虫洞的生成函数
Mod. Phys. Lett. A
Pub Date : 2019-01-07
DOI : 10.1142/s021773231950010x
Farook Rahaman 1 , Susmita Sarkar 1 , Ksh. Newton Singh 1,2 , Neeraj Pant 3
Affiliations
Department of Mathematics, Jadavpur University, Kolkata 700032, West Bengal, India
Department of Physics, National Defence Academy, Khadakwasla, Pune, India
Department of Mathematics, National Defence Academy, Khadakwasla, Pune 411023, India
众所周知，虫洞几何可以通过容忍违反零能量条件 (NEC) 来解决爱因斯坦场方程。物理物质分布不可能违反 NEC，但是，可以通过考虑“外来物质”的分布来实现。这项工作的主要目的是找到包含类似虫洞几何形状的生成函数，并讨论这些生成函数的性质。我们使用了 Herrera 等人。[物理。Rev. D 77, 027502 (2008)] 在虫洞时空背景下获得生成函数的方法。在这里，我们采用了两种方法来求解场方程以找到虫洞几何形状。在第一种方法中，我们假设红移函数 f(r) 和形状函数 b(r) 并求解生成函数。在另一次尝试中。

D维可穿越的卡西米尔虫洞
Mod. Phys. Lett. A
Pub Date : 2022-06-15
DOI : 10.1142/s0217732322500900
P. H. F. Oliveira 1 , G. Alencar 1 , I. C. Jardim 2 , R. R. Landim 1
Affiliations
Departamento de Física, Universidade Federal do Ceará, Fortaleza 60455-760, Ceará, Brazil
Departamento de Física, Universidade Regional do Cariri, Juazeiro do Norte 63040-000, Brazil
虫洞 (WH) 需要负能量，因此是外来物质源。由于卡西米尔能量是负的，很久以前它就被推测为获取这些物体的良好候选者。然而，直到最近，一个完整的解决方案D = 4已被 [R. 加拉蒂尼，欧元。物理。J.C 79, 951 (2019), doi:10.1140/epjc/s10052-019-7468-y] 因此，Casimir 能量可以成为可穿越 WH 的来源。不久之后 [G. Alencar、V. B. Bezerra 和 C. R. Muniz，arXiv:2104.13952[gr-qc]] 已经表明，这在D = 3. 在本文中，我们表明卡西米尔能量可以成为所有时空的莫里斯-索恩 WH 的来源D > 3. 最后，我们加上宇宙常数，发现对于D = 3Casimir WH 是可能的，但是，空间必须始终是 AdS。为了D > 3，我们表明宇宙学常数会随着喉部尺寸的增加而反转信号。

标量多虫洞
Classical Quant. Grav.
Pub Date : 2016-08-05
DOI : 10.1088/0264-9381/33/17/175011
A I Egorov , P E Kashargin , Sergey V Sushkov
1921 年巴赫和外尔推导出叠加的方法来构造广义相对论的新轴对称真空解。在本文中，我们将 Bach-Weyl 方法扩展到具有无质量标量场的非真空配置。考虑到具有负动能的幻影标量场，我们构建了一个多虫洞解决方案，描述了 $N$ 虫洞的轴对称叠加。找到的解决方案是静态的，到处都是规则的，没有事件视界。这些特征从其他轴对称真空解决方案中彻底区分了多虫洞配置，这些解决方案不可避免地包含重力惰性的奇异结构，例如“支柱”和“膜”，使两个物体分开形成稳定的配置。然而，多虫洞是静态的，没有任何单一的支柱。反而，多虫洞配置的平稳性由具有负动能的幻影标量场提供。另一个不寻常的特性是多虫洞时空具有复杂的拓扑结构。也就是说，在时空中存在着$2^N$个由喉道相连的渐近平坦区域。

深入遍历虫洞
Fortschr. Phys.
Pub Date : 2017-05-01
DOI : 10.1002/prop.201700034
Juan Maldacena 1 , Douglas Stanford 1 , Zhenbin Yang 2
Affiliations
Institute for Advanced Study Princeton NJ 08540 USA
Jadwin Hall Princeton University Princeton NJ 08540 USA
我们研究了虫洞的各个方面，这些虫洞通过两个渐近边界之间的相互作用而变得可遍历。我们专注于接近AdS2重力的情况，并讨论了有关重力动力学的非常简单的机械图。我们为两侧相关器推导了一个公式，其中包括重力反作用的影响，这限制了我们可以通过虫洞发送的信息量。我们强调，该过程可以看作是一个传送协议，在该协议中，传送者穿过虫洞不会感到什么特别的事情。我们讨论了一些针对旧黑洞的克隆悖论的应用。我们指出，关于AdS2引力得出的相同公式对于简单的SYK量子力学理论，在热场双态附近也是有效的。我们从运营商增长模型的角度对这种现象进行了启发式描述。最后，我们证明了在具有大量自由度的完全经典的混沌系统中也存在类似的效果。

