9,070 research outputs found
Moduli Space Potentials for Heterotic non-Abelian Flux Tubes: Weak Deformation
We consider N=2 supersymmetric QCD with the U(N) gauge group (with no
Fayet-Iliopoulos term) and N_f flavors of massive quarks deformed by the mass
term \mu for the adjoint matter, W=\mu A^2, assuming that N\leq N_f<2N. This
deformation breaks N=2 supersymmetry down to N=1. This theory supports
non-Abelian flux tubes (strings) which are stabilized by W. They are referred
to as F-term stabilized strings. We focus on the studies of such strings in the
vacuum in which N squarks condense, at small \mu, so that the Z_N strings
preserve, in a sense, their BPS nature. We calculate string tensions both in
the classical and quantum regimes. Then we translate our results for the
tensions in terms of the effective low-energy weighted CP(N_f-1) model on the
string world sheet. The bulk \mu-deformation makes this theory N= (0,2)
supersymmetric heterotic weighted CP(N_f-1) model in two dimensions. We find
the deformation potential on the world sheet. This significantly expands the
class of the heterotically deformed CP models emerging on the string world
sheet compared to that suggested by Edalati and Tong. Among other things, we
show that nonperturbative quantum effects in the bulk theory are exactly
reproduced by the quantum effects in the world-sheet theory.Comment: 39 pages, 1 fig; v2: 1 reference added, two explanatory remarks
added; Final version, to appear in PR
Non-Abelian Strings: From Weak to Strong Coupling and Back via Duality
The crossover transition from weak coupling at large \xi to strong coupling
at small \xi is studied in N=2 supersymmetric gauge theory with the U(N) gauge
group and N_f>N (here \xi is the Fayet--Iliopoulos parameter). We find that at
strong coupling a dual non-Abelian weakly coupled N=2 theory exists which
describes low-energy physics at small \xi. The dual gauge group is U(N_f-N).
The dual theory has N_f flavors of light dyons, to be compared with N_f quarks
in the original U(N) theory. Both theories support non-Abelian strings. In each
of these two regimes there are two varieties of physical excitations:
elementary fields and nonperturbative composite states bound by confining
strings. These varieties interchange upon transition from one regime to the
other. We conjecture that the composite stringy states can be related to
Seiberg's M fields.Comment: Plenary talk at SUSY09: 17th International Conference on
Supersymmetry and the Unification of Fundamental Interactions, Northeastern
Univ. Boston, 5-10 June, 200
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