Taejin Lee

The Chern-Simons coefficient in supersymmetric Yang-Mills Chern-Simons theories

Abstract We study one-loop corrections to the Chern-Simons coefficient κ = k 4π in N = 1, 2, 3 supersymmetric Yang-Mills Chern-Simons systems. In the pure bosonic case, the shift of the parameter k is known to be k → k + cv, where cv is the quadratic Casimir of the gauge group. In the N = 1 case, the fermionic contribution cancels the bosonic contribution by half and the shift is k → k + c v 2 , making the theory anomalous if cv is odd. In the N = 2, 3 cases, the fermionic contribution cancels the bosonic contribution completely and there is no correction. We also calculate the mass corrections, and show that the supersymmetry is preserved. As the matter fields decouple from the gauge field in the pure Chern-Simons limit, this work sheds some light on the regularization dependency of the correction in pure Chern-Simons systems. We also discuss the implication to the case when the gauge symmetry is spontaneously broken by the Higgs mechanism.

Canonical quantization of open string and noncommutative geometry

We perform canonical quantization of open strings in the

Anyonic Bogomol'nyi solitons in a gauged O(3) sigma model.

D

Tachyon condensation, boundary state and noncommutative solitons

-brane background with a

Noncommutative Dirac–Born–Infeld action for D-brane

B

The self-dual Chern-Simons CP(N) models

-field. Treating the mixed boundary condition as a primary constraint, we get a set of secondary constraints. Then these constraints are shown to be equivalent to orbifold conditions to be imposed on normal string modes. These orbifold conditions are a generalization of the familiar orbifold conditions which arise when we describe open strings in terms of closed strings. Solving the constraints explicitly, we obtain a simple Hamiltonian for the open string, which reveals the nature of noncommutativity transparently.

Tachyon condensation and open string field theory

We introduce the self-dual abelian gauged

Two dimensional anti-de Sitter space and discrete light cone quantization

O(3)

BPS domain wall solutions in self-dual Chern-Simons-Higgs systems

sigma models where the Maxwell and Chern-Simons terms constitute the kinetic terms for the gauge field. These models have quite rich structures and various limits. Our models are found to exhibit both symmetric and broken phases of the gauge group. We discuss the pure Chern-Simons limit in some detail and study rotationally symmetric solitons.

Coherent state quantization of SU(N) non-Abelian Chern-Simons particles

We discuss tachyon condensation in a single unstable D-brane in the framework of the boundary state formulation. The boundary state in the background of tachyon condensation and the Neveu-Schwarz B-field is explicitly constructed. We show in both commutative theory and noncommutative theory that the unstable D-branes behave like an extended object and eventually reduce to lower dimensional D-branes as the system approaches the infrared fixed point. We clarify the relationship between the commutative field theoretical description of tachyon condensation and the noncommutative one.