Surplus Solid Angle: Toward Astrophysical Test of Horava-Lifshitz Gravity (2009)
Kim, Sung-Soo, Kim, Taekyung, Kim, Yoonbai
We consider electrostatic field of a point charge coupled to Horava-Lifshitz gravity and find an exact solution describing the space with a surplus (or deficit) solid angle. Although, theoretically...
Coupling between M2-branes and Form Fields (2009)
Kim, Yoonbai, Kwon, O-Kab, Nakajima, Hiroaki, Tolla, D. D.
In the context of low-energy effective theory of multiple M2-branes, we construct the interaction terms between the world-volume fields of M2-branes and the antisymmetric tensor fields of three- and...
Vortex-type Half-BPS Solitons in ABJM Theory (2009)
Kim, Chanju, Kim, Yoonbai, Kwon, O-Kab, Nakajima, Hiroaki
We study Aharony-Bergman-Jafferis-Maldacena (ABJM) theory without and with mass deformation. It is shown that maximally supersymmetry preserving, D-term, and F-term mass deformations of single mass...
Inflation on a Pair of D3-brane and D3bar-brane in Klebanov-Strassler Background (2009)
Kim, Yoonbai, Nakajima, Hiroaki, Ryu, Kyungha, Kim, Hang Bae
We explain how to obtain Klabanov-Strassler solution in the low-energy limit of type IIB superstring theory and describe slow-roll inflation on the system of parallely-separated D3-brane and...
Cho, Inyong, Kim, Taekyung, Kim, Yoonbai
We investigate the BPS configuration of the multi D-vortices produced from the D2${\bar {\rm D}}$2 system. Based on the DBI-type action with a Gaussian-type runaway potential for a complex tachyon...
Tachyon Vacuum Solution in Open String Field Theory with Constant B Field (2008)
Ishida, Akira, Kim, Chanju, Kim, Yoonbai, Kwon, O-Kab, Tolla, D. D.
We show that Schnabl's tachyon vacuum solution is an exact solution of the equation of motion of Witten's open bosonic string field theory in the background of constant antisymmetric two-form field....
Charged Black Cosmic String (2008)
Nakwoo Kim, Yoonbai Kim, Kyoungtae Kimm
Global U(1) strings with cylindrical symmetry are studied in anti-de Sitter spacetime. According as the magnitude of negative cosmological constant, they form regular global cosmic strings, extremal...
Negative-Tension Branes and Tensionless 1/2 Brane in Boundary Conformal Field Theory (2008)
Ishida, Akira, Kim, Chanju, Kim, Yoonbai, Kwon, O-Kab
In the framework of boundary conformal field theory we consider a flat unstable D$p$-brane in the presence of a large constant electromagnetic field. Specifically, we study the case that the...
Lower Dimensional Branes in Boundary Conformal Field Theory (2008)
Ishida, Akira, Kim, Yoonbai, Kim, Chanju, Kwon, O-Kab
In the presence of constant background electromagnetic fields, we discuss three types of exactly marginal boundary tachyon operators for static kinks in boundary conformal field theory. Functional...
Global Vortex and Black Cosmic String (2007)
Nakwoo Kim, Yoonbai Kim, Kyoungtae Kimm
We study global vortices coupled to (2+1) dimensional gravity with negative cosmological constant. We found nonsingular vortex solutions in OE 4 -theory with a broken U(1) symmetry, of which the...
Production of Global Monopoles through the Nucleation of O(3) Bubbles (2007)
First-order cosmological phase transitions are considered in the models with an O(3)-symmetric scalar field, in the high temperature limit. It is shown that a global monopole can be produced at the...
Relativistic Dynamics of Multi-BPS D-vortices and Straight BPS D-strings (2007)
Cho, Inyong, Kim, Taekyung, Kim, Yoonbai, Ryu, Kyungha
Moduli space dynamics of multi-D-vortices from D2${\bar {\rm D}}$ (equivalently, parallel straight D-strings from D3${\bar {\rm D}}$3) is systematically studied. For the BPS D-vortices, we show...
