arXiv subjects

Chen-Hsu Chien

Publications and source records attributed to Chen-Hsu Chien.

4 recordsLinked to original sources

arXiv2026

Holomorphic Conformal Cartan Geometry: Conformal Gravity, Twistors, and Ambitwistors

Four-dimensional conformal gravity, twistor theory, and ambitwistor theory are reviewed within the unified framework of holomorphic conformal Cartan geometry. Starting from the spinorial representation of the geometry, the normal $\mathfrak{sl}(4,\mathbb{C})$-valued Cartan connection, its curvature $2$-form, and the associated tractor bundles are systematically formulated. Evaluated on the real Lorentzian slice, the quadratic curvature action is shown to reproduce four-dimensional Weyl--Bach conformal gravity upon fixing a Weyl gauge. Local twistor and dual twistor bundles are constructed as associated spin tractor bundles, illustrating how parallel transport yields the classical incidence relations in flat space and chiral integrability constraints in curved backgrounds: anti-self-duality for $α$-surfaces and self-duality for $β$-surfaces. Furthermore, by pairing local twistors and dual twistors via an invariant canonical pairing, ambitwistor space is shown to parameterize complex null geodesics and symmetrically accommodate both left- and right-handed Weyl curvatures. This framework establishes a direct gauge-theoretic bridge linking conformal Cartan geometry to twistor and ambitwistor theories.

math-ph↗

arXiv2026

Quantum Suppression of Mass Inflation in Reissner-Nordström Interiors via Wheeler-DeWitt Equation

We construct a canonical quantization, the Wheeler-DeWitt equation, of the interior geometry of static and spherically symmetric black holes in Einstein-Maxwell-$Λ$ framework, focusing on Reissner-Nordström. The wave function of the Wheeler-DeWitt equation for the Reissner-Nordström black hole is set to be on-shell and exhibiting exponential damping away from the classical locus. Horizon boundary conditions for the wave function generate two regimes: a single inward mode from event horizon yields monotonic decay, while superpositions produce either a quantum bounce (single time arrow) or interference-driven annihilation-to-nothing (two time arrows). We show that these are generic features of static black hole interiors. Furthermore, the wave function of the Schwarzschild black hole, obtained as the charge-neutral limit of the Reissner-Nordström black hole, is monotonically decaying and no longer unbounded. Moreover, this framework unifies classical and quantum interiors, suggests a quantum gravitational suppression to the mass inflation, and motivates extensions to Kerr and regular black holes.

gr-qc↗

arXiv2023

Wheeler-DeWitt equation beyond the cosmological horizon: Annihilation to nothing, infinity avoidance, and loss of quantum coherence

We investigate the Schwarzschild-(anti) de Sitter spacetime with the anisotropic metric ansatz. The Wheeler-DeWitt equation for such a metric is solved numerically. In the presence of the cosmological constant $Λ$, we show that two classical wave packets can be annihilated inside the black hole horizon, i.e., the annihilation-to-nothing scenario. It is interesting that the Wheeler-DeWitt equation can be extended to the asymptotic de Sitter spacetime outside the cosmological horizon. Surprisingly, the only bounded nontrivial wave function beyond the cosmological horizon satisfies the DeWitt boundary condition, i.e., the wave function must vanish at a certain finite radius. This might be an alternative explanation to the classicalization of quantum fluctuations in the de Sitter space, where this topic is also related to decoherence.

gr-qc↗

arXiv2021

The reheating constraints to natural inflation in Horndeski gravity

For the subclass of Horndeski theory of gravity, we investigate the effects of reheating on the predictions of natural inflation. In the presence of derivative self-interaction of a scalar field and its kinetic coupling to the Einstein tensor, the gravitational friction to inflaton dynamics is enhanced. As a result, the tensor-to-scalar ratio $r$ is suppressed. We place the observational constraints on a natural inflation model and show that the model is now consistent with the observational data for some plausible range of the model parameter $Δ$, mainly due to the suppressed tensor-to-scalar ratio. To be consistent with the data at the $1σ$ ($68\%$ confidence) level, a slightly longer $N_k\gtrsim60$ duration of inflation than usually assumed is preferred. Since the duration of inflation, for any specific inflaton potential, is related to reheating parameters, including the duration $N_{re}$, temperature $T_{re}$, and equation-of-state $ω_{re}$ parameter during reheating, we imposed the effects of reheating to the inflationary predictions to put further constraints. The results show that the duration of inflation $N_k$ is affected by considerations of reheating, mainly by the $ω_{re}$ and $T_{re}$ parameters. If reheating occurs instantaneously for which $N_{re}=0$ and $ω_{re}=1/3$, the duration of inflation is estimated to be $N_k\simeq57$, where the exact value is less sensitive to the model parameter $Δ$ compatible with the CMB data. The duration of inflation is longer (or shorter) than $N_k\simeq57$ for the equation of state larger (or smaller) than 1/3 hence $N_{re}\neq0$. The maximum temperature at the end of reheating is $T_{re}^\text{max}\simeq3\times 10^{15}$ GeV, which corresponds to the instantaneous reheating. The low reheating temperature, as low as a few MeV, is also possible when $ω_{re}$ is closer to $1/3$.

astro-ph.CO↗