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Peng-Cheng Li

Publications and source records attributed to Peng-Cheng Li.

At least 37 records · Page 2Linked to original sources

Detecting the tidal heating with the generic extreme-mass-ratio inspirals

The horizon of a classical black hole (BH), functioning as a one-way membrane, plays a vital role in the dynamic evolution of binary BHs, capable of absorbing fluxes entirely. Tidal heating, stemming from this phenomenon, exerts a notable influence on the production of gravitational waves(GWs). If at least one member of a binary is an exotic compact object (ECO) instead of a BH, the absorption of fluxes is expected to be incomplete and the tidal heating would be different. Thus, tidal heating can be utilized for model-independent investigations into the nature of compact object. In this paper, assuming that the extreme-mass-ratio inspiral (EMRI) contains a stellar-mass compact object orbiting around a massive ECO with a reflective surface, we compute the GWs from the generic EMRI orbits. Using the accurate and analytic flux formulas in the black hole spacetime, we adapted these formulas in the vicinity of the ECO surface by incorporating a reflectivity parameter. Under the adiabatic approximation, we can evolve the orbital parameters and compute the EMRI waveforms. The effect of tidal heating for the spinning and non-spinning objects can be used to constrain the reflectivity of the surface at the level of 10^-6 by computing the mismatch and fisher information matrix.

gr-qc↗

The rotating solutions beyond the spontaneous scalarization in Einstein-Maxwell-scalar theory

The Einstein-Maxwell-scalar (EMS) theory with a quartic coupling function features three branches of fundamental black hole (BH) solutions, labeled as cold, hot, and bald black holes. The static bald black holes (the Reissner-Nordström BH) exhibit an intriguing nonlinear instability beyond the spontaneous scalarization. We study the rotating scalarized black hole solutions in the EMS model with a quartic coupling function through the spectral method numerically. The domain of existence for the scalarized BHs is presented in the spin-charge region. We found that the rotating solutions for both the two scalarized branches possess similar thermodynamic behavior compared to the static case while varying the electric charge. The BH spin enlarges the thermodynamic differences between the cold and hot branches. The profile of the metric function and the scalar field for the scalarized BHs is depicted, which demonstrates that the scalar field concentrates more on the equatorial plane in contrast to the axisymmetric region as the spin increases.

gr-qc↗

Gravitational waves from extreme-mass-ratio inspirals in the semiclassical gravity spacetime

More recently, Fernandes \cite{Fernandes:2023vux} discovered analytic stationary and axially-symmetric black hole solutions within semiclassical gravity, driven by the trace anomaly. The study unveils some distinctive features of these solutions. In this paper, we compute the gravitational waves emitted from the \ac{EMRI} around these quantum-corrected rotating black holes using the kludge approximate method. Firstly, we derive the orbital energy, angular momentum and fundamental frequencies for orbits on the equatorial plane. We find that, for the gravitational radiation described by quadrupole formulas, the contribution from the trace anomaly only appears at higher-order terms in the energy flux when compared with the standard Kerr case. Therefore, we can compute the EMRI waveforms from the quantum-corrected rotating black hole using the Kerr fluxes. We assess the differences between the EMRI waveforms from rotating black holes with and without the trace anomaly by calculating the dephasing and mismatch. Our results demonstrate that space-borne gravitational wave detectors can distinguish the EMRI waveform from the quantum-corrected black holes with a fractional coupling constant of $\sim 10^{-3}$ within one year observation. Finally, we compute the constraint on the coupling constant using the Fisher information matrix method and find that the potential constraint on the coupling constant by LISA can be within the error $\sim 10^{-4}$ in suitable scenarios.

gr-qc↗

Progress and outlook on advanced fly scans based on Mamba

Development related to PandABox-based fly scans is an important part of the active work on Mamba, the software framework for beamline experiments at the High Energy Photon Source (HEPS); presented in this paper is the progress of our development, and some outlook for advanced fly scans based on knowledge learned during the process. By treating fly scans as a collaboration between a few loosely coupled subsystems - motors / mechanics, detectors / data processing, sequencer devices like PandABox - systematic analyses of issues in fly scans are conducted. Interesting products of these analyses include a general-purpose software-based fly-scan mechanism, a general way to design undulator-monochromator fly scans, a sketch of how to practically implement online tuning of fly-scan behaviours based on processing of the data acquired, and many more. Based on the results above, an architectural discussion on >=10kHz fly scans is given.

