Some exact solutions of the semilocal Popov equations

We study the semilocal version of Popov's vortex equations on $S^2$. Though they are not integrable, we construct two families of exact solutions which are expressed in terms of rational functions on $S^2$. One family is a trivial embedding of Liouville-type solutions of the Popov equations obtained by Manton, where the vortex number is an even integer. The other family of solutions are constructed through a field redefinition which relate the semilocal Popov equation to the original Popov equation but with the ratio of radii $\sqrt{3/2}$, which is not integrable. These solutions have vortex number $N=3n-2$ where $n$ is a positive integer, and hence $N=1$ solutions belong to this family. In particular, we show that the $N=1$ solution with reflection symmetry is the well-known $CP^1$ lump configuration with unit size where the scalars lie on $S^3$ with radius $\sqrt{3/2}$. It generates the uniform magnetic field of a Dirac monopole with unit magnetic charge on $S^2$.Comment: 13 pages, minor corrections, version published in Phys.Lett.

Low Energy Dynamics of Monopoles in Supersymmetric Yang-Mills Theories with Hypermultiplets

We derive the low energy dynamics of monopoles and dyons in N=2 supersymmetric Yang-Mills theories with hypermultiplets in arbitrary representations by utilizing a collective coordinate expansion. We consider the most general case that Higgs fields both in the vector multiplet and in the hypermultiplets have nonzero vacuum expectation values. The resulting theory is a supersymmetric quantum mechanics which has been obtained by a nontrivial dimensional reduction of two-dimensional (4,0) supersymmetric sigma models with potentials.Comment: 17pages, LaTeX, minor changes, references added, version published in JHE

Holographic Entanglement Entropy of Anisotropic Minimal Surfaces in LLM Geometries

We calculate the holographic entanglement entropy (HEE) of the $\mathbb{Z}_k$ orbifold of Lin-Lunin-Maldacena (LLM) geometries which are dual to the vacua of the mass-deformed ABJM theory with Chern-Simons level $k$. By solving the partial differential equations analytically, we obtain the HEEs for all LLM solutions with arbitrary M2 charge and $k$ up to $\mu_0^2$-order where $\mu_0$ is the mass parameter. The renormalized entanglement entropies are all monotonically decreasing near the UV fixed point in accordance with the $F$-theorem. Except the multiplication factor and to all orders in $\mu_0$, they are independent of the overall scaling of Young diagrams which characterize LLM geometries. Therefore we can classify the HEEs of LLM geometries with $\mathbb{Z}_k$ orbifold in terms of the shape of Young diagrams modulo overall size. HEE of each family is a pure number independent of the 't Hooft coupling constant except the overall multiplication factor. We extend our analysis to obtain HEE analytically to $\mu_0^4$-order for the symmetric droplet case.Comment: 15 pages, 1 figur

Transparentizing Black Holes to Eternal Traversable Wormholes

We present the gravity description of evaporating black holes that end up with eternal traversable wormholes where every would-be behind horizon degree is available in asymptotic regions. The transition is explicitly realized by a time-dependent bulk solution in the two-dimensional Einstein-dilaton gravity. In this solution, the initial AdS$_2$ black hole is evolved into an eternal traversable wormhole free of any singularity, which may be dubbed as transparentization of black holes to eternal traversable wormholes. The bulk construction completely matches with the boundary description governed by the Schwarzian boundary theory. We also obtain solutions describing eternal traversable wormholes as well as excitations by an additional matter and graviton oscillations on eternal traversable wormholes, which show that the eternal traversable wormhole states are gapped and non-chaotic. Embedding the 2d solution into a 4d traversable wormhole connecting two magnetically charged holes, we discuss 4d scattering of a wave incident upon one end of the traversable wormhole.Comment: 1+34 pages, 5 figures, 4 tables; v2: various typos fixed, Ref. added; v3: a few typos fixed, published versio