Black holes in binaries with other compact objects can provide natural venues for indirect detection of axions or other ultralight fields. The superradiant instability associated with a rapidly spinning black hole leads to the creation of an axion cloud which carries energy and angular momentum from the black hole. This cloud will then decay via gravitational wave emission. We show that the energy lost as a result of this process tends toward an outspiraling of the binary orbit. A given binary system is sensitive to a narrow range of axion masses, determined by the mass of the black hole. Pulsar-black hole binaries, once detected in the electromagnetic band, will allow high-precision measurements of black hole mass loss via timing measurements of the companion pulsar. This avenue of investigation is particularly promising in light of the recent preliminary announcements of two candidate black hole-neutron star mergers by LIGO/VIRGO (#S190814bv and #S190426c). We demonstrate that for such a binary system with a typical millisecond pulsar and a 3-solar-mass black hole, axions with masses between $2.7 \times 10^{-12}$ eV and $3.2 \times 10^{-12}$ eV are detectable. Recent gravitational wave observations by LIGO/VIRGO of binary black hole mergers imply that, for these binaries, gravitational radiation from the rotating quadrupole moment is a dominant effect, causing an inspiraling orbit. With some reasonable assumptions about the period of the binary when it formed and the spins of the black holes, these observations rule out possible axion masses between $3 \times 10^{-13}$ eV and $6 \times 10^{-13}$ eV. Future binary black hole observations, for example by LISA, are expected to provide more robust bounds. In some circumstances, neutron stars may also undergo superradiant instabilities, and binary pulsars could be used to exclude axions with certain masses and matter couplings.

中文翻译：

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通过压缩对象二进制文件访问 axion

带有其他致密物体的双星中的黑洞可以为轴子或其他超轻场的间接探测提供自然场所。与快速旋转的黑洞相关的超辐射不稳定性导致轴子云的产生，轴子云从黑洞携带能量和角动量。然后，该云将通过引力波发射衰变。我们表明，由于这个过程而损失的能量倾向于超出双星轨道。给定的双星系统对由黑洞质量决定的轴子质量范围很窄很敏感。脉冲星-黑洞双星一旦在电磁带中被探测到，将允许通过对伴脉冲星的计时测量来高精度测量黑洞质量损失。鉴于 LIGO/VIRGO（#S190814bv 和 #S190426c）最近初步宣布了两个候选黑洞-中子星合并，这种调查途径特别有希望。我们证明，对于具有典型毫秒脉冲星和 3 倍太阳质量黑洞的双星系统，轴子质量在 $2.7 \times 10^{-12}$ eV 和 $3.2 \times 10^{-12}$ eV 之间是可检测的。最近 LIGO/VIRGO 对双黑洞合并的引力波观测表明，对于这些双星，来自旋转四极矩的引力辐射是主要效应，导致了一个令人振奋的轨道。对双星形成时的周期和黑洞的自旋做了一些合理的假设，这些观察排除了 $3 \times 10^{-13}$ eV 和 $6 \times 10^{-13} 之间可能的轴子质量$ eV。未来的双黑洞观测，例如 LISA，预计将提供更强大的界限。在某些情况下，中子星也可能经历超辐射不稳定性，双脉冲星可用于排除具有特定质量和物质耦合的轴子。