BPS Limit of Multi- D- and DF-strings in Boundary String Field Theory (2007)
Go, Gyungchoon, Ishida, Akira, Kim, Yoonbai
A BPS limit is systematically derived for straight multi- D- and DF-strings from the D3D3bar system in the context of boundary superstring field theory. The BPS limit is obtained in the limit of thin...
Cosmic D- and DF-strings from D3Dbar3: Black Strings and BPS Limit (2006)
Kim, Taekyung, Kim, Yoonbai, Kyae, Bumseok, Lee, Jungjai
We study D- and DF-strings in a D3${\bar {\rm D}}3$ system by using Dirac-Born-Infeld type action. In the presence of an electric flux from the transverse direction, we discuss gravitating thick...
Cosmological Aspects of the D-brane World (2006)
Cho, Inyong, Chun, Eung Jin, Kim, Hang Bae, Kim, Yoonbai
The D-brane world is an idea that we are living on the D-brane imbedded in a 10- or 11-dimensional spacetime of string theories, aiming at the construction of realistic models from string theories....
String Cosmology of the D-brane Universe (2006)
Cho, Inyong, Chun, Eung Jin, Kim, Hang Bae, Kim, Yoonbai
We analyze homogeneous anisotropic cosmology driven by the dilaton and the self-interacting ``massive'' antisymmetric tensor field which are indispensable bosonic degrees with the graviton in the...
Tachyon Kinks in Boundary String Field Theory (2006)
Kim, Chanju, Kim, Yoonbai, Kwon, O-Kab, Yee, Ho-Ung
We study tachyon kinks with and without electromagnetic fields in the context of boundary string field theory. For the case of pure tachyon only an array of kink-antikink is obtained. In the presence...
Homogeneous Rolling Tachyons in Boundary String Field Theory (2006)
Ishida, Akira, Kim, Yoonbai, Kouwn, Seyen
We study decay of a flat unstable D$p$-brane in the context of boundary string field theory action. Three types of homogeneous rolling tachyons are obtained without and with Born-Infeld type...
Cosmological implication of antisymmetric tensor field on D-brane (2006)
Cho, Inyong, Chun, Eung Jin, Kim, Hang Bae, Kim, Yoonbai
We discuss the cosmological implications of an antisymmetric tensor field when it experiences a kind of ``Higgs mechanism,'' including nonlocal interaction terms, on D-branes. Even when a huge...
Is the Chinese Renminbi Undervalued? (2006)
This article seeks to investigate whether the renminbi (RMB) has become grossly undervalued by empirically estimating China's equilibrium real exchange rate for the period 1978–2002. A reduced form...
DF-strings from D3${\bar {\bf D}}$3 as Cosmic Strings (2005)
Cho, Inyong, Kim, Yoonbai, Kyae, Bumseok
We study Dirac-Born-Infeld type effective field theory of a complex tachyon and U(1)$\times$U(1) gauge fields describing a D3${\bar {\rm D}}$3 system. Classical solutions of straight global and local...
BPS D-branes from an Unstable D-brane (2005)
Kim, Chanju, Kim, Yoonbai, Kwon, Hwang-hyun, Kwon, O-Kab, Lee, Chong Oh
We search for exact tachyon kink solutions of DBI type effective action describing an unstable D-brane with worldvolume gauge field turned in both the flat and a curved background. There are various...
Global and Local D-vortices (2005)
Kim, Yoonbai, Kyae, Bumseok, Lee, Jungjai
Codimension-two objects on a system of brane-antibrane are studied in the context of Born-Infeld type effective field theory with a complex tachyon and U(1)$\times$U(1) gauge fields. When the radial...