physics.ins-det↗

Gravitational waves from extreme mass ratio inspirals around a hairy Kerr black hole

Recently, Contreras et al. \cite{Contreras:2021yxe} introduced a new type of black hole, called hairy Kerr black hole (HKBH), which describes a Kerr BH surrounded by an axially symmetric fluid with conserved energy momentum tensor. In this paper, we compute the gravitational waves emitted from the extreme mass ratio inspirals around the HKBHs. We solve the Dudley-Finley equation, which describes the gravitational perturbations of the HKBH, and obtain the energy fluxes induced by a stellar-mass compact object moving on the equatorial, circular orbits. Using the adiabatic approximation, we evolved the radii of the circular orbits by taking into account the backreaction of gravitational radiation. Then we calculate the dephasing and mismatch of the EMRI waveforms from the HKBH and Kerr BH to assess the difference between them. The results demonstrate that the EMRI waveforms from the HKBH with deviation parameter larger than $0.001$ and hair charge smaller than $1.5M$ can be discerned by LISA.

gr-qc↗

PandA(Box) flies on Bluesky: maintainable and user-friendly fly scans with Mamba at HEPS

Purpose: Fly scans are indispensible in many experiments at the High Energy Photon Source (HEPS). PandABox, the main platform to implement fly scans at HEPS, needs to be integrated into Mamba, the experiment control system developed at HEPS based on Bluesky. Methods: In less than 600 lines of easily customisable and extensible backend code, provided are full control of PandABox's TCP server in native ophyd, automated configuration (also including wiring) of "PandA blocks" for constant-speed mapping experiments of various dimensions, as well as generation of scans deliberately fragmented to deal with hardware limits in numbers of exposure frames or sequencer table entries. Results: The upper-level control system for PandABox has been ported to Bluesky, enabling the combination of both components' flexibility in fly-scan applications. Based on this backend, a user-friendly Mamba frontend is developed for X-ray fluorescence (XRF) mapping experiments, which provides fully online visual feedback.

physics.ins-det↗

Probing the Tidal Deformability of the Central Object in an Extreme Mass Ratio Inspiral with Analytic Kludge Waveforms

We develop approximate ``analytic-kludge" waveforms to describe the inspiral of a stellar-mass compact object into a supermassive compact object in an extreme mass ratio inspiral (EMRI) scenario. The deformability of the supermassive compact object is characterized by a dimensionless quantity called the tidal Love number (TLN). Our analysis shows that, up to the leading order of the mass ratio, the conservative dynamics of the EMRI are not affected by tidal interaction, and the tidal effect is only present in the induced quadrupole moment. We calculate the energy and angular momentum fluxes and obtain leading order corrections to the orbital evolution equations. By comparing the waveforms with and without tidal interaction, we demonstrate that even a small TLN can produce significant differences in the waveforms, which can be detected by space-borne detector LISA. Finally, using the Fisher information matrix method, we perform parameter estimation for the TLN and find that the precision can reach the level of $10^{-4}$ in suitable scenarios.

gr-qc↗

Quasinormal modes of rotating accelerating black holes

This paper studies the quasinormal mode spectrum of the scalar perturbation on the background of the rotating accelerating black holes. The quasinormal frequency $ω$ and the separation constant $λ$ are calculated using two methods: the continued fractions method and the directly integration method. The spectrum is found to include three families of modes: the photon sphere modes, the acceleration modes, and the near extreme modes. We investigate the effects of back hole parameters such as spin and acceleration. Empirical formulas are presented for the numerical results, specifically for the acceleration modes in the small black hole limit or the near extreme modes in the extreme black hole limit. An interesting phenomenon known as eigenvalue repulsion is observed when the acceleration modes intersect with the near extreme modes at certain parameter values. The strong cosmic censorship conjecture for spinning C-metric is respected.

