75 citations · 353 across the 17 of their papers we have counts for
17 papers
New constraints on primordial non-Gaussianity from missing two-loop contributions of scalar induced gravitational waves
Zhe Chang, Yu-Ting Kuang, Di Wu +2
We analyze the energy density spectrum of \acp{SIGW} using the NANOGrav 15-year data set, thereby constraining the primordial non-Gaussian parameter . For the firs…
Unraveling the early universe's equation of state and primordial black hole production with PTA, BBN, and CMB observations
Qing-Hua Zhu, Zhi-Chao Zhao, Sai Wang +1
Pulsar timing array (PTA) data releases showed strong evidence for a stochastic gravitational-wave background in the nanohertz band. When the signal is interpreted by a scenario of…
Constraints On Scalar-Induced Gravitational Waves Up To Third Order From Joint Analysis of BBN, CMB, And PTA Data
Sai Wang, Zhi-Chao Zhao, Qing-Hua Zhu
Recently, strong evidence for a gravitational wave background has been reported by collaborations of pulsar timing arrays (PTA). In the framework of scalar-induced gravitational wa…
Primordial black holes and scalar induced density perturbations: the effects of probability density functions
Jing-Zhi Zhou, Yu-Ting Kuang, Zhe Chang +2
We investigate the second order energy density perturbation induced by small-scale Gaussian and local-type non-Gaussian primordial curvature perturbations. The relative a…
Implications of Pulsar Timing Array Data for Scalar-Induced Gravitational Waves and Primordial Black Holes: Primordial Non-Gaussianity Considered
Sai Wang, Zhi-Chao Zhao, Jun-Peng Li +1
Multiple pulsar-timing-array collaborations have reported strong evidence for the existence of a gravitational-wave background. We study physical implications of this signal for co…
Photon ring autocorrelations from gravitational fluctuations around a black hole
Qing-Hua Zhu
The images of supermassive black holes in M87 and our galaxy captured by the Event Horizon Telescope (EHT) might open up a new way for exploring black hole physics at the horizon s…
Overlap reduction function for gravitational wave detectors in an expanding Universe
Qing-Hua Zhu
Since it was confirmed two decades ago that the expansion of the Universe is accelerating, it would be of theoretical interests to figure out what is the influence from cosmologica…
The Shadow of Supertranslated Schwarzschild Black Hole
Qing-Hua Zhu, Yu-Xuan Han, Qing-Guo Huang
The supertranslated black hole proposed by Hawking, Perry, and Strominger might provide a resolution to the information paradox, which is usually defined by a complicated space-tim…
The Third Order Scalar Induced Gravitational Waves
Jing-Zhi Zhou, Xukun Zhang, Qing-Hua Zhu +1
Since the gravitational waves were detected by LIGO and Virgo, it has been promising that lots of information about the primordial Universe could be learned by further observations…
The observer-dependent shadow of the Kerr black hole
Zhe Chang, Qing-Hua Zhu
Motivated by inclination of the Earth's orbit that is not located at galactic plane for observing the shadow of Sgr A*, we consider the black hole shadow for arbitrary inclinations…
Spatial variation of the fine-structure constant and Hubble's law in anisotropic coordinate of Friedmann-Lemaitre-Robertson-Walker space-time
Zhe Chang, Qing-Hua Zhu
Recent updated results of quasar spectra suggested a 3.9 significance of spatial variation of the fine-structure constant. Theoretically, it is important to examine whether the…
On the Gauge Invariance of Scalar Induced Gravitational Waves: Gauge Fixings Considered
Zhe Chang, Sai Wang, Qing-Hua Zhu
The energy density spectrum is an observable of gravitational waves. Divergence has appeared in the energy density spectra of the scalar induced gravitational waves for different g…
Gauge Invariant Second Order Gravitational Waves
Zhe Chang, Sai Wang, Qing-Hua Zhu
We investigate the gauge invariance of the second order gravitational waves induced by the first order scalar perturbations by following the Lie derivative method. It is shown expl…
Note on gauge invariance of second order cosmological perturbations
Zhe Chang, Sai Wang, Qing-Hua Zhu
We study the gauge invariant cosmological perturbations up to second order. We show that there are infinite families of gauge invariant variables at both of the first and second or…
Does the shape of the shadow of a black hole depend on motional status of an observer?
Zhe Chang, Qing-Hua Zhu
In a recent work on rotating black hole shadows [Phys. Rev. D{\bf 101}, 084029 (2020)], we proposed a new approach for calculating size and shape of the shadows in terms of astrome…
A revisit of rotating black hole shadow with astrometric observables
Zhe Chang, Qing-Hua Zhu
The first image of black hole in M87 galaxy taken by Event Horizon Telescope shows that directed observation of supermassive black holes would be a promising way to test general re…
Reference frame dependence of the local measurement of the Hubble constant
Zhe Chang, Qing-Hua Zhu
Observations recently suggest discrepancy between Hubble constant measured locally and that inferred from cosmic microwave background in standard cosmology. Either standard…