多口可穿越的虫洞
J. High Energy Phys.
Pub Date : 2021-05-05
DOI : 10.1007/jhep05(2021)032
Roberto Emparan , Brianna Grado-White , Donald Marolf , Marija Tomašević
我们在四个时空维度上描述了具有多个嘴的可穿越虫洞的构造，并讨论了相关的量子纠缠。我们的虫洞可以在任何一对嘴之间穿行。特别是在三嘴情况下，它们具有基本群F 2（两个发电机上的自由群）。相比之下，使用三个单独的虫洞成对地连接三个区域A，B，C（AB，BC和AC）将得到基本群F 3。。我们的解决方案在渐近趋近于可能延伸到无穷大的可能的磁通量或宇宙弦的情况下趋于平坦。该构造始于一个两口可穿越的虫洞，该虫洞由量子场的反向反应支撑。在其喉咙中插入足够小的黑洞可保留原始两个嘴之间的可遍历性。这个黑洞被认为是另一个蠕虫的嘴巴，它将原来的喉咙连接到了一个新的时空遥远区域。使新的虫洞以与原始的两口虫洞类似的方式可遍历，可以提供所需的因果关系。从双场理论的观点来看，当将AdS渐近性添加到我们的构造中时，多方纠缠可能在所产生的虫洞的可遍历性中发挥重要作用。
该文章的预印本可在ArXiv上获得。
查看原文 公开下载
英文标题摘要

Multi-mouth traversable wormholes
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 F2 (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 F3. Our solutions are asymptotically flat up to the presence of possible magnetic fluxes or cosmic strings that extend to infinity. The construction begins with a two-mouth traversable wormhole supported by backreaction from quantum fields. Inserting a sufficiently small black hole into its throat preserves traversability between the original two mouths. This black hole is taken to be the mouth of another wormhole connecting the original throat to a new distant region of spacetime. Making the new wormhole traversable in a manner similar to the original two-mouth wormhole provides the desired causal connections. From a dual field theory point of view, when AdS asymptotics are added to our construction, multiparty entanglement may play an important role in the traversability of the resulting wormhole.
A preprint version of the article is available at ArXiv.

旋转薄壳虫洞
Eur. Phys. J. Plus
Pub Date : 2016-11-08
DOI : 10.1140/epjp/i2016-16389-6
A. Ovgun
我们使用Darmois-Israel结条件，在五个维度上使用Myers-Perry黑洞构造了一个旋转的薄壳虫洞。在扰动下分析虫洞的稳定性。我们发现虫洞的喉咙需要异物才能保持其稳定。我们的分析表明，如果选择合适的参数值，则旋转薄壳虫孔的稳定性是可能的。
查看原文 公开下载
英文标题摘要
Rotating thin-shell wormhole
We construct a rotating thin-shell wormhole using a Myers-Perry black hole in five dimensions, using the Darmois-Israel junction conditions. The stability of the wormhole is analyzed under perturbations. We find that exotic matter is required at the throat of the wormhole to keep it stable. Our analysis shows that stability of the rotating thin-shell wormhole is possible if suitable parameter values are chosen.

来自量子引力坍缩的彩虹黑洞
Phys. Rev. D
Pub Date : 2022-04-06
DOI : 10.1103/physrevd.105.086002
Aliasghar Parvizi , Tomasz Pawłowski , Yaser Tavakoli , Jerzy Lewandowski
标量场模式在坍缩均匀尘埃球的量子时空中传播的量子演化被有效地写为相同量子模式在（半经典）修饰几何上的演化。当场的逆反应被丢弃时，经典时空奇点由于量子引力效应而被解决，并被修饰塌陷背景上的量子反弹所取代。在存在逆反应的情况下，出现的（内部）修整几何形状变得依赖于模式，并且与每个模式的逆反应相关的能量密度与辐射流体的比例相同。这种所谓彩虹的半经典动力学穿着背景进行分析。事实证明，与仅存在粉尘流体的情况相比，反向反应效应加速了反弹的发生。通过匹配尘埃边界的内部和外部区域，一个依赖模式的黑洞几何形状作为外部时空出现。讨论了这种彩虹黑洞的性质。这种模式依赖性尤其会导致引力透镜过程中的色差，通过计算所谓的爱因斯坦角来估计其最大值。

Rainbow black hole from quantum gravitational collapse
Quantum evolution of a scalar field’s modes propagating on quantum spacetime of a collapsing homogeneous dust ball is written effectively as an evolution of the same quantum modes on a (semiclassical) dressed geometry. When the backreaction of the field is discarded, the classical spacetime singularity is resolved due to quantum gravity effects and is replaced by a quantum bounce on the dressed collapse background. In the presence of backreaction, the emergent (interior) dressed geometry becomes mode dependent, and the energy density associated with the backreaction of each mode scales as a radiation fluid. Semiclassical dynamics of this so-called rainbow dressed background is analyzed. It turns out that the backreaction effects speed up the occurrence of the bounce in comparison to the case where only a dust fluid is present. By matching the interior and exterior regions at the boundary of dust, a mode-dependent black hole geometry emerges as the exterior spacetime. Properties of such a rainbow black hole are discussed. That mode dependence causes, in particular, a chromatic aberration in the gravitational lensing process of which maximal magnitude is estimated via calculation of the so-called Einstein angle.

