Non-Abelian Global Strings at Chiral Phase Transition

We construct non-Abelian global string solutions in the U(N)_L x U(N)_R linear sigma model. These strings are the most fundamental objects which are expected to form during the chiral phase transitions, because the Abelian eta' string is marginally decomposed into N of them. We point out Nambu-Goldstone modes of CP^{N-1} for breaking of U(N)_V arise around a non-Abelian vortex.Comment: 10 pages, 2 figure

Non-Abelian Walls in Supersymmetric Gauge Theories

The Bogomol'nyi-Prasad-Sommerfield (BPS) multi-wall solutions are constructed in supersymmetric U(N_C) gauge theories in five dimensions with N_F(>N_C) hypermultiplets in the fundamental representation. Exact solutions are obtained with full generic moduli for infinite gauge coupling and with partial moduli for finite gauge coupling. The generic wall solutions require nontrivial configurations for either gauge fields or off-diagonal components of adjoint scalars depending on the gauge. Effective theories of moduli fields are constructed as world-volume gauge theories. Nambu-Goldstone and quasi-Nambu-Goldstone scalars are distinguished and worked out. Total moduli space of the BPS non-Abelian walls including all topological sectors is found to be the complex Grassmann manifold SU(N_F) / [SU(N_C) x SU(N_F-N_C) x U(1)] endowed with a deformed metric.Comment: 62 pages, 17 figures, the final version in PR

Non-integrability of Self-dual Yang-Mills-Higgs System

We examine integrability of self-dual Yang-Mills system in the Higgs phase, with taking simpler cases of vortices and domain walls. We show that the vortex equations and the domain-wall equations do not have Painleve property. This fact suggests that these equations are not integrable.Comment: 15 pages, no figures, v2: references added, v3: typos corrected, the final version to appear in NP

Stable vs Unstable Vortices in SQCD

We give a topological classification of stable and unconfined massive particles and strings (and some instantons) in worldvolume theories of M5-branes and their dimensional reductions, generalizing Witten's classification of strings in SYM. In particular 4d N=2 SQCD softly broken to N=1 contains torsion (Douglas-Shenker) Z_N-strings and nontorsion (Hanany-Tong) Z-strings. Some of the former are stable when the flavor symmetry is gauged, while those that are not stable confine quarks and in some vacua even dyons into baryons. The nontorsion strings are stable if and only if all colors are locked to flavors, which is weaker than the BPS condition. As a byproduct unstable string decay modes and approximate lifetimes are found. Cascading theories have no vortices stabilized by the topological charges treated here and in particular Gubser-Herzog-Klebanov axionic strings do not carry such a charge.Comment: 32 pages, 6 figure