We study the perturbative stability of Euclidean axion-dilaton wormholes that asymptotically approach flat space, both with a massless and a massive dilaton, and focus on homogeneous perturbations. We find massless wormholes to always be perturbatively stable. The phenomenologically more relevant case of a massive dilaton presents us with a wide variety of wormhole solutions, depending on the dilaton coupling and mass, and on the axion charge. We find that the solutions with the smallest dilaton potential are perturbatively stable and dominant, even in cases where the wormhole solutions are not continuously connected to the massless case by decreasing the mass. For branches of solutions emanating from a bifurcation point, one side of the branch always contains a negative mode in its spectrum, rendering such solutions unstable. The existence of classes of perturbatively stable wormhole solutions with massive dilaton sharpens the puzzles associated with Euclidean wormholes.

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轴子膨胀虫洞的稳定性

我们研究渐进接近平坦空间的欧几里得轴子膨胀虫洞的摄动稳定性，无论是无质量还是大膨胀，并重点关注均匀摄动。我们发现无质量虫洞总是保持微扰稳定。在现象学上更相关的大质量膨胀子案例为我们提供了各种各样的虫洞解决方案，具体取决于膨胀子耦合和质量以及轴子电荷。我们发现，即使在虫洞解没有通过减少质量来连续连接到无质量情况的情况下，具有最小膨胀势的解也是扰动稳定和占主导地位的。对于从分叉点发出的解的分支，分支的一侧在其频谱中始终包含负模式，使得此类解不稳定。具有大量膨胀的扰动稳定虫洞解的存在，加剧了与欧几里德虫洞相关的谜题。