75 citations · 505 across the 34 of their papers we have counts for
35 papers
Optimal all-angle reconstruction of the Hellings-Downs curve
Jing-Hong Han, Zhi-Chao Zhao
Pulsar timing arrays (PTAs) detect nanohertz gravitational waves through spatial correlations between the timing residuals of different pulsars. For an isotropic, unpolarized stoch…
Probing Graviton Mass with MeerKAT PTA and SKA-PTA Forecasts
Zhi-Chao Zhao, Sai Wang
In this study, we derive constraints on the graviton mass using the 4.5-year data release from the MeerKAT Pulsar Timing Array (MPTA) and provide forecasts for the upcoming Square…
Solving Hamiltonian Constraint Equation with Physics-Informed Neural Networks
Yu-Chen Zhou, Hao Ma, Zhoujian Cao +6
Numerical relativity (NR), solving Einstein equation numerically, plays an important role in source modelling for gravitational wave astronomy. Traditional methods for NR including…
Constraints on the Sum of Neutrino Masses from ACT DR6 and DESI DR2 Considering Isocurvature Initial Conditions
Hongsheng Hou, Sai Wang, Zhi-Chao Zhao +1
We present a robust assessment of cosmological constraints on the sum of neutrino masses () when relaxing the standard assumption of purely adiabatic primordial initial c…
Forecasting graviton-mass constraints from the full covariance of PTA-astrometry ORF estimators
Jing-Hong Han, Zhi-Chao Zhao
We develop a full-covariance formalism for pulsar timing array(PTA) -- astrometry verlap reduction function (ORF) estimators and use it to forecast graviton-mass constraints from a…
Reassessing the SIGW Interpretation of PTA Signal: The Role of Third-Order Gravitational Waves and Implications for the PBH Overproduction
Zhi-Chao Zhao, Sai Wang, Qing-Hua Zhu +1
In light of recent interpretations attributing pulsar timing array (PTA) signal to second-order gravitational waves induced by linear cosmological curvature perturbations in the ea…
Gravitational lensing of gravitational waves: universal characteristics of strongly lensed memory waveforms
Ruanjing Zhang, Zhi-Chao Zhao, Shaoqi Hou +3
In this work, the strong lensing effect of the memory signal was considered. In the geometric optics limit, the lensed memory signal becomes oscillatory, while the unlensed is basi…
Isotropy, anisotropies and non-Gaussianity in the scalar-induced gravitational-wave background: diagrammatic approach for primordial non-Gaussianity up to arbitrary order
Jun-Peng Li, Sai Wang, Zhi-Chao Zhao +1
Produced nonlinearly by the enhanced linear cosmological curvature perturbations, the scalar-induced gravitational waves (SIGWs) can serve as a potentially powerful probe of primor…
Constraints on the lepton asymmetry from DESI DR2 BAO data
Zhi-Chao Zhao, Dong-Mei Xia, Sai Wang
It is important to explore the potential existence of lepton asymmetry in the neutrino sector. Conducting a joint analysis of DESI DR2 BAO data and \emph{Planck} 2018 CMB data, we…
Study of primordial non-Gaussianity and with the cross-correlations between the scalar-induced gravitational waves and the cosmic microwave background
Zhi-Chao Zhao, Sai Wang, Jun-Peng Li +1
The stochastic gravitational-wave background originating from cosmic sources contains vital information about the early universe. In this work, we comprehensively study the cross-c…
Measuring the anisotropies in astrophysical and cosmological gravitational-wave backgrounds with Taiji and LISA networks
Zhi-Chao Zhao, Sai Wang
We investigate the capabilities of space-based gravitational-wave detector networks, specifically Taiji and LISA, to measure the anisotropies in stochastic gravitational-wave backg…
Angular bispectrum and trispectrum of scalar-induced gravitational waves: all contributions from primordial non-Gaussianity and
Jun-Peng Li, Sai Wang, Zhi-Chao Zhao +1
Studying the primordial non-Gaussianity of inflationary perturbations is crucial for testing the inflation paradigm of the early universe. In this work, we conduct a comprehensive…
Complete analysis of the background and anisotropies of scalar-induced gravitational waves: primordial non-Gaussianity and considered
Jun-Peng Li, Sai Wang, Zhi-Chao Zhao +1
Investigation of primordial non-Gaussianity holds immense importance in testing the inflation paradigm and shedding light on the physics of the early Universe. In this study, we co…
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…
Unveiling the Graviton Mass Bounds through Analysis of 2023 Pulsar Timing Array Data Releases
Sai Wang, Zhi-Chao Zhao
Strong evidence for the Helling-Downs correlation curves have been reported by multiple pulsar timing array (PTA) collaborations in middle 2023. In this work, we investigate the gr…
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…
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…
Primordial Non-Gaussianity and Anisotropies in Scalar-Induced Gravitational Waves
Jun-Peng Li, Sai Wang, Zhi-Chao Zhao +1
Primordial non-Gaussianity encodes vital information of the physics of the early universe, particularly during the inflationary epoch. To explore the local-type primordial non-Gaus…
Bayesian Implications for the Primordial Black Holes from NANOGrav's Pulsar-Timing Data Using the Scalar-Induced Gravitational Waves
Zhi-Chao Zhao, Sai Wang
Assuming that the common-spectrum process in the NANOGrav 12.5-year dataset has an origin of scalar-induced gravitational waves, we study the enhancement of primordial curvature pe…
Gravitational wave memory produced by cosmic background radiation
Zhoujian Cao, Xiaokai He, Zhi-Chao Zhao
It is well known that energy fluxes will produce gravitational wave memory. The gravitational wave memory produced by background including cosmic microwave background (CMB), cosmic…
Multi-TeV photons from GRB 221009A: uncertainty of optical depth considered
Zhi-Chao Zhao, Yong Zhou, Sai Wang
It is reported that the Large High Altitude Air Shower Observatory (LHAASO) observed thousands of very-high-energy photons up to 18 TeV from GRB 221009A. We study the surviva…
Search for the birefringence of gravitational waves with the third observing run of Advanced LIGO-Virgo
Zhi-Chao Zhao, Zhoujian Cao, Sai Wang
Gravitational waves would attain birefringence during their propagation from distant sources to the Earth, when the CPT symmetry is broken. If it was sizeable enough, such birefrin…
Gravitational wave memory of the binary black hole events in GWTC-2
Zhi-Chao Zhao, Xiaolin Liu, Zhoujian Cao +1
Gravitational wave (GW) memory is an important prediction of general relativity. Existing works on the GW memory detection focus on the waveform analysis. It is hard for waveform a…
Stochastic gravitational wave background due to gravitational wave memory
Zhi-Chao Zhao, Zhoujian Cao
Gravitational wave memory is an important prediction of general relativity, which has not been detected yet. Amounts of memory events can form a stochastic gravitational wave memor…