穿越虫洞的物质
Phys. Rev. D
Pub Date : 2022-11-29
DOI : 10.1103/physrevd.106.104054
Karina Calhoun, Brendan Fay, Ben Kain
我们重新审视了 Ellis-Bronnikov-Morris-Thorne 虫洞的数值演化，这些虫洞由无质量的真实幽灵标量场构成。对于我们的模拟，我们开发了一个基于标准的新代码3个+1个时空的叶状结构。我们确认，对于无质量对称虫洞，规则标量场脉冲会导致虫洞喉部坍塌并形成视界，而幽灵标量场脉冲会导致虫洞喉部扩大。作为一个新的结果，我们证明了常规物质的脉冲有可能穿过虫洞，然后在虫洞坍塌之前发回光信号。我们还进化出穿过巨大的不对称虫洞的物质脉冲，这在以前从未被模拟过。

英文标题摘要
Matter traveling through a wormhole
We revisit the numerical evolution of Ellis-Bronnikov-Morris-Thorne wormholes, which are constructed with a massless real ghost scalar field. For our simulations, we have developed a new code based on the standard 3+1 foliation of spacetime. We confirm that, for the massless symmetric wormhole, a pulse of regular scalar field causes the wormhole throat to collapse and form an apparent horizon, while a pulse of ghost scalar field can cause the wormhole throat to expand. As a new result, we show that it is possible for a pulse of regular matter to travel through the wormhole and then to send a light signal back before the wormhole collapses. We also evolve pulses of matter traveling through massive asymmetric wormholes, which has not previously been simulated.

粘性宇宙中的虫洞
Phys. Dark Universe
Pub Date : 2021-12-29
DOI : 10.1016/j.dark.2021.100944
Deng Wang 1
Affiliations
我们研究了粘性宇宙中当前的静态和球对称虫洞时空配置。考虑三类粘性模型，即体积粘性作为哈勃常数的函数H0, 目前的宇宙温度 吨0 和暗能量密度 ρ0，分别得到几个虫洞解。通过对各向异性解的分析，我们得出结论，在某种程度上，这三类粘性模型相互之间具有很高的简并性，与理想的流体结果略有偏差。随后，不失一般性，为了研究虫洞解的可穿越性、能量条件和稳定性，我们研究了粘性常数红移函数的虫洞解。ω具有恒定体积粘度系数的 CDM 模型。我们得到以下结论：横移速度值随着体积黏度的降低而减小，并且旅行者的横移速度不仅取决于虫洞的几何形状，还取决于宇宙学背景演化的影响；当体积黏度或宇宙膨胀速度降低时，零能条件被更明显地违反；对于正表面能密度的情况，结半径的范围减小，参数值λ 当虫洞的喉道半径被进一步限制时 r0/米 增加，体积粘度系数 ζ0 减少和现在的哈勃参数 H0分别减少；对于负表面能密度的情况，通过增加r0/米, 递减 ζ0 并且增加 H0, 参数值 λ 限制较少，可以得出结论，总稳定区域增加，结半径的范围分别增加，增加和减少。

Wormholes in a viscous universe
We study the static and spherically symmetric wormhole spacetime configurations at present time in a viscous universe. Considering three classes of viscous models, i.e., bulk viscosity as a function of Hubble constant H0, present cosmic temperature T0 and dark energy density ρ0, respectively, we obtain several wormhole solutions. Through the analysis for the anisotropic solutions, we conclude that, to some extent, these three classes of viscous models have very high degeneracy with each other, and deviate slightly from the ideal fluid consequence. Subsequently, without the loss of generality, to investigate the traversabilities, energy conditions and stability for the wormhole solution, we study the wormhole solution of the constant redshift function of the viscous ωCDM model with a constant bulk viscosity coefficient. We obtain the following conclusions: the value of traversal velocity decreases for decreasing bulk viscosity, and the traversal velocity for a traveler depends on not only the wormhole geometry but also the effects of cosmological background evolution; the null energy condition will be violated more clearly when the bulk viscosity or the cosmic expansion velocity decreases; for the case of a positive surface energy density,

the range of the junction radius decreases and the values of the parameter λ are further restricted when the throat radius of the wormhole r0/M increases, bulk viscosity coefficient ζ0 decreases and present-day Hubble parameter H0 decreases, respectively; for the case of a negative surface energy density, by increasing r0/M, decreasing ζ0 and increasing H0, the values of the parameter λ are less restricted, one may conclude that the total stability region increases, and the range of the junction radius increases, increases and decreases, respectively.