用于亚稳宇宙弦的LISA重建景观
LISA Reconstruction Landscape for Metastable Cosmic Strings
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中文总结 AI 辅助
本研究利用LISA通过贝叶斯分析重建亚稳宇宙弦的随机引力波背景，基于谱特征探测弦张力与亚稳尺度，明确了LISA探测弦网络寿命的能力范围。
中文摘要 AI 辅助
我们研究利用激光干涉空间天线（Laser Interferometer Space Antenna, LISA）对来自亚稳宇宙弦的随机引力波背景进行重建。在真空隧穿基准场景中，宇宙弦网络通过弦世界面上单极子对的零温成核发生衰变。该网络初始遵循宇宙弦标度行为，在与有效环断裂及网络坍缩相关的衰变时间后，环的产生受到抑制。这种有限的寿命会在引力波谱中留下红外尾，并向类稳定弦的高频平台过渡。我们使用包含仪器噪声和未分辨天体物理前景的合成LISA数据，在$(G\boldsymbol{\u03bc},\boldsymbol{\u03ba}_{\rm CS})$参数空间中开展贝叶斯分析。我们绘制了可探测性、不确定性、相关性及定位能力的图谱，以区分背景探测与参数重建。重建过程由LISA频段中依赖于寿命的谱特征主导。当LISA采样红外尾与平台的过渡阶段时，数据包含振幅和形状信息，能够恢复弦张力和亚稳尺度。后验分布可能仍存在相关性，反映出振幅与寿命的权衡关系，但仅占据较小的参数区域。相比之下，无特征的谱仅能约束有限的参数组合或受先验主导。高信噪比的类平台谱即使在过渡阶段不明显时，也能通过残余的寿命依赖关系保留对$\boldsymbol{\u03ba}_{\rm CS}$的部分敏感性。最后，我们通过对比灵活模板与简化tanh模板，评估了对银道面前景建模的敏感性。我们的结果明确了LISA能够从探测阶段进一步深入，探测 underlying 弦网络寿命的范围。
英文摘要
We study reconstruction of stochastic gravitational-wave backgrounds from metastable cosmic strings with the Laser Interferometer Space Antenna (LISA). In the vacuum-tunneling benchmark, the network decays via zero-temperature nucleation of monopole pairs on the string worldsheet. Initially following cosmic-string scaling, loop production is suppressed after a decay time linked to efficient loop breaking and network collapse. This finite lifetime imprints an infrared tail and a transition toward a stable-string-like high-frequency plateau. Using synthetic LISA data with instrumental noise and unresolved astrophysical foregrounds, we perform Bayesian analysis in the $(Gμ,κ_{\rm CS})$ parameter space. We map detectability, uncertainties, correlations, and localization to distinguish background detection from parameter reconstruction. Reconstruction is governed by lifetime-dependent spectral features in the LISA band. When LISA samples the transition between tail and plateau, data contain amplitude and shape information, enabling recovery of string tension and metastability scale. Posteriors may remain correlated, reflecting an amplitude--lifetime trade-off, yet occupy a small parameter region. By contrast, featureless spectra constrain only limited parameter combinations or become prior dominated. High-SNR plateau-like spectra can retain partial sensitivity to $κ_{\rm CS}$ through residual lifetime dependence even when the transition is not prominent. Finally, we assess sensitivity to Galactic foreground modeling by comparing a flexible template with a reduced tanh template. Our results show where LISA can move beyond detection to probe the lifetime of the underlying string network.
