arXiv subjects

Hao-Jie Lin

Publications and source records attributed to Hao-Jie Lin.

6 recordsLinked to original sources

arXiv2026

Gravitational radiations from periodic orbits around a black hole in the effective field theory extension of general relativity

The study of periodic orbits in extreme-mass-ratio inspirals is essential for understanding the dynamics of small bodies orbiting supermassive black holes. In this paper, we study the periodic orbits and their corresponding gravitational wave emissions within the framework of an effective field theory-based extension of general relativity (EFTGR), which incorporates higher-order curvature terms into the Einstein-Hilbert action. We start with a brief analysis of the modified black hole spacetime in EFTGR and examine how its parameters influence the dynamics of a massive neutral particle using the Lagrangian formalism. Focusing on the impact of the higher-order curvature terms in EFTGR, we examine the properties of periodic orbits, which are characterized by three topological integers $(z, w, v)$ that uniquely classify their trajectories. By analyzing these orbits within EFTGR, we aim to provide new insights into how strong-field deviations from general relativity may manifest in observable phenomena. We then calculate the gravitational waveforms generated by these periodic orbits, identifying potential observational signatures. Our analysis reveals a direct connection between the zoom-whirl orbital behavior of the small compact object and the gravitational waveforms it emits: higher zoom numbers lead to increasingly intricate waveform substructures. The results contribute to a clearer understanding of the dynamical features of EFTGR and open new avenues for probing black hole properties via gravitational wave detection.

gr-qc↗

arXiv2026

Scalarizations of magnetized Reissner-Nordström black holes induced by parity-violating and parity-preserving interactions

We study spontaneous scalarization of a scalar field in the magnetized Reissner--Nordström spacetime induced by parity-violating and parity-preserving interactions, represented by couplings to the electromagnetic Chern--Simons, gravitational Chern--Simons, and Gauss--Bonnet invariants, respectively. Working in the decoupling limit, we evolve scalar perturbations in the time domain and determine the critical coupling for the onset of tachyonic instability. This allows us to compare, within the same magnetized background, how the external magnetic field affects scalarization induced by parity-violating and parity-preserving interactions. We find that the magnetic field lowers the scalarization threshold in the electromagnetic and gravitational Chern--Simons channels. In the Gauss--Bonnet channel, by contrast, the effect divided into two branches: on the negative-$α$ branch in our convention, corresponding to the standard GB$^{+}$ branch, the magnitude of the critical coupling increases with the magnetic field, whereas on the positive-$α$ branch, corresponding to GB$^{-}$, the critical coupling decreases with the magnetic field but diverges in the limit of vanishing field. The magnetic field also modifies the late-time dynamics and gives rise to Melvin-like modes. When nonlinear couplings are included, the unbounded growth of the linearized theory is replaced by bounded oscillatory evolution. These results show that external magnetic fields affect scalarization induced by parity-violating and parity-preserving interactions in qualitatively different ways, and reveal a pronounced asymmetry between the two Gauss--Bonnet branches.

gr-qc↗

arXiv2025

Coulomb Drag in Altermagnets

An altermagnet is a newly discovered antiferromagnet, characterized by unique anisotropic spin-split energy bands. It has attracted tremendous interest, because of its promising potential in information storage and processing. However, measuring the distinctive spin-split energy bands arising from altermagnetism remains a challenge. Here, we propose to employ the Coulomb drag to probe altermagnetism. In the Coulomb drag, an electric current in an active layer of electron gases can induce currents in a close but well-isolated passive layer, due to interlayer Coulomb interactions. We find that the Coulomb drag effects in altermagnets are highly sensitive to the orientation of the spin-split Fermi surfaces. As a result, transverse currents can be dragged in the passive layer, leading to Hall drag effects even in absence of spin-orbit coupling, a feature quite different from all previous systems. More importantly, all the drag effects of altermagnets have unique angle dependence, which can be measured in a multi-terminal setup to serve as signatures for altermagnetism. This proposal will inspire increasing explorations on emergent magnetism.

cond-mat.mes-hall↗

arXiv2025

Probing black holes via quasinormal modes in a dark energy-induced dark matter

This study delves into the existence of dark matter around supermassive black holes in galactic cores using a novel gravitational model. By analyzing gravitational waves emitted during the ringdown phase of black holes under different field perturbations, we explore the potential for detecting dark matter. The model hypothesizes that the dark matter distribution around black hole is driven by a mechanism where dark energy endows gravitons with mass, thereby forming a new spacetime structure. Results reveal that as relevant parameters increase, the quasinormal modes (QNMs) exhibit a gradual reduction in real parts, with negative imaginary parts whose absolute values also decrease. Moreover, compared to gravitational wave signals from Schwarzschild black hole without dark matter, this system demonstrates significant differences in oscillation modes and frequencies. This achievement not only validates the self-consistency of the new gravitational model but also lays a theoretical foundation for subsequent gravitational wave detection within dark matter. Simultaneously, it provides new theoretical support for understanding the mechanism of dark energy in large-scale cosmic structures and broadens the research perspective on the relationships between black hole physics, dark matter, and dark energy.

gr-qc↗

arXiv2023

Black hole scalarizations induced by parity violations

It is well-known that parity symmetry is broken in the weak interaction but conserved for Einstein's general relativity and Maxwell's electromagnetic theory. Nevertheless, parity symmetry could also be violated in the gravitational/electromagnetic sectors if a fundamental scalar field couples to the parity-violating gravitational/electromagnetic curvature terms. Such parity-violating terms, which flip signs under reversed spatial directions, can inevitably lead to a negative effective mass squared for the scalar field perturbations near nonspherically symmetric black holes and thus are expected to trigger tachyonic instability. As illustrative examples, we show that the scalar field coupled to gravitational/electromagnetic Chern-Simons terms near a Kerr-Newmann spacetime can develop tachyonic instabilities, leading to equilibrium scalar field configurations in certain parameter regions of black holes. This instability, which is an indication of the black hole scalarization process, can occur in a broad class of nonspherically symmetric black holes and parity-violating theories.

gr-qc↗

arXiv2023

Fate of entanglement in one-dimensional fermion liquid with coherent particle loss

Quantum many-body systems and quantum devices experience the detrimental effects of noise and particle losses, necessitating their treatment as open quantum systems or, in approximation, as non-Hermitian systems. These systems exhibit nontrivial characteristics in their time evolution that differ significantly from closed systems. In this Letter, we study the dynamic properties of a one-dimensional fermionic system with adjacent-lattice particle loss. By utilizing time-dependent correlation matrix methods and bosonization techniques, we demonstrate that, as the system evolves over time, its (bipartite) von Neumann entropy exhibits a universal behavior of rapid increase due to thermalization effects at short times, independent of the effective Hamiltonian and Liouvillian spectra, even in the presence of interactions. Additionally, we show that the asymmetric non-Hermitian terms in the effective Hamiltonian caused by adjacent-lattice quantum jumps lead to left-right asymmetry of quasiparticles in momentum space, which is ubiquitous in non-Hermitian skin effects and introduces momentum-space entanglement independent of the interaction strength at early times. Our study illuminates the universal fate of non-Hermitian fermionic liquids in the open quantum context, enriching our understanding of non-Hermitian many-body systems over the entire time range. Furthermore, our findings provide valuable insights for near-term quantum devices and the quantum simulation of open systems.

quant-ph↗