arXiv subjects

Cendikiawan Suryaatmadja

Publications and source records attributed to Cendikiawan Suryaatmadja.

6 recordsLinked to original sources

arXiv2026

Charged soliton--black hole phase transitions in three-dimensional Einstein--Gauss--Bonnet gravity

We construct a magnetic soliton by double Wick rotating the static electrically charged black hole in three-dimensional Einstein--Gauss--Bonnet gravity. We match the boundary metrics and Maxwell sources under the chosen boundary condition and compute the difference of the renormalized Euclidean actions. Because the Maxwell potential grows logarithmically at infinity, the chosen finite Maxwell boundary term changes both the fixed Maxwell source and the renormalized action. The charge contributions for both the soliton and the black hole appear with plus signs in $ΔI^{(c_{\mathrm{fin}})}$. For the grand-canonical boundary condition $c_{\mathrm{fin}}=1$, the black-hole and soliton branches can cross with different slopes. For the example considered below, the black-hole branch satisfying the response conditions ends at a maximum temperature, and the coexistence curve has a $T\to0^+$ endpoint at two opposite values of the spatial Maxwell source. At a nonextremal crossing, the entropy difference is $S_b-S_s=S_b$. For these two static solutions, equality of both current components requires both charges to vanish.

gr-qc↗

arXiv2026

Propagation and horizon formation in Einstein--Gauss--Bonnet scalar collapse. I. Characteristic conditions, bounds and formation

We study scalar collapse in five- and six-dimensional Einstein--Gauss--Bonnet gravity with positive coupling, treated as an exact classical theory. On spherical scalar backgrounds, the characteristic conditions of the tensor, vector and scalar gravitational sectors reduce to inequalities in two local invariants: $K=1+\tildeαF/R^2$, which compares the enclosed mass with the areal radius $R$, and a scalar-gradient invariant $j$. In five dimensions they imply $R_h^2>\tildeα$ for the areal radius $R_h$ of a regular marginal sphere on the GR branch and the sharp bound $\tildeα^2\mathcal R_{abcd}\mathcal R^{abcd}<28$ for nonnegative mass. For initially untrapped five-dimensional spherical data with a regular center, a bound on $K$ alone ensures smooth continuation on compact domains of dependence, so any first characteristic loss occurs on a smooth background, and a marginal sphere formed before any loss forces a later loss. Complete smooth data form marginal spheres at every allowed radius with mass arbitrarily close to its sharp lower bound; in six dimensions radius and mass can both be arbitrarily small. Without spherical symmetry, complete initial data with weak curvature contain, at sufficiently large scale, outermost strictly stable marginal surfaces with prescribed $S^3$ geometries satisfying a spectral condition; Berger surfaces among them have arbitrarily small area at fixed mass. Their formation from untrapped data is left open. Near a contracting homogeneous core, exact nonspherical developments of smooth constrained data converging with every derivative have bounded curvature but, after the core's characteristic loss, a fixed discrepancy in a geometric tidal record. Classical existence, local geometric uniqueness and continuity of this pointwise record cannot all be guaranteed on a common observation region. A companion paper treats narrow incoming pulses.

gr-qc↗

arXiv2026

Black Holes and Scalar Propagation in Three-Dimensional Einstein--Gauss--Bonnet Gravity

We derive an analytic black-hole family in three-dimensional scalar--tensor Einstein--Gauss--Bonnet gravity with positive coupling. A single implicit equation determines the static circular metric and a scalar linear in time. We show that these solutions exhaust regular nonextremal exteriors with the stated AdS boundary conditions and a fixed nonzero coefficient of time in the scalar. The coupled metric and scalar perturbations have one propagating degree of freedom. On one branch, its kinetic coefficient is positive, its equation is hyperbolic throughout the exterior, and its bulk spatial energy is positive for perturbations of compact support. Scalar signals can cross the metric horizon outward, so exterior evolution needs information from the interior. For linear perturbations with the original metric and scalar boundary values fixed, nonzero compact initial master displacements with zero velocity can evolve only until their first contact with the AdS boundary. We derive this restriction from the original metric and scalar equations.

gr-qc↗

arXiv2026

Acceleration in 3D Einstein-Gauss-Bonnet Gravity

We present a new class of exact solutions in Einstein-Gauss-Bonnet gravity in 2+1 dimensions that generalize the C-metric. This set of metrics equals the C-metric multiplied by a factor which, along with the massless scalar field, depends on a single variable whose value governs the structure of the spacetime. As in Einstein gravity there are three classes of metrics, but within each class we find six distinct subclasses of solutions. After discussing their basic structure, we concentrate only on one subclass that is locally AdS. In the zero-coupling limit, this subclass of solutions not only remains well defined and recovers the C-metric but also encompasses two previously unknown representations of the AdS spacetime. Furthermore, we establish the existence of a domain wall and delineate its energy conditions. We also find new classes of solutions of non-constant curvature, whose interpretation remains to be understood.

gr-qc↗

arXiv2023

Signatures of Rotating Black Holes in Quantum Superposition

A new approach for operationally studying the effects of spacetime in quantum superpositions of semiclassical states has recently been proposed by some of the authors. This approach was applied to the case of a (2+1)-dimensional Bañados-Teitelboim-Zanelli (BTZ) black hole in a superposition of masses, where it was shown that a two-level system interacting with a quantum field residing in the spacetime exhibits resonant peaks in its response at certain values of the superposed masses. Here, we extend this analysis to a mass-superposed rotating BTZ black hole, considering the case where the two-level system co-rotates with the black hole in a superposition of trajectories. We find similar resonances in the detector response function at rational ratios of the superposed outer horizon radii, specifically in the case where the ratio of the inner and outer horizons is fixed. This suggests a connection with Bekenstein's seminal conjecture concerning the discrete horizon spectra of black holes in quantum gravity, generalized to the case of rotating black holes. Our results suggest that deeper insights into quantum-gravitational phenomena may be accessible via tools in relativistic quantum information and curved spacetime quantum field theory.

gr-qc↗

arXiv2022

Entanglement Harvesting of Inertially Moving Unruh-DeWitt Detectors in Minkowski Spacetime

We investigate the effects of relative motion on entanglement harvesting by considering a pair of Unruh-Dewitt detectors moving at arbitrary, but independent and constant velocities, both linearly interacting with the vacuum scalar field. Working within the weak coupling approximation, we find that the Negativity is a (non-elementary) function of the relative velocity of the detectors, as well as their energy gaps and minimal separation. We find parameter regions where Negativity increases with velocity up to a maximum and then decreases, reaching zero at some sublight velocity. At any given relative velocity, the harvested entanglement is inversely correlated with the detector energy gap (at sufficiently high values) and the distance of closest approach of two detectors.

quant-ph↗