In this work, we address a foundational challenge in quantum field theory on curved spacetime by developing a consistent framework in spherically symmetric loop quantum gravity. We introduce a methodology for defining meaningful superpositions of quantum geometry and matter states near the semiclassical apparent horizon. This is achieved by identifying a restricted subspace of the...
Beyond general relativity, regular black-hole geometries and modified cosmologies are often constructed independently, raising the question of whether black holes, gravitational collapse, and cosmology can still arise as different regimes of a common gravitational dynamics. We answer this question by showing that, within the covariant spherically symmetric effective Hamiltonian framework, the...
We study the dynamics of the Bianchi I universe in modified loop quantum cosmology (mLQC-I) and uncover a robust mechanism for isotropization: the shear is dynamically suppressed after the bounce and decays rapidly in the quantum postbounce regime, independently of the equation of state of standard matter sources. This naturally drives the Universe toward a homogeneous and isotropic expanding...
Developing covariant effective descriptions of quantum-corrected black holes is an important challenge in loop quantum gravity (LQG). In this talk, I will present an LQG-inspired effective action in spherical symmetry that admits the quantum Oppenheimer–Snyder (q-OS) black hole as a vacuum solution. Starting from a two-dimensional dilaton gravity framework obtained by integrating out the...
We study the scalarization of the entire Bardeen spacetime which is constructed from a nonlinear magnetic monopole. For the pure Bardeen model, it is well known that there exist not only the general horizonless, nonsingular Bardeen spacetime solutions but also regular black hole (BH) solutions. When considering the Bardeen model coupled to a scalar field, we find that under the premise of...
This is a work about the complex conformal Kähler structure and the related duality symmetry of Plebański-Demiański class, a kind of type-D spacetime. We reviewed the complex metric and complex Kähler structure of complex spacetimes, which has the complex valued metric and almost complex structure as well as the related potential function. We find a SO(2, C) duality transformation of...
We use neural ODEs and state-of-the-art lattice QCD thermodynamics to calibrate a holographic Einstein-Maxwell-Dilaton model with Gauss-Bonnet corrections. The model quantitatively reproduces the equation of state at zero and finite baryon chemical potential and predicts the phase structure in the T-mu_B plane, a temperature-dependent ratio of shear viscosity over entropy, and a peaked ratio...
We investigate the timelike entanglement first law in holographic conformal field theories whose bulk dual is Lovelock gravity. Using the double Wick rotation formulation of timelike entanglement entropy together with the Jacobson-Myers entropy functional, we compute the linear variation of holographic timelike entanglement entropy for hyperbolic subregions. For cubic Lovelock gravity, we...
Entanglement harvesting transfers quantum field correlations to localized probes, yet whether these correlations can alter stable strategic behavior has remained unclear. We formulate a quantum-input game in which two Unruh–DeWitt detectors harvest vacuum entanglement from a free massless scalar field in $(3+1)$-dimensional Minkowski spacetime. A referee converts this state into payoffs using...
We present a holographic calculation of the semileptonic decays $B\to D$ and $B_s\to D_s$ within the AdS/QCD Softwall Model. Heavy-light mesons are described by normalizable bulk modes, while the flavor-changing current $J_\text{EW}^\mu=\bar{c}\,\gamma^\mu\,b$ is associated with a massless bulk vector field, motivated by the UV scaling dimension $\Delta=3$ of the QCD current. An effective...
We describe a bounded search for local and global anomaly-free six-dimensional $(1,0)$ models with tensor number $T=1$ and gauge group containing a diagonal abelian factor $U(1)_{R+}$. The abelian factor is the diagonal combination of the usual gauged $U(1)_R$ and a $U(1)\subset Sp(n_H)$ acting on hypermultiplets. We have searched for locally and globally anomaly-free $G_1\times U(1)_{R+}$ and...
Higher-derivative and nonlocal gravity models arise in various approaches to quantum gravity, either as candidates for renormalizable theories of gravity or as effective low-energy descriptions. In this talk, we present several recent results on classical solutions in higher-derivative gravity, focusing on the possibility of resolving the black-hole singularity present in solutions of general...
Quantum-gravity models often provide effective background dynamics, while cosmological observables depend on the dynamics of inhomogeneous perturbations. I will discuss a Hamiltonian framework for bridging this gap. Requiring consistent local evolution strongly constrains how a modified homogeneous or symmetric dynamics can be completed into a spatial theory. The resulting Hamiltonian...
We consider Bianchi IX dynamics of a Universe filled with a massless phantom field. Such an exotic matter source enables regimes impossible in vacuum or with a standard scalar field. In particular, two Kasner indices of BKL oscillations can be simultaneously negative, and the absolute value of a negative index can be large. We describe the consequences of these features and explain the nature...
Can the geometry hidden behind a black hole's event horizon be reconstructed from its exterior quasinormal-mode spectrum? In this talk, I will explore how high-overtone quasinormal modes encode information about black hole interiors. We show that distinct power-law corrections to the spectrum, obtained through angular-momentum and scalar-mass responses, allow the temporal and angular Kasner...
We establish a general no-inner horizon theorem for a wide class of static anisotropic black holes in Einstein gravity. As an application, we demonstrate that a large variety of black holes which possess homogeneous but anisotropic three-dimensional horizons can not have inner horizons. Our theorem is consistent with some previously known results, implying an underlying mechanism that certain...
Black hole is an interesting physical object which is both a thermodynamical system and nest of chaos. In this talk, I will firstly introduce the conformal anomaly corrections on the black hole geometry in 4d spherical symmetric spacetime. After introducing the black hole solution, I will discuss the thermodynamics and chaotic properties of this black hole. We investigate the phase transition...
