arXiv subjects

Shi-Fa Guo

Publications and source records attributed to Shi-Fa Guo.

3 recordsLinked to original sources

arXiv2022

A braneworld model in a massive gravity

A Randall-Sundrum-like braneworld scenario is constructed in a 5D extension of the Lorentz-violating massive gravity. The gauge hierarchy problem is solved in current model. The linear perturbations are calculated, and it is found that the tensor and vector perturbations are robust and free from the ghost and tachyonic instabilities, however, the scalar perturbation is a ghost filed. After Kaluza-Klein reduction, all the tensor, vector and scalar modes are massive and possess the mass splitting of order of TeV in their respective mass spectra. The massive ground states of tensor and scalar modes propagate only along the brane, however, the vector ground state is absent in the mass spectrum. By introducing the Goldberger-Wise mechanism to stabilize the extra dimension, the 4D effective theory on the brane includes a nearly massless graviton plus three towers of very massive spin-2, spin-1 and ghost spin-0 particles.

hep-th↗

arXiv2021

Degenerate Black Rings in $D=5$ Minimal Supergravity

We consider both gauged and ungauged minimal supergravities in five dimensions and analyse the charged rotating solutions with two equal angular momenta $J$. When the electric charge $Q\sim J^{2/3}$ with some specific coefficient, we find new extremal black objects emerge that are asymptotic to either Minkowski or global AdS spacetimes and can be best described as degenerate black rings. Their near-horizon geometry is locally AdS$_3\times S^2$, where the periodic $U(1)$ fibre coordinate in $S^3$ untwists and collapses to be the degenerate part of the AdS$_3$ horizon. It turns out that there are two branches of extremal rotating black holes, starting as the extremal RN black holes of the same mass, but opposite charges. With the increasing of the angular momentum, they will join to become the same degenerate black ring, where the Gibbs free energies however are not continuous at the joining. For the same $Q(J)$ relation, we find that there is in addition a rotating soliton whose mass is smaller than the degenerate black ring.

hep-th↗

arXiv2021

Large-Charge Limit of AdS Boson Stars with Mixed Boundary Conditions

It was recently shown that charged AdS boson stars can reproduce the universal structure of the lowest scaling dimension in the subsector of a CFT with fixed large global $U(1)$ charge $Q$. Using the model consisting of Einstein-Maxwell gravity with a negative cosmological constant, coupled to a $U(1)$-charged conformally massless scalar with the fourth-order self interaction, we construct a class of charged AdS boson star solutions in the large $Q$ limit, where the scalar field obeys a mixed boundary condition, parameterized by $k$ that interpolates between the Neumann and Dirichlet boundary conditions corresponding to $k=0$ and $\infty$ respectively. By varying $k$, we numerically read off the $k$ dependence of the leading coefficient $c_{3/2}(k) \equiv \lim_{Q\rightarrow \infty} M/Q^{3/2}$. We find that $c_{3/2}(k)$ is a monotonously increasing function which grows linearly when $k$ is sufficiently small. When $k\rightarrow \infty$, $c_{3/2}(k)$ approaches the maximal value at a decreasing rate given by $k^{-3/2}$ . We also obtain a close form expression that fits the numerical data for the entire range of $k$ within $10^{-4}$ accuracy.

hep-th↗