The gravitational field of compact objects, such as primordial black holes, can create multiple images of background sources. For transients such as fast radio bursts (FRBs), these multiple images can be resolved in the time domain. Under certain circumstances, these images not only have similar burst morphologies but are also phase-coherent at the electric field level. With a novel dechannelization algorithm and a matched filtering technique, we search for repeated copies of the same electric field waveform in observations of FRBs detected by the FRB backend of the Canadian Hydrogen Mapping Intensity Experiment (CHIME). An interference fringe from a coherent gravitational lensing signal will appear in the time-lag domain as a statistically significant peak in the time-lag autocorrelation function. We calibrate our statistical significance using telescope data containing no FRB signal. Our dataset consists of $\sim 100$-ms long recordings of voltage data from 172 FRB events, dechannelized to 1.25-ns time resolution. This coherent search algorithm allows us to search for gravitational lensing signatures from compact objects in the mass range of ${10}^{-4}–{10}^4{\mathrm{M}}_{\odot }$. After ruling out an anomalous candidate due to diffractive scintillation, we find no significant detections of gravitational lensing in the 172 FRB events that have been analyzed. In a companion work [C. Leung and Z. Kader, Phys. Rev. D 106, 043017 (2022).], we interpret the constraints on dark matter from this search.

中文翻译：

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使用 CHIME/FRB 的快速射电爆发引力透镜干涉法对紧凑物体进行高分辨率搜索

致密物体（例如原始黑洞）的引力场可以创建多个背景源图像。对于诸如快速射电暴 (FRB) 等瞬态，这些多幅图像可以在时域中解析。在某些情况下，这些图像不仅具有相似的突发形态，而且在电场水平上也是相位相干的。通过新的去通道化算法和匹配滤波技术，我们在加拿大氢测绘强度实验 (CHIME) 的 FRB 后端检测到的 FRB 观测中搜索相同电场波形的重复副本。来自相干引力透镜信号的干涉条纹将出现在时滞域中，作为时滞自相关函数中具有统计意义的峰值。我们使用不含 FRB 信号的望远镜数据来校准我们的统计显着性。我们的数据集包括$～100$-ms 长记录来自 172 个 FRB 事件的电压数据，去通道化为 1.25-ns 时间分辨率。这种相干搜索算法允许我们从质量范围内的紧凑物体中搜索引力透镜特征。${10}^{-4}–{10}^4{\mathrm{米}}_{\odot }$. 在排除了由于衍射闪烁引起的异常候选后，我们发现在已分析的 172 个 FRB 事件中没有发现明显的引力透镜现象。在配套作品中 [C. Leung 和 Z. Kader，Phys。Rev. D 106 , 043017 (2022).]，我们从这次搜索中解释了对暗物质的约束。