Chao Zhang
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Previous Organizations / Institutes
The organizations / institutes from the scholar's other articles in the past ten years
Research Subjects
Research Interests
Chao Zhang has a total of 31 co-authors. Here are the top co-authors by number of shared publications:
- Yungui Gong
Ningbo University
31 shared publications - Chunyu Zhang
Yangzhou University
13 shared publications - Dicong Liang
Department of Mathematics and Physics School of Biomedical Engineering Southern Medical University 510515 Guangzhou China
10 shared publications - Qing Gao
Southwest University
10 shared publications - Bin Wang
Center for Gravitation and Cosmology College of Physical Science and Technology Yangzhou University 225009 Yangzhou China
9 shared publications - Ning Dai
Department of Mathematics and Physics, Suzhou Polytechnic University, Suzhou, Jiangsu 215000, China
7 shared publications
Latest Publications
- 24 November 2025
- Published by American Physical Society (APS) in Physical Review D
- Vol. 112 (10)
Generic effective sources for first-order in mass-ratio gravitational self-force calculations in Schwarzschild spacetime
- 24 November 2025
- Published by American Physical Society (APS) in Physical Review D
- Vol. 112 (10)
Generic effective sources for first-order in mass-ratio gravitational self-force calculations in Schwarzschild spacetime
- 20 May 2025
- Published by American Physical Society (APS) in Physical Review D
- Vol. 111 (10)
Detecting massive vector fields with extreme-mass-ratio inspirals
- 20 May 2025
- Published by American Physical Society (APS) in Physical Review D
- Vol. 111 (10)
Detecting massive vector fields with extreme-mass-ratio inspirals
- Open Access
- 4 April 2025
- Published by Springer Nature in The European Physical Journal C
- Vol. 85 (4) , 1-11
The constraint on modified black holes with extreme mass ratio inspirals
The low-energy effective action of String Theory introduces corrections to the dilaton-graviton sector, resulting in deformed black holes beyond general relativity. We analyze extreme mass-ratio inspiral systems (EMRIs), where a stellar-mass object spirals into a slowly rotating supermassive black hole including a distinct deviation parameter. This study examines the effects of this deformation on the rate of change of orbital energy and angular momentum, orbital evolution, and phase dynamics, incorporating leading-order post-Newtonian corrections. The String theory parameter $$\alpha $$ will accelerate the EMRI merger because of the extra energy and angular momentum fluxes carried away by corrections to the dilaton-graviton sector. With 1-year observations of EMRIs, we employ the Fisher information matrix method to evaluate the potential for detecting deviations from general relativity through space-based gravitational wave detectors that utilize time-delay interferometry to suppress laser noise. The constraint on modified black holes, $$\varDelta \alpha \preceq 10^{-5}$$ , is almost the same with and without the time-delay interferometry combination. This analysis enhances our understanding and underscores the crucial role of observations in advancing gravitational phenomena within String Theory.- 4 April 2025
- Published by Springer Nature in The European Physical Journal C
- Vol. 85 (4) , 1-11
Open AccessThe constraint on modified black holes with extreme mass ratio inspirals
The low-energy effective action of String Theory introduces corrections to the dilaton-graviton sector, resulting in deformed black holes beyond general relativity. We analyze extreme mass-ratio inspiral systems (EMRIs), where a stellar-mass object spirals into a slowly rotating supermassive black hole including a distinct deviation parameter. This study examines the effects of this deformation on the rate of change of orbital energy and angular momentum, orbital evolution, and phase dynamics, incorporating leading-order post-Newtonian corrections. The String theory parameter $$\alpha $$ will accelerate the EMRI merger because of the extra energy and angular momentum fluxes carried away by corrections to the dilaton-graviton sector. With 1-year observations of EMRIs, we employ the Fisher information matrix method to evaluate the potential for detecting deviations from general relativity through space-based gravitational wave detectors that utilize time-delay interferometry to suppress laser noise. The constraint on modified black holes, $$\varDelta \alpha \preceq 10^{-5}$$ , is almost the same with and without the time-delay interferometry combination. This analysis enhances our understanding and underscores the crucial role of observations in advancing gravitational phenomena within String Theory. - 20 November 2024
- Published by American Physical Society (APS) in Physical Review D
- Vol. 110 (10)
Probing new fundamental fields with extreme mass ratio inspirals
- 20 November 2024
- Published by American Physical Society (APS) in Physical Review D
- Vol. 110 (10)
Probing new fundamental fields with extreme mass ratio inspirals
- Open Access
The constraint on modified black holes with extreme mass ratio inspirals
The low-energy effective action of String Theory introduces corrections to the dilaton-graviton sector, resulting in deformed black holes beyond general relativity. We analyze extreme mass-ratio inspiral systems (EMRIs), where a stellar-mass object spirals into a slowly rotating supermassive black hole including a distinct deviation parameter. This study examines the effects of this deformation on gravitational wave fluxes, orbital evolution, and phase dynamics, incorporating leading-order post-Newtonian corrections. With one-year observations of EMRIs, we employ the Fisher information matrix method to evaluate the potential for detecting deviations from general relativity through space-based gravitational wave detectors that utilize time-delay interferometry to suppress laser noise. The constraint on modified black holes, $Δα\preceq 10^{-5}$, is almost the same with and without the time-delay interferometry combination. This analysis enhances our understanding and underscores the crucial role of observations in advancing gravitational phenomena within String Theory.Open AccessThe constraint on modified black holes with extreme mass ratio inspirals
