论文标题
大约在高阶标量理论中的隐形黑洞
Approximately stealth black hole in higher-order scalar-tensor theories
论文作者
论文摘要
我们研究了具有scordatura项的通用二次高阶标量理论，该术语有望提供具有及时标量字段曲线的隐形解决方案的一致扰动描述。在DHOST子类中，已知恰好的隐形解决方案会产生无限强烈耦合的扰动，因此无法信任。除了具有Scordatura术语（例如Ghost Concensation和U-Dhost）的DOLOST理论之外，我们表明无法将隐身配置实现为确切的解决方案，但是这些理论却承认了近似隐形解决方案，其中偏离隐形配置的偏差由衍生性扩张的质量规模$ M $ M $控制。大约隐形溶液是时间依赖性的，可以将其解释为由于标量场的积聚而导致的黑洞质量生长。 From observed astrophysical black holes, we put an upper bound on $M$ as $\hat{c}_{\rm D1}^{1/2} M\lesssim 2\times 10^{11}$ GeV, where $\hat{c}_{\rm D1}$ is a dimensionless parameter of order unity that characterizes the scordatura term.就$ m $而言，就足以低于上限，积聚很慢，并且可以将大约隐形解决方案视为在天体物理尺度上的隐身，而出于所有实际目的，而扰动一直较弱地耦合到截止$ m $，并且显然的幽灵显然是幽灵，而幽灵却比$ m $ a $ a $ heaver较重。
We investigate a generic quadratic higher-order scalar-tensor theory with a scordatura term, which is expected to provide a consistent perturbative description of stealth solutions with a timelike scalar field profile. In the DHOST subclass, exactly stealth solutions are known to yield perturbations infinitely strongly coupled and thus cannot be trusted. Beyond DHOST theories with the scordatura term, such as in ghost condensation and U-DHOST, we show that stealth configurations cannot be realized as exact solutions but those theories instead admit approximately stealth solutions where the deviation from the exactly stealth configuration is controlled by the mass scale $M$ of derivative expansion. The approximately stealth solution is time-dependent, which can be interpreted as the black hole mass growth due to the accretion of the scalar field. From observed astrophysical black holes, we put an upper bound on $M$ as $\hat{c}_{\rm D1}^{1/2} M\lesssim 2\times 10^{11}$ GeV, where $\hat{c}_{\rm D1}$ is a dimensionless parameter of order unity that characterizes the scordatura term. As far as $M$ is sufficiently below the upper bound, the accretion is slow and the approximately stealth solutions can be considered as stealth at astrophysical scales for all practical purposes while perturbations are weakly coupled all the way up to the cutoff $M$ and the apparent ghost is as heavy as or heavier than $M$.
