arXiv subjects

Xulong Yuan

Publications and source records attributed to Xulong Yuan.

4 recordsLinked to original sources

arXiv2026

Distinguishability of magnetic massive black holes from environmental mimics with inspiral gravitational waves

In this work, we investigate the ppE waveform imprints induced by the external magnetic fields of Bertotti-Robinson and Bonnor-Melvin black holes, with the aim of distinguishing such magnetic effects from environmental influences. We first compute the ppE frequency-domain waveform for a small black hole inspiraling into a massive KBR black hole, which corresponds to a Kerr black hole embedded in an external magnetic field. We find that the leading-order correction arising from the magnetic field is at the $-2$ PN order relative to the quadrupole term, while the next-leading-order correction is at $-1.5$ PN, originating from the spin of the black hole. We further examine the effects of a spinning KBM black hole, whose leading-order magnetic correction is at $-3$ PN, whereas its spin-induced correction is also at $-1.5$ PN. The leading-order ppE corrections for both KBR and KBM black holes do not appear degenerate with any modified theory of gravity effects; nonetheless, we demonstrate that they resemble the gravitational pull contributions from additional matter with power-law distributions of index $γ=1$ and 0, respectively. To break the degeneracy with a single event, we adopt the statistic F in former research to discriminate between these two classes of beyond-vacuum GR effects using multiple gravitational wave events. We show even with multiple event statistic, it is not always efficient to distinguish real magnetic field effect from corresponding gravitational pull effect, especially for Bertotti-Robinson magnetic effect. For Bonnor-Melvin black hole, there is a transition value of $ρ_0$ estimated around $10^{-4}\text{kg}/\text{m}^3$ and corresponding $B\sim 10^{4}\text{T}$ above which real magnetic effect can be efficiently distinguished from gravitational pull and below the transition value it cannot.

gr-qc↗

arXiv2025

Distinguish the environmental effects and modified theory of gravity with multiple massive black-hole binaries

In the typical data analysis and waveform modeling of the gravitational waves (GWs) signals for binary black holes (BBHs), it is assumed to be isolate sources in the vacuum within the theory of general relativity (GR). However, various kinds of matter may exist around the source or on the path to the detector, and there also exist many different kinds of modified theories of gravity. The effects of these modifications can be characterized within the parametrized post-Einstein (ppE) framework, and the corresponding phase corrections on the waveform at leading post-Newtonian (PN) order are also expressed by the additional parameters for these effects. In this work, we consider the varying-G theory and the dynamical friction of the dark matter spike as an example. Both of these two effects will modify the waveform at -4PN order, if we choose the suitable power law index for the spike. We choose to use a statistic to characterize the dispersion between the posterior of $\dot G$ for different events. For different astronomical models, we find that this statistic can distinguish these two models very effectively. This result indicates that we could use this statistic to distinguish other degenerate effects with the detection of multiple sources.

gr-qc↗

arXiv2025

Statistic threshold of distinguishing the environmental effects and modified theory of gravity with multiple massive black-hole binaries

In future space-borne \ac{GW} observations, matter arround the sources might influence the evolution and \ac{GW} signals from \ac{BBH} inspirals, which can be mistaken as deviations from \ac{GR}. Former research \cite{yuan2024} proposed a statistic $F$ that characterizes the dispersion of measured parameters to distinguish environmental effect(\ac{DF} from \ac{DM} spike) and theory of modified gravity effect(varying $G$). In this work we use the statistic to distinguish other couples of effects with \ac{GW} corrections at $-4$ PN order: \ac{DF} from \ac{DM} spike and the extra dimension theory, additionally try to determine the distinguishing threshold in more reasonable way to avoid arbitrariness, especially when the two effects to compare have more overlap in the $F$ distribution. Sources of different astronomical models are also considered, and two effects are still distinguishable but not much as in former work\cite{yuan2024}, so the threshold should be carefully selected. Following these procedures, we finally obtain the statistic thresholds of distinguishment between the three effects with \ac{GW} corrections at $-4$ PN order: \ac{DF} from \ac{DM} spike, the extra dimension theory, and varying $G$ theory. The method can be used to distinguish other effects among environmental effects and modified theories of gravity effects with the detections of \ac{GW} events.

gr-qc↗

arXiv2019

Collision of spinning particles near BTZ black holes

We study the collision property of spinning particles near a Bañados-Teitelboim-Zanelli (BTZ) black hole. Our results show that although the center-of-mass energy of two ingoing particles diverges if one of the particles possesses a critical angular momentum, however, particle with critical angular momentum can not exist outside of the horizon due to the violation of timelike constraint. Further detailed investigation indicates that only the particle with a subcritical angular momentum is allowed to exist near an extremal rotating BTZ black hole and the corresponding collision center-of-mass energy can be arbitrarily large in a critical angular momentum limit.

gr-qc↗