseudo-spherically symmetric spacetimes
本文研究了具有伪球对称性的经典广义相对论静态虫孔位形。我们表明，除了Lobo和Mimoso在参考物理中讨论的双曲虫孔解之外，修订版本\ D { \bf 82}，044034（2010），存在另一种虫孔类，其是球形Morris-Thorne虫孔的真正伪球形对应物（与Lobo-Mimoso虫孔类相反），因为满足了最初由Morris和Thorne为球对称虫孔定义的所有约束。我们发现，对于这两类双曲虫孔的能量密度，在喉，总是负的，而径向压力是积极的，相反的球对称的莫里斯-索恩虫孔。具体的双曲虫孔的构造和讨论施加不同的条件的径向和侧向压力，或通过考虑有限的选择的红移和形状函数。特别是，我们表明，双曲虫洞不能持续在喉部的幻影能量，并有伪球对称的虫洞支持的物质与各向同性的压力，其特征在于空间部分的角度赤字（或过剩）。
The embedding of a curved spacetime in a higher-dimensional flat spacetime has continued to be a topic of interest in the general theory of relativity, as exemplified by the induced-matter theory. This paper deals with spacetimes of embedding class one, i.e., spacetimes that can be embedded in a five-dimensional flat spacetime. Einstein's theory allows the fifth dimension to be either spacelike or timelike. By assuming the latter, this paper addresses two fundamental issues concerning Morris-Thorne wormholes, the origin of exotic matter and the frequently inexplicable enormous radial tension a…
It is well known that a Morris-Thorne wormhole can only be held open by violating the null energy condition, physically realizable by the use of "exotic matter." Unfortunately, even a small or moderately-sized wormhole would have a radial tension equal to that of the interior of a massive neutron star. So outside a neutron-star setting, such an outcome is problematical at best, calling for more than an appeal to exotic matter whose introduction had a completely different objective and with possibly different outcomes. The purpose of this paper is to account for the enormous radial tension in t…
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 non-minimal 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 involve…
We study static traversable wormholes obtained by Morris and Thorne in general relativity (GR) in the framework of a modified theory of gravity. The modified gravitational action $f(R,T)$ is a function of the Ricci scalar ($R$) and of the trace of the energy momentum tensor ($T$). For a modified gravity $f(R,T)=R+αR^{2}+λT$, where $α$ and $λ$ are constants, we obtain wormhole solutions (WH) with normal matter for a relevant shape functions. The energy conditions are checked at the throat and away from the throat of the WH. The coupling parameters $α$ and $λ$ in the gravitational action play an…
Stress-energy tensor of quantized scalar fields in a zero-tidal wormhole
School of Physics and Optoelectronics, South China University of Technology（华南理工大学物理与光电工程学院）；Faculty of Arts and Sciences, Beijing Normal University, Zhuhai（北京师范大学珠海校区文理学院）
Wormholes are outstanding solutions of Einstein's General Relativity. They were worked out in the late 1980's by Morris and Thorne, who have figured out a recipe that wormholes must obey in order to be traversable, that is, safely crossed by travelers. A remarkable feature is that General Relativity Theory wormholes must be filled by {\it exotic matter}, which Morris and Thorne define as matter satisfying $-p_r>ρ$, in which $p_r$ is the radial pressure and $ρ$ is the energy density of the wormhole. In the present article, we introduce, for the first time in the literature, traversable wormhole…
In this work we consider a Generalized Bronnikov-Ellis wormhole and the tideless Morris-Thorne wormhole and we study the propagation of massive scalar fields. We calculate the quasinormal frequencies using the WKB method and the pseudospectal Chebyshev method and we show the presence of an anomalous decay rate for the quasinormal modes in the Generalized Bronnikov-Ellis wormhole. However, such anomalous behaviour is avoided for the fundamental mode in the Morris-Thorne wormhole background.
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.
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 sol…
Natural wormholes and its astrophysical signatures have been sugested in various oportunities. By applying the strong field limit of gravitational lensing theory, we calculate the deflection angle and magnification curves produced by Morris-Thorne wormholes in asimptotically flat space-times. The results show that wormholes act like convergent lenses. Therefore, we show that it is hard to distinguish them from black holes using the deflection's angle of the gravitational lens effect, in contrast with the results reported by Cramer et.al. and Safanova et.al. However, we also show that it is pos…
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 backgroun…
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 asymptotical…