gr-qc↗

Analytic Kludge Waveforms for Extreme Mass Ratio Inspirals of Charged Object around Kerr-Newman Black Hole

We derive the approximate, ``analytic-kludge'' (AK) waveforms for the inspiral of a charged stellar-mass compact object (CO) into a charged massive Kerr-Newman (KN) black hole (BH). The modifications of the inspiral orbit due to the charges in this system can be attributed to three sources: the electric force between the CO and the MBH, the energy flow of the dipole electromagnetic radiation, and the deformation of the metric caused by the charge of the MBH. All these are encoded explicitly in the fundamental frequencies of the orbits, which are calculated analytically in the weak-field regime. By calculating the mismatch between the waveforms for charged and neutral EMRI systems with respect to space-borne detectors TianQin and LISA, we show that tiny charges in the system can produce distinct imprints on the waveforms. Finally, we perform parameter estimation for the charges using the Fisher information matrix method and find that the precision can reach the level of $10^{-5}$ in suitable scenarios. We also study the effects of charges on the parameter estimation of charge, where the effects from the charge of the MBH can be well explained by its effects on the cutoff of the inspiral.

gr-qc↗

Probing chromatic onsets of gravitational wave overtones

The ringdown data of both GW150914 and GW190521\_074359 (GW190521r) show evidence supporting the presence of overtone. Previous studies all adopt a fundamental assumption, which were motivated more by convenience than by first principles, that the first overtone and the fundamental mode share a same onset. In this work, for the first time we relax such assumption, and we aim to probe the possible chromatic onsets of these two components within the GW150914 and GW190521r ringdown data. For both events, we bound the onset lags to be $Δt_0\geq 5M_f$ at probabilities of $\geq 94.7\%$, where $M_f$ is the mass of the remnant black hole formed in the merger. This result moderately favours the non-simultaneous excitation between the fundamental mode and the first overtone in the ringdown.

gr-qc↗

On AdS Black Strings at Large $D$

In this paper we study the stability of an homogeneous black string in the presence of a negative cosmological constant with minimally coupled scalar fields by using the large $D$ effective theory. This method allows us to explore the dynamics of the black strings in the nonlinear regime. We find that up to the next-to-leading order of the $1/D$ expansion, the unique consistent solution of the equations of motion must be uniform. This means the recently found Gregory-Laflamme instability caused by fined-tuned non-generic perturbations would die out at late time in the evolution of the system.

hep-th↗

Quasinormal-modes of the Kerr-Newman black hole: GW150914 and fundamental physics implications

We develop an analytical ringdown waveform model, including both the fundamental and the overtone quasinormal modes, for charged black holes and show that it is precise enough to analyze current gravitational wave data. Applying this waveform model to GW150914, the charge to mass ratio of the remnant black hole ($λ_f$) has been constrained with the sole ringdown gravitational wave data for the first time and the $90\%$ upper limit is $λ_f\leq 0.38$. Correspondingly, the deviation parameter of the scalar-tensor vector gravity ($α_{\rm s}$) is limited to be $α_{\rm s}\leq 0.17$. Our approach can be directly applied to other binary black hole mergers with loud ringdown radiation.

gr-qc↗

Correspondence of eikonal quasinormal modes and unstable fundamental photon orbits for Kerr-Newman black hole

In this work, we study the relation of the eikonal quasinormal modes (EQNMs) and the unstable fundamental photon orbits (UFPOs) in the Kerr-Newman spacetime. We find that in the eikonal limit the gravitational and electromagnetic perturbations of the Kerr-Newman black hole are naturally decoupled, and a single one-dimensional Schrödinger-like equation encoding the QNM spectrum can be derived. We then show that the decoupled Teukolsky master equation and the Klein-Gordon equation for the massless scalar field in the Kerr-Newman spacetime are of the same form in the eikonal limit. As a direct consequence, taking into account of the boundary conditions for EQNMs we show an exact correspondence between EQNMs and UFPOs, that is, EQNM/UFPO correspondence. More precisely, similar to the Kerr case, the real part of EQNM's frequency is a linear combination of the precessional and (polar) orbital frequencies, while the imaginary part of the frequency is proportional to the Lyapunov exponent of the UFPO.

