I’m a postdoctoral researcher in the Computational Relativistic Astrophysics division led by Masaru Shibata at the Albert Einstein Institute, Potsdam. Previously, I was a Ph.D. student in Lijing Shao’s KIAAGravity Group at Peking University. My research combines analytical modelling, relativistic perturbation theory and numerical relativity to probe dense matter inside neutron stars and gravity in the strong-field regime. See my research, publications, and CV for more.
Recent work
Relativistic tidal response and mode excitation in neutron-star binaries
Y. Gao and J. Steinhoff — arXiv:2611.14243 (2026)
We calculate the relativistic dynamical tidal response of neutron stars with composition stratification, elastic crusts and possible first-order phase transitions. Matching stellar perturbations to effective field theory through analytical Mano–Suzuki–Takasugi exterior solutions gives mode frequencies and tidal couplings. We incorporate these modes into effective-one-body evolution to follow their excitation, gravitational-wave emission and crustal strain. In a representative hadronic–hybrid binary, the low-frequency modes produce a small gravitational-wave phase shift, yet gravity and shear modes can still drive parts of the crust beyond its breaking strain.
Quasi-normal modes and instabilities of rotating relativistic stars
Y. Gao and M. Shibata — arXiv:2611.03986 (2026)
We directly calculate complex mode frequencies of rapidly rotating stars in full general relativity. Starting from the second-order Einstein–fluid action, we solve the coupled fluid–spacetime eigenvalue problem with outgoing-wave boundary conditions. The spectrum includes f, r, other inertial and strongly damped w modes, together with their damping or growth rates. The framework resolves secular and dynamical instabilities, mode interactions and the onset of quasiradial collapse.
Subsolar-mass binary mergers of strange stars and neutron stars: gravitational waves and ejecta
Y. Gao, M.-Z. Han, K. Kiuchi, M. Shibata, E. Zhou and K. Hotokezaka — arXiv:2607.07668 (2026)
I constructed binary initial data and carried out the first numerical-relativity simulations of subsolar-mass strange-star mergers. Comparing them with neutron-star binaries, we find that the ratio of the postmerger peak frequency to the inspiral cutoff frequency separates the two classes in the simulated models. Strange-star mergers can eject about 0.01 solar masses of decompressed quark matter, providing a possible source of an electromagnetic counterpart to subsolar-mass events.
Convective stability of massive neutron stars formed in binary mergers
Y. Gao, K. Hayashi, K. Kiuchi, A. T.-L. Lam, H.-J. Kuan, M. Shibata — Phys. Rev. D 113, 023011 (2026)
We run fully general-relativistic hydrodynamics simulations of binary neutron-star mergers out to 100 ms post-merger and derive — then apply for the first time — convective-stability criteria for hot, differentially rotating relativistic stars that include both buoyancy and rotation. The remnant massive neutron stars show no large-scale convective instability: entropy and angular momentum both increase outward, and rotation stabilizes regions that the Schwarzschild criterion would call unstable. Mode analysis reveals no observable inertial modes after the quadrupolar f-modes damp, while the persistent m=1 one-armed mode correlates strongly with violations of linear-momentum conservation — suggesting it may be numerical rather than physical.
Nonradial oscillations of stratified neutron stars with solid crusts
Y. Gao, H.-J. Kuan, C.-J. Xia, H. O. Silva, M. Shibata — Phys. Rev. D 112, 123006 (2025)
We model the dynamical tide of an inspiraling neutron star as a set of driven harmonic oscillators whose natural frequencies are the quasinormal modes of a fully relativistic stellar model with a solid crust and compositional stratification. Stratification erases the canonical crust–core interface mode and replaces it with compositional gravity modes anchored in outer-core buoyancy; meanwhile, the f-mode and core g-mode can leak into the crust under a penetration criterion we derive. The headline result for multimessenger observations: both resonant g-mode forcing and nonresonant f- and crustal-shear-mode driving can overstress the crust before merger, potentially channeling energy into the magnetosphere and powering electromagnetic precursors.
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