Institute of Theoretical Physics

Integral Hilbert spaces and the dynamics of loop quantum cosmos

Janek Kozicki, Tomasz Pawłowski

Polymer quantization program applied in Loop Quantum Gravity/Cosmology leads to nonseparable Hilbert spaces. Commonly, one sidesteps this problem by singling out and working with a…

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…

gr-qc2026★ 4 cited

Topology of black hole thermodynamics: A brief review

Shao-Wen Wei, Yu-Xiao Liu

Recent explorations of topological aspects in black hole thermodynamics have achieved unprecedented progress. By utilizing topological numbers, different black hole systems can be…

Uniqueness of stationary axisymmetric type D black holes with non-aligned electromagnetic field

Hryhorii Ovcharenko, Jiri Podolsky

We demonstrate the uniqueness of the spacetimes recently found by us in [H. Ovcharenko and J. Podolsky, Phys. Rev. D 112 (2025) 064076]. First, we prove that the conformal-to-Carte…

Data-Driven Acceleration of Eccentricity Reduction for Binary Black Hole Simulations

Vittoria Tommasini, Nils L. Vu, Mark A. Scheel +1

Reducing orbital eccentricity in numerical relativity simulations of binary black holes is essential for producing astrophysically relevant gravitational wave models, as many of th…

Unifying topological, geometric, and complex classifications of black hole thermodynamics

Shi-Hao Zhang, Shao-Wen Wei, Jing-Fei Zhang +1

Black hole thermodynamics has recently witnessed three distinct classification schemes: based on local geometric properties of the temperature function, global topological invarian…

Interior geometry of black holes as a probe of first-order phase transition

Zi-Qiang Zhao, Zhang-Yu Nie, Shao-Wen Wei +2

Traditional diagnostics of black hole phase transitions rely on thermodynamic quantities defined at the event horizon or asymptotic boundary. Here, we demonstrate that the near-sin…

Waveform stability of black hole ringdown with stochastic horizon structure

Han-Wen Hu, Cheng-Jun Fang, Zong-Kuan Guo

We examine the robustness of black hole ringdown to stochastic horizon-scale structure within an effective field framework in a proof-of-principle Schwarzschild setup.Consistent wi…

Detecting gravitational wave background with equivalent configurations in the network of space based optical lattice clocks

Mingzhi Lou, Hong Su, Tao Yang +1

This paper studies the use of optical lattice clock (OLC) detector networks for detecting the stochastic gravitational-wave background (SGWB). Starting from the cross-correlation f…

gr-qc2026★ 1 cited

Numerical simulations of primordial black hole formation via delayed first-order phase transitions

Zhuan Ning, Xiang-Xi Zeng, Rong-Gen Cai +1

We perform fully nonlinear, spherically symmetric numerical simulations of superhorizon false-vacuum-domain (FVD) collapse in a coupled gravity-scalar-fluid system to study primord…

gr-qc2026★ 2 cited

Taxonomy of periodic orbits and gravitational waves in a non-rotating Destounis-Suvorov-Kokkotas black hole spacetime

Zhutong Hua, Zhen-Tao He, Jiageng Jiao +2

In this paper, we investigate periodic orbits of test particles around a non-rotating Destounis-Suvorov-Kokkotas black hole and the resulting gravitational waves. Firstly, we exami…

Light deflection in axially symmetric stationary spacetimes filled with a moving medium

Christian Pfeifer, Barbora Bezděková, Oleg Yu. Tsupko

The deflection of light rays near gravitating objects can be influenced not only by gravity itself but also by the surrounding medium. Analytical studies of such effects are possib…

Model-agnostic search of gravitational wave echoes in LVK data

Di Wu, Xi-Li Zhang, Qing-Guo Huang +1

Gravitational wave echoes offer a unique probe of the near-horizon structure of astrophysical black holes, beyond the standard "black hole spectroscopy." Theoretical waveform predi…

Critical phenomenon inside asymptotically flat black holes with spontaneous scalarization

Li Li, Ze Sun, Fu-Guo Yang

We study the interior dynamics of spontaneously scalarized black holes in Einstein-Maxwell-Scalar theory with zero cosmological constant, revealing novel critical phenomena. We dem…

Observable Gravitational Wave Strain at Second Order

Guillem Domènech, Shi Pi, Ao Wang

There is currently no rigorous definition of gravitational wave strain at second order in cosmological perturbation theory. The usual association of gravitational waves with transv…

Spherically symmetric solutions in quasi-local Einstein-Weyl gravity

Johanna Borissova, Breno L. Giacchini, Aaron Held

Quantum-gravitational effective actions with higher-derivative and non-local operators are expected to regularize the singularities of general relativity. Here we focus on quasi-lo…

Low-finesse scattering and non-stationary dispersive dynamics of gravitational wave echoes

Han-Wen Hu, Cheng-Jun Fang, Zong-Kuan Guo

We study environmental echoes induced by a weak potential barrier outside a Schwarzschild black hole. In the low-finesse limit, the time domain response is governed by a sequence o…

Explicit and covariant formula for thermodynamic volume in extended black hole thermodynamics

Yong Xiao, Yu-Xiao Liu, Yu Tian +1

In extended black hole thermodynamics, the cosmological constant and other couplings are treated as thermodynamic variables, yielding the first law $\tildeδM = T\tildeδS+Ω\tildeδJ…

gr-qc2025★ 2 cited

Various metric forms of all type D black holes and their application

Jiri Podolsky

Several recent results concerning the complete class of exact solutions to the Einstein-Maxwell- $Λ$ equations of type D with a double-aligned electromagnetic field are summarized.…

Parity violating spectral dynamics of black holes in dynamical Chern-Simons gravity

Han-Wen Hu, Chen Lan, Zong-Kuan Guo

We study how environmentally driven spectral instabilities of quasinormal modes respond to parity violating gravito-scalar coupling in black holes. Focusing on dynamical Chern-Simo…

gr-qc2025★ 6 cited

Third law of repetitive electric Penrose processes

Li Hu, Rong-Gen Cai, Shao-Jiang Wang

Recently, Ruffini et al. [Phys. Rev. Lett. 134 (2025) 8, 081403] pointed out that the repetitive Penrose process cannot drain the entire extractable energy of a Kerr black hole. In…

gr-qc2025★ 5 cited

Exact Black Hole Solutions in Bumblebee Gravity with Lightlike or Spacelike VEVS

Jia-Zhou Liu, Shan-Ping Wu, Shao-Wen Wei +1

Motivated by recent developments in Lorentz-violating theories of gravity, we obtain new black hole solutions within the framework of bumblebee gravity, where the bumblebee vector…

Fermionic Love number of Reissner-Nordström black holes

Xiankai Pang, Yu Tian, Hongbao Zhang +1

The tidal deformation of compact objects, characterised by their Love numbers, provides insights into the internal structure of neutron stars and black holes. While static bosonic…