BPS D-branes from an Unstable D-brane in a Curved Background (2005)
Kim, Chanju, Kim, Yoonbai, Kwon, Hwang-hyun, Kwon, O-Kab
We find exact tachyon kink solutions of DBI type effective action describing an unstable D5-brane with worldvolume gauge field turned on in a curved background. The background of interest is the...
Cosmology of Antisymmetric Tensor Field in D-brane Universe (2005)
Chun, Eung Jin, Kim, Hang Bae, Kim, Yoonbai
We analyze homogeneous, anisotropic cosmology driven by a self-interacting ``massive'' antisymmetric tensor field $B_{\mu\nu}$ which is present in string theories with D-branes. Time-dependent...
Exact Rolling Tachyon in Noncommutative Field Theory (2005)
We study the exact rolling tachyon solutions in DBI type noncommutative field theory with a constant open string metric and noncommutative parameter on an unstable D$p$-brane. Functional shapes of...
Domain Walls in Noncommutative Field Theories (2004)
Kim, Yoonbai, Kwon, O-Kab, Lee, Chong Oh
We study kinks in a wide class of noncommutative (NC) field theories. We find rich structure of the static kinks in DBI type NC tachyon action for an unstable D$p$-brane with general constant open...
Noncommutative Tachyon Kinks as D$(p-1)$-branes from Unstable D$p$-brane (2004)
Banerjee, Rabin, Kim, Yoonbai, Kwon, O-Kab
We study noncommutative (NC) field theory of a real NC tachyon and NC U(1) gauge field, describing the dynamics of an unstable D$p$-brane. For every given set of diagonal component of open string...
Unstable D-branes and String Cosmology (2004)
Kim, Chanju, Kim, Hang Bae, Kim, Yoonbai, Kwon, O-Kab, Lee, Chong Oh
Cosmological implication of rolling tachyons is reported in the context of effective field theory. With a brief review of rolling tachyons in both flat and curved spacetimes, we study the string...
Tubular D-branes in Salam-Sezgin Model (2004)
Kim, Chanju, Kim, Yoonbai, Kwon, O-Kab
We study DBI-type effective theory of an unstable D3-brane in the background manifold R^{1,1} x M_2 where M_2 is an arbitrary two-dimensional manifold. We obtain an exact tubular D2-brane solution of...
Scalar Hair of Global Defect and Black Brane World (2004)
We consider a complex scalar field in (p+3)-dimensional bulk with a negative cosmological constant and study global vortices in two extra-dimensions. We reexamine carefully the coupled scalar and...
Black Brane World from Gravitating Half $\sigma$-lump (2004)
Kim, Donghyun, Kim, Yoonbai, Lee, JungJai
We study O($N+1$) nonlinear $\sigma$-model in $(p+1+N)$-dimensional curved spacetime with negative cosmological constant, and find a new $\sigma$-lump solution with half-integer winding and divergent...
Tachyon Tube and Supertube (2003)
Kim, Chanju, Kim, Yoonbai, Kwon, O-Kab, Yi, Piljin
We search for tubular solutions in unstable D3-brane. With critical electric field E=1, solutions representing supertubes, which are supersymmetric bound states of fundamental strings, D0-branes, and...
Brane World of Warp Geometry: An Introductory Review (2003)
Kim, Yoonbai, Lee, Chong Oh, Lee, Ilbong, Lee, JungJai
Basic idea of Randall-Sundrum brane world model I and II is reviewed with detailed calculation. After introducing the brane world metric with exponential warp factor, metrics of Randall-Sundrum...
Tachyon Kinks on Unstable Dp-branes (2003)
Kim, Chanju, Kim, Yoonbai, Kwon, O-Kab, Lee, Chong Oh
In the context of tachyon effective theory coupled to Born-Infeld electromagnetic fields, we obtain all possible singularity-free static flat configurations of codimension one on unstable Dp-branes....
