658 research outputs found
Monopoles Can be Confined by 0, 1 or 2 Vortices
There are three types of monopole in gauge theories with fundamental matter
and N=2 supersymmetry broken by a superpotential. There are unconfined
0-monopoles and also 1 and 2-monopoles confined respectively by one or two
vortices transforming under distinct components of the unbroken gauge group. If
a Fayet-Iliopoulos term is added then there are only 2-monopoles. Monopoles
transform in the bifundamental representation of two components of the unbroken
gauge symmetry, and if two monopoles share a component they may form a
boundstate. Selection rules for this process are found, for example vortex
number is preserved modulo 2. We find the tensions of the vortices, which are
in general distinct, and also the conditions under which vortices are mutually
BPS. Results are derived in field theory and also in MQCD, and in quiver
theories a T-dual picture may be used in which monopoles are classified by
quiver diagrams with two colors of vertices.Comment: 46 pages, 13 figures, V2: Comment on non-BPS correction added; 1
figure adde
NonAbelian Vortices, Large Winding Limits and Aharonov-Bohm Effects
Remarkable simplification arises from considering vortex equations in the
large winding limit. This was recently used in [1] to display all sorts of
vortex zeromodes, the orientational, translational, fermionic as well as
semi-local, and to relate them to the apparently distinct phenomena of the
Nielsen-Olesen-Ambjorn magnetic instabilities. Here we extend these analyses to
more general types of BPS nonAbelian vortices, taking as a prototype a system
with gauged U(1) x SU(N) x SU(N) symmetry where the VEV of charged scalar
fields in the bifundamental representation breaks the symmetry to SU(N)_{l+r} .
The presence of the massless SU(N)_{l+r} gauge fields in 4D bulk introduces all
sorts of non-local, topological phenomena such as the nonAbelian Aharonov-Bohm
effects, which in the theory with global SU(N)_r group (g_r=0) are washed away
by the strongly fluctuating orientational zeromodes in the worldsheet. Physics
changes qualitatively at the moment the right gauge coupling constant g_r is
turned on.Comment: 31 pages, 4 figure
A Coincidence Problem: How to Flow from N=2 SQCD to N=1 SQCD
We discuss, and propose a solution for, a still unresolved problem regarding
the breaking from super-QCD to super-QCD. A mass term W=\mu \Tr
\Phi^2 / 2 for the adjoint field, which classically does the required breaking
perfectly, quantum mechanically leads to a relevant operator that, in the
infrared, makes the theory flow away from pure SQCD. To avoid this
problem, we first need to extend the theory from \SU (n_c) to \U (n_c). We
then look for the quantum generalization of the condition ,
that is, the coincidence between a root of the derivative of the superpotential
and the mass of the quarks. There are of such points
in the moduli space. We suggest that with an opportune choice of
superpotential, that selects one of these coincidence vacua in the moduli
space, it is possible to flow from SQCD to SQCD. Various
arguments support this claim. In particular, we shall determine the exact
location in the moduli space of these coincidence vacua and the precise
factorization of the SW curve.Comment: 45 pp. v2: typos corrected. v3,v4: other minor correction
Large N, Z_N Strings and Bag Models
We study Z_N strings in nonabelian gauge theories, when they can be
considered as domain walls compactified on a cylinder and stabilized by the
flux inside. To make the wall vortex approximation reliable, we must take the
't Hooft large N limit. Our construction has many points in common with the
phenomenological bag models of hadrons.Comment: 24 pages, 5 figures. v2: Corrected a 1/N factor in the large N QCD
sectio
On Some Universal Features of the Holographic Quantum Complexity of Bulk Singularities
We perform a comparative study of the time dependence of the holographic
quantum complexity of some space like singular bulk gravitational backgrounds.
This is done by considering the two available notions of complexity, one that
relates it to the maximal spatial volume and the other that relates it to the
classical action of the Wheeler-de Witt patch. We calculate and compare the
leading and the next to leading terms and find some universal features. The
complexity decreases towards the singularity for both definitions, for all
types of singularities studied. In addition the leading terms have the same
quantitative behavior for both definitions in restricted number of cases and
the behaviour itself is different for different singular backgrounds. The
quantitative details of the next to leading terms, such as their specific form
of time dependence, are found not to be universal. They vary between the
different cases and between the different bulk definitions of complexity. We
also address some technical points inherent to the calculation.Comment: 24 pages, 6 figures. v2: minor correction
Holographic Dual of the Lowest Landau Level
We describe the lowest Landau level of a quantum electron star in AdS4. In
the presence of a suitably strong magnetic field, the dynamics of fermions in
the bulk is effectively reduced from four to two dimensions. These
two-dimensional fermions can subsequently be treated using the techniques of
bosonization and the difficult many-body problem of building a gravitating,
charged quantum star is reduced to solving the sine-Gordon model coupled to a
gauge field and a metric. The kinks of the sine-Gordon model provide the
holographic dual of the lowest Landau levels of the strongly-coupled d=2+1
dimensional boundary field theory. The system exhibits order one oscillations
in the magnetic susceptibility, now arising as a classical effect in the bulk.
Moreover, as the chemical potential is varied, we find jumps in the charge
density, oscillations in the fractionalised charge density and plateaux in the
cohesive charge densityComment: 39 pages; 8 Figure
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