The low-energy effective action of String Theory introduces corrections to the dilaton-graviton sector, resulting in deformed black holes beyond general relativity. We analyze extreme mass-ratio inspiral systems (EMRIs), where a stellar-mass object spirals into a slowly rotating supermassive black hole including a distinct deviation parameter. This study examines the effects of this deformation on gravitational wave fluxes, orbital evolution, and phase dynamics, incorporating leading-order post-Newtonian corrections. With one-year observations of EMRIs, we employ the Fisher information matrix method to evaluate the potential for detecting deviations from general relativity through space-based gravitational wave detectors that utilize time-delay interferometry to suppress laser noise. The constraint on modified black holes, $Δα\preceq 10^{-5}$, is almost the same with and without the time-delay interferometry combination. This analysis enhances our understanding and underscores the crucial role of observations in advancing gravitational phenomena within String Theory. - 1 April 2024
- Published by IOP Publishing in Journal of Cosmology and Astroparticle Physics
- Vol. 2024 (04)
Detecting dark matter halos with extreme mass-ratio inspirals
Extreme mass ratio inspirals (EMRIs), where a small compact object inspirals into a supermassive black hole, are excellent sources for the space-based laser interferometer gravitational wave (GW) detectors. The presence of the dark matter (DM) halo surrounding the supermassive black hole will influence the orbital evolution and emitted gravitational waveform of the binary. By direct observation of GW signals, we assess the detector's capability to detect whether an EMRI is immersed in a DM halo and to measure its characteristic spatial scale a 0 and mass M halo. Apart from the GW emission, the dynamical friction and accretion caused by the DM halo can also affect the dynamics of an EMRI, leaving detectable signatures in the emitted gravitational signal. We perform a Fisher-matrix error analysis to estimate the errors of parameters a 0 and M halo, as well as their correlation. The results show that the highly correlated parameters a 0 and M halo deteriorate the detector's ability to measure DM halo even though the dephasing and mismatch between signals with and without DM indicate much difference. The effects of the dynamical friction and accretion can break possible degeneracy between parameters a 0 and M halo, thus greatly decreasing the uncertainty by about one order of magnitude.
- 1 April 2024
- Published by IOP Publishing in Journal of Cosmology and Astroparticle Physics
- Vol. 2024 (04)
Detecting dark matter halos with extreme mass-ratio inspirals
Extreme mass ratio inspirals (EMRIs), where a small compact object inspirals into a supermassive black hole, are excellent sources for the space-based laser interferometer gravitational wave (GW) detectors. The presence of the dark matter (DM) halo surrounding the supermassive black hole will influence the orbital evolution and emitted gravitational waveform of the binary. By direct observation of GW signals, we assess the detector's capability to detect whether an EMRI is immersed in a DM halo and to measure its characteristic spatial scale a 0 and mass M halo. Apart from the GW emission, the dynamical friction and accretion caused by the DM halo can also affect the dynamics of an EMRI, leaving detectable signatures in the emitted gravitational signal. We perform a Fisher-matrix error analysis to estimate the errors of parameters a 0 and M halo, as well as their correlation. The results show that the highly correlated parameters a 0 and M halo deteriorate the detector's ability to measure DM halo even though the dephasing and mismatch between signals with and without DM indicate much difference. The effects of the dynamical friction and accretion can break possible degeneracy between parameters a 0 and M halo, thus greatly decreasing the uncertainty by about one order of magnitude.
- Open Access
Rotating galactic black holes
The galactic black hole is a supermassive black hole located at the center of a galaxy surrounded by a dark matter halo. For the first time, we establish a generic, fully-relativistic formalism to calculate solutions of Einstein's gravity minimally coupled to an anisotropic fluid modeled by the Einstein cluster in axisymmetric, non-vacuum spacetimes, which are extensions of spherically-symmetric cases. These asymptotically flat spacetimes with regular horizons can describe the geometry of galaxies harboring supermassive black holes and are useful to constrain the environment surrounding astrophysical black holes. Our findings provide a solid groundwork for future studies on the shadows, quasi-normal modes, and other phenomena associated with rotating galactic black holes.
Open AccessRotating galactic black holes
The galactic black hole is a supermassive black hole located at the center of a galaxy surrounded by a dark matter halo. For the first time, we establish a generic, fully-relativistic formalism to calculate solutions of Einstein's gravity minimally coupled to an anisotropic fluid modeled by the Einstein cluster in axisymmetric, non-vacuum spacetimes, which are extensions of spherically-symmetric cases. These asymptotically flat spacetimes with regular horizons can describe the geometry of galaxies harboring supermassive black holes and are useful to constrain the environment surrounding astrophysical black holes. Our findings provide a solid groundwork for future studies on the shadows, quasi-normal modes, and other phenomena associated with rotating galactic black holes.