Kim, Chanju, Kim, Yoonbai, Lee, Chong Oh
We study Born-Infeld type tachyonic effective action of unstable D2-brane with a runaway potential and find rich structure of static regular solitonic solutions. There exists only periodic array of...
Classical stability of stringy wormholes in flat and AdS spaces (2003)
Kim, Jin Young, Kim, Yoonbai, Hetrick, James E.
We study small fluctuations of the stringy wormhole solutions of graviton-dilaton-axion system in arbitrary dimensions. We show under O($d$)-symmetric harmonic perturbation that the Euclidean...
Cosmology of Rolling Tachyon (2003)
Kim, Chanju, Kim, Hang Bae, Kim, Yoonbai, Kwon, O-Kab
We study dynamics of rolling tachyon and Abelian gauge field on unstable D-branes, of which effective action is given by Born-Infeld type nonlocal action. Possible cosmological evolutions are also...
Electromagnetic String Fluid in Rolling Tachyon (2003)
Kim, Chanju, Kim, Hang Bae, Kim, Yoonbai, Kwon, O-Kab
We study Born-Infeld type effective action for unstable D3-brane system including a tachyon and an Abelian gauge field, and find the rolling tachyon with constant electric and magnetic fields as the...
Classical Geometry of De Sitter Spacetime : An Introductory Review (2002)
Kim, Yoonbai, Oh, Chae Young, Park, Namil
Classical geometry of de Sitter spacetime is reviewed in arbitrary dimensions. Topics include coordinate systems, geodesic motions, and Penrose diagrams with detailed calculations.
Chiral primary cubic interactions from pp-wave supergravity (2002)
Kiem, Youngjai, Kim, Yoonbai, Park, Jaemo, Ryou, Cheol
We explicitly construct cubic interaction light-cone Hamiltonian for the chiral primary system involving the metric fields and the self-dual four-form fields in the IIB pp-wave supergravity. The...
Rolling Tachyons in String Cosmology (2002)
Kim, Chanju, Kim, Hang Bae, Kim, Yoonbai
We study the role of rolling tachyons in the cosmological model with dilatonic gravity. In the string frame, flat space solutions of both initial-stage and late-time are obtained in closed form. In...
Vacuum Structure and Global Strings with Conical Singularities (2002)
Kim, Yoonbai, Kwon, O-Kab, Sohn, Jongsu
Vacuum structure and global cosmic strings are analyzed in the effective theory of self-interacting O(2) scalar fields on (3+1)-manifolds with conical singularities. In the context of one-loop...
PP-wave/Yang-Mills Correspondence: An Explicit Check (2002)
Kiem, Youngjai, Kim, Yoonbai, Lee, Sangmin, Park, Jaemo
We present an explicit evidence that shows the correspondence between the type IIB supergravity in the pp-wave background and its dual supersymmetric Yang-Mills theory at the interaction level. We...
First and Second Order Vortex Dynamics (2002)
The low energy dynamics of vortices in selfdual Abelian Higgs theory is of second order in vortex velocity and characterized by the moduli space metric. When Chern-Simons term with small coefficient...
Path integral formulation of Hodge duality on the brane (2001)
Hahn, Sang-Ok, Kiem, Youngjai, Kim, Yoonbai, Oh, Phillial
In the warped compactification with a single Randall-Sundrum brane, a puzzling claim has been made that scalar fields can be bound to the brane but their Hodge dual higher-rank anti-symmetric tensors...
Kiem, Youngjai, Kim, Chanju, Kim, Yoonbai
We obtain Q-ball solutions in noncommutative scalar field theory with a global U(1) invariance. The Q-ball solutions are shown to be classically and quantum mechanically stable. We also find that...
Gravitating Self-dual Chern-Simons Solitons (2001)
Chung, Bok Keun, Chung, Jin-Mo, Kim, Seongtag, Kim, Yoonbai
Self-dual solitons of Chern-Simons Higgs theory are examined in curved spacetime. We derive duality transformation of the Einstein Chern-Simons Higgs theory within path integral formalism and study...
