近日，南非夸祖鲁-纳塔尔大学的Ayan Banerjee及其研究小组与印度GLA大学的Anirudh Pradhan合作并取得一项新进展。经过不懈努力，他们对暗能量对于可穿越虫洞可持续性的必要性进行研究。相关研究成果已于2025年1月15日在《中国物理C》上发表。

据悉，暗能量通常是虫洞（WH）可穿越性所需的主要成分，因为它提供了保持虫洞喉部开放所需的负引力效应。然而，这是否能在没有暗能量的情况下实现呢？

事实证明，如果将能量-动量张量的迹与标准爱因斯坦-希尔伯特拉格朗日量耦合，并采用特定的状态方程（EoS），就可能无需暗能量。众所周知，卡西米尔应力能量会导致能量-动量张量违反零能量条件（NEC）。这一现象使得该状态方程成为生成可穿越虫洞几何结构的理想选择。这一已在实验室得到证实的现象提供了一种自然机制，能够在不依赖暗能量的情况下维持开放的虫洞喉部。因此，研究人员在能量-动量迹耦合引力理论中生成了两类虫洞解。

通过选择特定的卡西米尔状态方程（关联能量-动量张量分量，参见Kar和Sahdev: Phys. Rev. D 52, 2030 (1995)）和不同的红移函数，研究人员完全确定了虫洞的几何结构。所得虫洞解违反了零能量条件，并且满足了物理上可实现的虫洞所需的所有定性约束。研究人员通过为耦合参数选择适当范围并绘制图形来展示了这一点。此外，这项研究还探讨了引力的排斥效应，揭示出其存在会导致沿零测地线传播的光子产生负偏转角。值得注意的是，在考虑的三种情景中，研究人员观察到偏转角在所有r₀值下均保持一致为负，从而清晰地表明了引力排斥效应的存在。而这一切都是在不引入暗能量的情况下实现的。

此外，他们的研究调查了重力的排斥效应，揭示了它的存在导致光子沿零测地线行进的负偏转角。值得注意的是，该研究团队观察到在考虑的三种情况下，所有r0值的偏转角都是负值，这表明了排斥引力效应的明显表现。所有这些都是可能的，而不需要暗能量的存在。

附：英文原文

Title: Is dark energy necessary for the sustainability of traversable wormholes

Author: Ayan Banerjee, Sudan Hansraj, Anirudh Pradhan, Abdelghani Errehymy

Issue&Volume: 2025-01-15

Abstract: Dark energy is typically the principal component needed for the traversability of wormholes (WH), as it provides the negative gravity effect required to keep the throat open. However, can this be achieved without dark energy It turns out that if we couple the trace of energy-momentum with the standard Einstein-Hilbert Lagrangian and utilize a specific equation of state (EoS), dark energy may be obviated. The Casimir stress energy is known to result in the violation of the null energy condition (NEC) on the energy momentum tensor. This phenomenon makes such an EoS an ideal candidate for generating traversable WH geometries. The laboratory proven phenomenon provides a natural mechanism to sustain an open WH throat without relying on dark energy. Therefore, we generate two classes of WH solutions using this in energy-momentum trace-coupling gravity. For the specific choice of the Casimir EoS relating the energy-momentum tensor components [Kar and Sahdev: Phys. Rev. D 52, 2030 (1995)] and different choices of redshift functions, we determine the WH geometry completely. The obtained WH solutions violate the NECs, and all qualitative constraints demanded for physically realizable WHs are satisfied. This is demonstrated via graphical plots for a suitably chosen range of coupling parameter values. Furthermore, our study investigates the repulsive effect of gravity, revealing that its presence leads to a negative deflection angle for photons traveling along null geodesics. Notably, we observe a consistent pattern of negative values for the deflection angle across all values of r₀ in the three scenarios considered, thus indicating the clear manifestation of the repulsive gravity effect. All of this is possible without invoking the existence of dark energy.

DOI: 10.1088/1674-1137/ad73ad

Source: http://hepnp.ihep.ac.cn/article/doi/10.1088/1674-1137/ad73ad