- Open Access
Detecting dark matter with extreme mass-ratio inspirals
Extreme mass ratio inspirals (EMRIs), where a small compact object inspiralls onto a supermassive black hole, are excellent sources for the space-based laser interferometer gravitational wave (GW) detectors. The presence of dark matter surrounding the supermassive black hole will influence the binary orbital evolution and emitted gravitational waveform. By direct observation of GW signals, we assess the detector's capability to detect whether an EMRI is immersed in a dark matter halo and to measure its characteristic spatial scale $a_0$ and mass $M_{\rm halo}$. Apart from the GW emission, the dynamical friction and accretion caused by the dark matter halo can also affect the dynamics of an EMRI, leaving detectable signatures in the emitted gravitational signal. We perform a Fisher-matrix error analysis to estimate the errors of parameters $a_0$ and $M_{\rm halo}$, as well as their correlation. The results show that the highly correlated parameters $a_0$ and $M_{\rm halo}$ deteriorate the detector's ability to measure dark matter even though the dephasing and mismatch between signals with and without dark matter indicate much difference. The effects of the dynamical friction and accretion can break possible degeneracies between parameters $a_0$ and $M_{\rm halo}$, thus greatly decreasing the uncertainty by about one order of magnitude.Open AccessDetecting dark matter with extreme mass-ratio inspirals
Extreme mass ratio inspirals (EMRIs), where a small compact object inspiralls onto a supermassive black hole, are excellent sources for the space-based laser interferometer gravitational wave (GW) detectors. The presence of dark matter surrounding the supermassive black hole will influence the binary orbital evolution and emitted gravitational waveform. By direct observation of GW signals, we assess the detector's capability to detect whether an EMRI is immersed in a dark matter halo and to measure its characteristic spatial scale $a_0$ and mass $M_{\rm halo}$. Apart from the GW emission, the dynamical friction and accretion caused by the dark matter halo can also affect the dynamics of an EMRI, leaving detectable signatures in the emitted gravitational signal. We perform a Fisher-matrix error analysis to estimate the errors of parameters $a_0$ and $M_{\rm halo}$, as well as their correlation. The results show that the highly correlated parameters $a_0$ and $M_{\rm halo}$ deteriorate the detector's ability to measure dark matter even though the dephasing and mismatch between signals with and without dark matter indicate much difference. The effects of the dynamical friction and accretion can break possible degeneracies between parameters $a_0$ and $M_{\rm halo}$, thus greatly decreasing the uncertainty by about one order of magnitude. - 30 November 2023
- Published by American Physical Society (APS) in Physical Review D
- Vol. 108 (10) , 104069
Detecting new fundamental fields with pulsar timing arrays
Strong evidence of the existence of the stochastic gravitational wave background (SGWB) has been reported recently by the North American Nanohertz Observatory for Gravitational Waves, the Parkes Pulsar Timing Array, the European Pulsar Timing Array, and the Chinese Pulsar Timing Array Collaborations. The Bayesian posteriors of the SGWB amplitude and spectrum are compatible with astrophysical predictions for the SGWB from a population of supermassive black hole binaries (SMBHBs). We discuss the modifications arising from the extra scalar or vector radiation to the characteristic dimensionless strain of gravitational waves from SMBHBs and explore the possibility of detecting charges carried by supermassive black holes in modified gravity. The Bayesian posteriors on the tensor amplitude and the spectral exponent of SGWB are and , and a rough upper limit is obtained for the SGWB scalar or vector amplitude. The Bayesian factor between the models with and without charge is only 0.6, so the current PTA data do not favor charged SMBHBs over neutral SMBHBs.- 30 November 2023
- Published by American Physical Society (APS) in Physical Review D
- Vol. 108 (10) , 104069
Detecting new fundamental fields with pulsar timing arrays
Strong evidence of the existence of the stochastic gravitational wave background (SGWB) has been reported recently by the North American Nanohertz Observatory for Gravitational Waves, the Parkes Pulsar Timing Array, the European Pulsar Timing Array, and the Chinese Pulsar Timing Array Collaborations. The Bayesian posteriors of the SGWB amplitude and spectrum are compatible with astrophysical predictions for the SGWB from a population of supermassive black hole binaries (SMBHBs). We discuss the modifications arising from the extra scalar or vector radiation to the characteristic dimensionless strain of gravitational waves from SMBHBs and explore the possibility of detecting charges carried by supermassive black holes in modified gravity. The Bayesian posteriors on the tensor amplitude and the spectral exponent of SGWB are and , and a rough upper limit is obtained for the SGWB scalar or vector amplitude. The Bayesian factor between the models with and without charge is only 0.6, so the current PTA data do not favor charged SMBHBs over neutral SMBHBs.