46 citations · 127 across the 13 of their papers we have counts for
13 papers
Scalar-induced gravitational waves from a box-shaped curvature power spectrum
Zu-Cheng Chen, Lang Liu
We compute the stochastic background of gravitational waves (GWs) produced at second order in cosmological perturbation theory by a primordial curvature power spectrum that is flat…
GW231123 Mass Gap Event and the Primordial Black Hole Scenario
Chen Yuan, Zu-Cheng Chen, Lang Liu
We investigate the possibility that the recently reported GW231123 event, with component masses , and a local merger ra…
Polynomial Potential Inflation in the ACT Era: From CMB to Primordial Black Holes
Zhi-Zhang Peng, Zu-Cheng Chen, Lang Liu
The recent measurements from the Atacama Cosmology Telescope (ACT) favor a higher value of the scalar spectral index compared to the Planck data, challenging many well-establ…
On the Gauge Invariance of Secondary Gravitational Waves
Chen Yuan, Yizhou Lu, Zu-Cheng Chen +1
Second-order tensor perturbations induced by primordial fluctuations play a crucial role in probing small-scale physics, but gauge dependence of their energy density has remained a…
Gauge Dependence of Gravitational Waves Induced by Primordial Isocurvature Fluctuations
Chen Yuan, Zu-Cheng Chen, Lang Liu
Primordial isocurvature perturbations, which can arise from various sources in the early Universe, have the potential to leave observable imprints on the gravitational-wave backgro…
Search for a Gravitational-Wave Background from Sound Speed Resonance from Advanced LIGO and Advanced Virgo's First Three Observing Runs
You Wu, Zu-Cheng Chen, Lang Liu
We search for a stochastic gravitational-wave background (SGWB) originating from scalar-induced gravitational waves (SIGWs) with the sound speed resonance (SSR) effect using data f…
Constraints on Inflation with Null Energy Condition Violation from Advanced LIGO and Advanced Virgo's First Three Observing Runs
Zu-Cheng Chen, Lang Liu
The null energy condition (NEC) is a cornerstone of general relativity, and its violation could leave observable imprints in the cosmic gravitational wave spectrum. Theoretical mod…
Constraining the nonstandard propagating gravitational waves in the cosmological background with GWTC-3
Zu-Cheng Chen, Lang Liu
The detection of gravitational waves (GWs) has opened a new window to test the fundamental nature of gravity. We present constraints on the nonstandard propagation of GWs using the…
Detecting a Gravitational-Wave Background from Inflation with Null Energy Condition Violation: Prospects for Taiji
Zu-Cheng Chen, Lang Liu
The null energy condition (NEC) is a fundamental principle in general relativity, and its violation could leave discernible signatures in gravitational waves (GWs). A violation of…
Can we distinguish the adiabatic fluctuations and isocurvature fluctuations with pulsar timing arrays?
Zu-Cheng Chen, Lang Liu
Understanding the nature of primordial fluctuations is pivotal to unraveling the Universe's early evolution. While these fluctuations are observed to be nearly scale-invariant, qua…
Is PSR J05144002E in a PBH-NS binary?
Zu-Cheng Chen, Lang Liu
Recent pulsar timing observations using MeerKAT of the eccentric binary millisecond pulsar, PSR J05144002E, have unveiled a companion with a mass in the mass gap, ranging from $…
Probing the speed of scalar-induced gravitational waves with pulsar timing arrays
Zu-Cheng Chen, Jun Li, Lang Liu +1
Recently, several regional pulsar timing array collaborations, including CPTA, EPTA, PPTA, and NANOGrav, have individually reported compelling evidence for a stochastic signal at n…
Simultaneously probing the sound speed and equation of state of the early Universe with pulsar timing arrays
Lang Liu, You Wu, Zu-Cheng Chen
Recently, several major pulsar timing array (PTA) collaborations have assembled strong evidence for the existence of a gravitational-wave background at frequencies around the nanoh…