gr-qc↗

Constrains on the electric charges of the binary black holes with GWTC-1 events

Testing black hole's charged property is a fascinating topic in modified gravity and black hole astrophysics. In the first Gravitational-Wave Transient Catalog (GWTC-1), ten binary black hole merger events have been formally reported, and these gravitational wave signals have significantly enhanced our understanding of the black hole. In this paper, we try to constrain the amount of electric charge with the parameterized post-Einsteinian framework by treating the electric charge as a small perturbation in a Bayesian way. We find that the current limits in our work are consistent with the result of Fisher information matrix method in previous works. We also develop a waveform model considering a leading order charge effect for binary black hole inspiral.

gr-qc↗

Tight constraints on Einstein-dilation-Gauss-Bonnet gravity from GW190412 and GW190814

Gravitational-wave (GW) data can be used to test general relativity in the highly nonlinear and strong field regime. Modified gravity theories such as Einstein-dilation-Gauss-Bonnet and dynamical Chern-Simons can be tested with the additional GW signals detected in the first half of the third observing run of Advanced LIGO/Virgo. Specifically, we analyze gravitational-wave data of GW190412 and GW190814 to place constraints on the parameters of these two theories. Our results indicate that dynamical Chern-Simons gravity remains unconstrained. For Einstein-dilation-Gauss-Bonnet gravity, we find $\sqrt{α_{\rm EdGB}}\lesssim 0.40\,\rm km$ when considering GW190814 data, assuming it is a black hole binary. Such a constraint is improved by a factor of approximately $10$ in comparison to that set by the first Gravitational-Wave Transient Catalog events.

gr-qc↗

High spin expansion for null geodesics

We consider the high spin expansion for the null geodesics in the Kerr spacetime. We expand the null geodesic equation successively to higher orders in deviation from extremity. Via the method of matched asymptotic expansion, the radial integrals are obtained analytically. It turns out that the analytic expressions are very sensitive to the value of the shifted Carter constant $q$. We show that for a large $q$, the analytic expressions can be used to study observational electromagnetic signatures for astrophysical black holes like M87*. However, for a small $q$, the high spin expansion method can only be applied to (near-) extreme black holes.

gr-qc↗

QED Effect on Black Hole Shadow

In this work, taking the QED effect into account, we investigate the shadows of the static black hole with magnetic monopoles and neutral black holes in magnetic fields through the numerical backward ray-tracing method. For a static black holes with magnetic monopole, we obtain the relation between the shadow radius and the coupling constant. For neutral black holes in the uniform magnetic fields, we find that the shadow curves deviate very small from the ellipses for equatorial observer, and we read the linear relation between the eccentricity and the coupling constant. For $θ_o\neqπ/2$, we find that the shadow curves can be well approximated by ellipses in most cases, except the case that the magnetic field is very strong and the observer sits around the angle $θ_o=π/4$ or $3π/4$. Moreover we extend our investigation to a neutral static black hole surrounded with a current loop.

gr-qc↗

Novel shadows from the asymmetric thin-shell wormhole

For dark compact objects such as black holes or wormholes, the shadow size has long been thought to be determined by the unstable photon sphere (region). However, by considering the asymmetric thin-shell wormhole (ATSW) model, we find that the impact parameter of the null geodesics is discontinuous through the wormhole in general and hence we identify novel shadows whose sizes are dependent of the photon sphere in the other side of the spacetime. The novel shadows appear in three cases: (A2) The observer's spacetime contains a photon sphere and the mass parameter is smaller than that of the opposite side; (B1, B2) there' s no photon sphere no matter which mass parameter is bigger. In particular, comparing with the black hole, the wormhole shadow size is always smaller and their difference is significant in most cases, which provides a potential way to observe wormholes directly through Event Horizon Telescope with better detection capability in the future.

gr-qc↗