Self-dual Chern-Simons Vortices on Riemann Surfaces (2000)
We study self-dual multi-vortex solutions of Chern-Simons Higgs theory in a background curved spacetime. The existence and decaying property of a solution are demonstrated.
Kim, Yoonbai, Lee, Seung Joo, Maeda, Kei-ichi, Sakai, Nobuyuki
The decay of a metastable false vacuum by bubble nucleation is studied in the high temperature limit of the gauge theory in which an SO(3) gauge symmetry is spontaneously broken to an SO(2). The...
Black Hole Entropy and Exclusion Statistics (1998)
Kim, Hyeong-Chan, Kim, Yoonbai, Oh, Phillial
We compute the entropy of systems of quantum particles satisfying the fractional exclusion statistics in the space-time of 2+1 dimensional black hole by using the brick-wall method. We show that the...
Gravitating $\sigma$ Model Solitons (1998)
We study axially symmetric static solitons of O(3) nonlinear $\sigma$ model coupled to (2+1)-dimensional anti-de Sitter gravity. The obtained solutions are not self-dual under static metric. The...
Bogomolnyi Bound with a Cosmological Constant (1998)
Bogomolnyi-type bound is constructed for the topological solitons in O(3) nonlinear $\sigma$ model coupled to gravity with a negative cosmological constant. Spacetimes made by self-dual solutions...
Thirring Model in Lower Dimensions: Nonperturbative Approaches (1997)
A reformulation of the Thirring model as a gauge theory on both continuum spacetime and discretized lattice is reviewed. In (1+1) dimensions, our result reproduces consistently the bosonization of...
Global Vortex and Black Cosmic String (1997)
Kim, Nakwoo, Kim, Yoonbai, Kimm, Kyoungtae
We study global vortices coupled to (2+1) dimensional gravity with negative cosmological constant. We found nonsingular vortex solutions in $\phi^4$-theory with a broken U(1) symmetry, of which the...
Charged Black Cosmic String (1997)
Kim, Nakwoo, Kim, Yoonbai, Kimm, Kyoungtae
Global U(1) strings with cylindrical symmetry are studied in anti-de Sitter spacetime. According as the magnitude of negative cosmological constant, they form regular global cosmic strings, extremal...
Self-dual Chern-Simons Solitons in the Planar Ferromagnet (1997)
Kim, Yoonbai, Oh, Phillial, Rim, Chaiho
We consider a uniaxial planar ferromagnet coupled minimally to an Abelian Chern-Simons gauge field and study self-dual solitons which saturate the Bogomol'nyi bound. We find a rich structure of...
Production of Global Monopoles through the Nucleation of $O(3)$ Bubbles (1996)
Kim, Yoonbai, Maeda, Kei-ichi, Sakai, Nobuyuki
First-order cosmological phase transitions are considered in the models with an $O(3)$-symmetric scalar field, in the high temperature limit. It is shown that a global monopole can be produced at the...
Dynamical Symmetry Breaking in a Gauge Theory ``Thirring Model'' (1996)
Itoh, Taichi, Kim, Yoonbai, Sugiura, Masaki, Yamawaki, Koichi
Dynamical fermion mass generation is studied in the three-dimensional Thirring model reformulated as a gauge theory by introducing hidden local symmetry. The analysis by use of Schwinger-Dyson...
Lattice Gauge Theory of Three Dimensional Thirring Model (1996)
Three dimensional Thirring model with $N$ four-component Dirac fermions, reformulated as a lattice gauge theory, is studied by computer simulation. According to an $8^{3}$ data and preliminary $16^3$...
Monopole-Bubble in Early Universe (1996)
Kim, Yoonbai, Maeda, Kei-ichi, Sakai, Nobuyuki
The nucleation and evolution of bubbles are investigated in the model of an $O(3)$-symmetric scalar field coupled to gravity in the high temperature limit. It is shown that, in addition to the...
