标题： 可穿越的虫洞和光环 显示英文标题

标题： Traversable wormholes and light rings

摘要： 超紧凑天体（UCOs）是没有视界的紧凑天体，它们表现出光环（LRs）——圆形光子轨道。因此，它们可能是黑洞的模仿者。几年前，Cunha 等人建立了一个定理，指出在一般假设下，由平滑、准闵可夫斯基初始数据形成的 UCO 必须至少有一对 LRs，其中一个是稳定的。这些稳定的 LRs 被认为会触发时空中的非线性不稳定性，可能会削弱 UCO 复制黑洞现象学的能力。然而，这个 LR 定理并不适用于虫洞，因为虫洞代表的是拓扑非平凡的时空。我们通过证明以下定理来解决虫洞的情况：一个在 1+3 维中连接两个不同渐近区域的静态、轴对称、渐近平坦、可穿越的虫洞，对于每种旋转方向至少有一个标准 LR。因此，任何（这样的）虫洞都是 UCO。通过填补这一空白，我们的结果不仅拓宽了对 UCO 的认识范围，还突显了它们密切模仿黑洞现象学的潜力。 显示英文摘要

摘要： Ultracompact objects (UCOs) are horizonless compact objects that present light rings (LRs) - circular photon orbits. As a result, they could be black hole mimickers. Some years ago, Cunha et al. established a theorem stating that, under general assumptions, UCOs formed from smooth, quasi-Minkowski initial data, must have at least a pair of LRs, one of which must be stable. These stable LRs are supposed to trigger a non-linear instability in spacetime, potentially weakening UCOs' ability to replicate black hole phenomenology. However, this LR theorem does not extend to wormholes, which represent topologically nontrivial spacetimes. We address the wormhole case by proving the following theorem: a stationary, axisymmetric, asymptotically flat, traversable wormhole in 1+3 dimensions, connecting two different asymptotic regions, has at least one standard LR for each rotation sense. Thus, any (such) wormhole is an UCO. By filling this gap, our results not only broaden the horizon of knowledge on UCOs but also highlight their potential to closely mimic black hole phenomenology.