activity
20232026
most citedSimultaneously probing the sound speed and equation of state of the early Universe with pulsar timing arrays

46 citations · 164 across the 15 of their papers we have counts for

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7 papers · 1 filter

gr-qc2026

Alternative LISA-TAIJI networks: polarization separation of the stochastic gravitational wave background

Gang Wang, Lang Liu

Stochastic gravitational-wave backgrounds (SGWBs) provide a unique opportunity to probe both unresolved astrophysical populations and fundamental physics in the early Universe. Fut…

gr-qc2026

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…

gr-qc2024★ 1 cited

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…

gr-qc2024★ 9 cited

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…

gr-qc2024★ 7 cited

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…

gr-qc2024★ 17 cited

GW230529_181500: A Potential Primordial Binary Black Hole Merger in the Mass Gap

Qing-Guo Huang, Chen Yuan, Zu-Cheng Chen +1

During the fourth observing run of the LIGO-Virgo-KAGRA detector network, the LIGO Livingston observatory detected a coalescing compact binary, GW230529_181500, with component mass…

gr-qc2024★ 39 cited

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…