Solitonic Island in the Bubble (1996)
Kim, Yoonbai, Maeda, Kei-ichi, Sakai, Nobuyuki
We review how the continuous symmetry can support a soliton inside a high-temperature bubble at the time of its nucleation. This solitonic island in disoriented phase remains stable during the growth...
Bubbles with an O(3) Symmetric Scalar Field in Curved Spacetime (1995)
Sakai, Nobuyuki, Kim, Yoonbai, Maeda, Kei-ichi
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...
NAMBU-GOLDSTONE BOSON ON THE LIGHT-FRONT (1995)
Kim, Yoonbai, Tsujimaru, Sho, Yamawaki, Koichi
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...
Can the Nambu-Goldstone Boson Live on the Light-Front? (1995)
Kim, Yoonbai, Tsujimaru, Sho, Yamawaki, Koichi
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 $m_{\pi}$. The NG-boson zero...
Thirring Model as a Gauge Theory (1994)
Itoh, Taichi, Kim, Yoonbai, Sugiura, Masaki, Yamawaki, Koichi
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...
Comment on "Obstructions to the Existence of Static Cosmic Strings in an Abelian Higgs Model" (1994)
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...
Bubble with Global Monopole (1994)
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...
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...
Vortex Dynamics in Self-Dual Chern-Simons Higgs Systems (1992)
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...
Two views of the real exchange rate in international adjustment / (1986)
Thesis (Ph. D.)--Stanford University, 1987.
The Empirical Relationship Between Exchange Rates and Interest Rates in Post-Crisis Asia
In post-crisis Asia, all crisis-hit countries (except Malaysia) announced a shift from exchange rate based monetary policy framework to the explicit adoption of inflation targeting that uses interest...
This article estimates the import-price function in the United States using a varying-parameter model. The results show that the short-run nonoil import-price changes have become relatively less...
HOW REAL ARE REAL EXCHANGE RATES?
This paper analyzes the role of real disturbances in the real dollar exchange rates of the mark, yen and the pound both during the post-1973 float and in the long-run historical data. The results...
Purchasing Power Parity in the Long Run: A Cointegration Approach.
This paper utilizes cointegration analysis to examine purchasing power parity relationships over a long-time horizon. The results indicate that the exchange rate is cointegrated strongly with the...
Income Effects on the Trade Balance.
This paper investigates the income effects on the trade balance with particular attention to the distinction between permanent and transitory disturbances for the United States, Japan, Germany, and...
External Adjustments and Exchange Rate Flexibility: Some Evidence from U.S. Data.
This paper examines the role of the exchange rate in U.S. external adjustments. The results show that the exchange rate is an important transmission channel of influence on prices, and with longer...
Is the Chinese Renminbi Undervalued?
This article seeks to investigate whether the renminbi (RMB) has become grossly undervalued by empirically estimating China's equilibrium real exchange rate for the period 1978--2002. A reduced form...
Trade balance and income in historical perspective
This paper develops a dynamic analysis of the trade balance to investigate the roles of supply and demand shocks. It also introduces global shocks in the analysis to take into account the comovement...
An Empirical Analysis on Capital Flows: The Case of Korea and Mexico
This paper discusses causes of capital flows in Korea and Mexico. Both countries received substantial amounts of foreign capital in the late 1980s and early 1990s. International capital helped these...
IS THE CHINESE RENMINBI UNDERVALUED?
This article seeks to investigate whether the renminbi (RMB) has become grossly undervalued by empirically estimating China's equilibrium real exchange rate for the period 1978-2002. A reduced form...
Economics and politics in the United States: a state-level investigation
Chun-Ping Chang, Yoonbai Kim, Yung-hsiang Ying
We examine state income and government spending data to investigate the role of political parties and elections in state business cycles of the United States, and find strong support for the partisan...