arXiv subjects
Publications and source records attributed to Yoonbai Kim.
We study the first-order phase transition in a model of scalar field with $O(3)$ symmetry coupled to gravity, and, in high temperature limit, discuss the existence of new bubble solution with a global monopole at the center of the bubble.
Spontaneous breakdown of the continuous symmetry is studied in the framework of discretized light-front quantization. We consider linear sigma model in 3+1 dimensions and show that the careful treatment of zero modes together with the regularization of the theory by introducing NG boson mass leads to the correct description of Nambu-Goldstone phase on the light-front.
We show that the Nambu-Goldstone(NG) boson restricted on the light-front(LF) can only exist if we regularize the theory by introducing the explicit breaking NG-boson mass $m_π$. The NG-boson zero mode, when integrated over the LF, must have a singular behavior $\sim 1/m^2_π$ in the symmetric limit of $m^2_π\rightarrow 0$. In the discretized LF quantization this peculiarity is clarified in terms of the zero-mode constraints in the linear $σ$ model. The LF charge annihilates the vacuum, while it is not conserved in the symmetric limit in the NG phase.
We reformulate the Thirring model in $D$ $(2 \le D < 4)$ dimensions as a gauge theory by introducing $U(1)$ hidden local symmetry (HLS) and study the dynamical mass generation of the fermion through the Schwinger-Dyson (SD) equation. By virtue of such a gauge symmetry we can greatly simplify the analysis of the SD equation by taking the most appropriate gauge (``nonlocal gauge'') for the HLS. In the case of even-number of (2-component) fermions, we find the dynamical fermion mass generation as the second order phase transition at certain fermion number, which breaks the chiral symmetry but preserves the parity in (2+1) dimensions ($D=3$). In the infinite four-fermion coupling (massless gauge boson) limit in (2+1) dimensions, the result coincides with that of the (2+1)-dimensional QED, with the critical number of the 4-component fermion being $N_{\rm cr} = \frac{128}{3π^{2}}$. As to the case of odd-number (2-component) fermion in (2+1) dimensions, the regularization ambiguity on the induced Chern-Simons term may be resolved by specifying the regularization so as to preserve the HLS. Our method also applies to the (1+1) dimensions, the result being consistent with the exact solution. The bosonization mechanism in (1+1) dimensional Thirring model is also reproduced in the context of dual-transformed theory for the HLS.
There has been considerable interest in the possible cosmic string configurations and Y. Yang has recently derived intriguing obstructions to the existence of cylindrically symmetric solutions in the Bogomol'nyi critical phase of the Einstein-Maxwell-Higgs system. In this comment, we would like to mention some earlier results and recent progress which were not reflected there but are important in connection with the obstructions he claimed. Some of his obstructions are not consistent with the ealier results. Also, we give a new condition stronger than those found before.
The first-order phase transition of $O(3)$ symmetric model is considered in the limit of high temperature. It is shown that this model supports a new bubble solution where the global monopole is formed at the center of the buble in addition to the ordinary $O(3)$ bubble. Though the free energy of it is larger than that of normal bubble, the production rate can considerably large at high temperatures.
The Abelian Higgs model with or without external particles is considered in curved space. Using the dual transformation, we rewrite the model in terms of dual gauge fields and derive the Bogomol'nyi-type bound. We examine cylindrically symmetric solutions to Einstein equations and the first-order Bogomol'nyi equations, and find vortex solutions and vortex-particle composites which lie on the spatial manifold with global geometry described by a cylinder asymptotically or a two sphere in addition to the well-known cone.
We consider vortex dynamics in self-dual Chern-Simons Higgs systems. We show that the naive Aharanov-Bohm phase is the inverse of the statistical phase expected from the vortex spin, and that the self-dual configurations of vortices are degenerate in energy but not in angular momentum. We also use the path integral formalism to derive the dual formulation of Chern-Simons Higgs systems in which vortices appear as charged particles. We argue that besides the electromagnetic interaction, there is an additional interaction between vortices, the so-called Magnus force, and that these forces can be put together into a single `dual electromagnetic' interaction. This dual electromagnetic interaction leads to the right Aharanov-Bohm phase. We also derive and study the effective action for slowly moving vortices, which contains terms both linear and quadratic in the vortex velocity.