2,204 research outputs found
Revisiting Critical Vortices in Three-Dimensional SQED
We consider renormalization of the central charge and the mass of the supersymmetric Abelian vortices in 2+1 dimensions. We obtain
supersymmetric theory in 2+1 dimensions by dimensionally reducing the SQED in 3+1 dimensions with two chiral fields carrying opposite charges.
Then we introduce a mass for one of the matter multiplets without breaking N=2
supersymmetry. This massive multiplet is viewed as a regulator in the large
mass limit. We show that the mass and the central charge of the vortex get the
same nonvanishing quantum corrections, which preserves BPS saturation at the
quantum level. Comparison with the operator form of the central extension
exhibits fractionalization of a global U(1) charge; it becomes 1/2 for the
minimal vortex. The very fact of the mass and charge renormalization is due to
a "reflection" of an unbalanced number of the fermion and boson zero modes on
the vortex in the regulator sector.Comment: 24 pages, 2 figures Minor modifications, reference adde
Large-N Solution of the Heterotic CP(N-1) Model with Twisted Masses
We address a number of unanswered questions in the N=(0,2)-deformed CP(N-1)
model with twisted masses. In particular, we complete the program of solving
CP(N-1) model with twisted masses in the large-N limit. In hep-th/0512153
nonsupersymmetric version of the model with the Z_N symmetric twisted masses
was analyzed in the framework of Witten's method. In arXiv:0803.0698 this
analysis was extended: the large-N solution of the heterotic N=(0,2) CP(N-1)
model with no twisted masses was found. Here we solve this model with the
twisted masses switched on. Dynamical scenarios at large and small m are
studied (m is the twisted mass scale). We found three distinct phases and two
phase transitions on the m plane. Two phases with the spontaneously broken
Z_N-symmetry are separated by a phase with unbroken Z_N. This latter phase is
characterized by a unique vacuum and confinement of all U(1) charged fields
("quarks"). In the broken phases (one of them is at strong coupling) there are
N degenerate vacua and no confinement, similarly to the situation in the
N=(2,2) model. Supersymmetry is spontaneously broken everywhere except a circle
|m|=\Lambda in the Z_N-unbroken phase. Related issues are considered. In
particular, we discuss the mirror representation for the heterotic model in a
certain limiting case.Comment: 69 pages, 14 figures; typos corrected, final version to appear in
PRD; v Jan. 2014 Erratum added on p. 50, two references added and two
references update
Higher Winding Strings and Confined Monopoles in N=2 SQCD
We consider composite string solutions in N=2 SQCD with the gauge group U(N),
the Fayet--Iliopoulos term \xi \neq 0 and N (s)quark flavors. These bulk
theories support non-Abelian strings and confined monopoles identified with
kinks in the two-dimensional world-sheet theory. Similar and more complicated
kinks (corresponding to composite confined monopoles) must exist in the
world-sheet theories on composite strings. In a bid to detect them we analyze
the Hanany--Tong (HT) model, focusing on a particular example of N=2. Unequal
quark mass terms in the bulk theory result in the twisted masses in the N=(2,2)
HT model. For spatially coinciding 2-strings, we find three distinct minima of
potential energy, corresponding to three different 2-strings. Then we find
BPS-saturated kinks interpolating between each pair of vacua. Two kinks can be
called elementary. They emanate one unit of the magnetic flux and have the same
mass as the conventional 't Hooft--Polyakov monopole on the Coulomb branch of
the bulk theory (\xi =0). The third kink represents a composite bimonopole,
with twice the minimal magnetic flux. Its mass is twice the mass of the
elementary confined monopole. We find instantons in the HT model, and discuss
quantum effects in composite strings at strong coupling. In addition, we study
the renormalization group flow in this model.Comment: 41 pages, 11 figure
Quantum Fusion of Domain Walls with Fluxes
We study how fluxes on the domain wall world volume modify quantum fusion of
two distant parallel domain walls into a composite wall. The elementary wall
fluxes can be separated into parallel and antiparallel components. The parallel
component affects neither the binding energy nor the process of quantum merger.
The antiparallel fluxes, instead, increase the binding energy and, against
naive expectations, suppress quantum fusion. In the small flux limit we
explicitly find the bounce solution and the fusion rate as a function of the
flux. We argue that at large (antiparallel) fluxes there exists a critical
value of the flux (versus the difference in the wall tensions), which switches
off quantum fusion altogether. This phenomenon of flux-related wall
stabilization is rather peculiar: it is unrelated to any conserved quantity.
Our consideration of the flux-related all stabilization is based on
substantiated arguments that fall short of complete proof.Comment: 17 pages, 3 figure
Relaxing a constraint on the number of messengers in a low-scale gauge mediation
We propose a mechanism for relaxing a constraint on the number of messengers
in low-scale gauge mediation models. The Landau pole problem for the
standard-model gauge coupling constants in the low-scale gauge mediation can be
circumvented by using our mechanism. An essential ingredient is a large
positive anomalous dimension of messenger fields given by a large Yukawa
coupling in a conformal field theory at high energies. The positive anomalous
dimension reduces the contribution of the messengers to the beta function of
the standard-model gauge couplings.Comment: 22pages; v2:explanations expanded in sec.3.2, reference adde
Confinement and Localization on Domain Walls
We continue the studies of localization of the U(1) gauge fields on domain
walls. Depending on dynamics of the bulk theory the gauge field localized on
the domain wall can be either in the Coulomb phase or squeezed into flux tubes
implying (Abelian) confinement of probe charges on the wall along the wall
surface. First, we consider a simple toy model with one flavor in the bulk at
weak coupling (a minimal model) realizing the latter scenario. We then suggest
a model presenting an extension of the Seiberg--Witten theory which is at
strong coupling, but all theoretical constructions are under full control if we
base our analysis on a dual effective action. Finally, we compare our findings
with the wall in a "nonminimal" theory with two distinct quark flavors that had
been studied previously. In this case the U(1) gauge field trapped on the wall
is exactly massless because it is the Goldstone boson of a U(1) symmetry in the
bulk spontaneously broken on the wall. The theory on the wall is in the Coulomb
phase. We explain why the mechanism of confinement discussed in the first part
of the paper does not work in this case, and strings are not formed on the
walls.Comment: 55 pp; v2: several remarks adde
QSSR estimate of the parameter at next-to-leading order
We compute the leading corrections to the two-point correlator of
the operator which controls the mixing. Using
this result within the QCD spectral sum rules approach and some
phenomenologically reasonable assumptions in the parametrization of the
spectral function, we conclude that the vacuum saturation values are satisfied within 15\%.Comment: 8 pages, LaTeX, CERN-TH.7140/94, PM 93/16, and KEK Preprint 93-184,
two figures appended as a PS fil
Central Charge Anomalies in 2D Sigma Models with Twisted Mass
We discuss the central charge in supersymmetric sigma models in
two dimensions. The target space is a symmetric K\"ahler manifold, CP is
an example. The U(1) isometries allow one to introduce twisted masses in the
model. At the classical level the central charge contains Noether charges of
the U(1) isometries and a topological charge which is an integral of a total
derivative of the Killing potentials. At the quantum level the topological part
of the central charge acquires anomalous terms. A bifermion term was found
previously, using supersymmetry which relates it to the superconformal anomaly.
We present a direct calculation of this term using a number of regularizations.
We derive, for the first time, the bosonic part in the central charge anomaly.
We construct the supermultiplet of all anomalies and present its superfield
description. We also discuss a related issue of BPS solitons in the CP(1) model
and present an explicit form for the curve of marginal stability.Comment: 30 pages, 1 figure, references adde
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