768 research outputs found
The Vacuum Structure of N=2 SuperQCD with Classical Gauge Groups
We determine the vacuum structure of N=2 supersymmetric QCD with fundamental
quarks for gauge groups SO(n) and Sp(2n), extending prior results for SU(n).
The solutions are all given in terms of families of hyperelliptic Riemann
surfaces of genus equal to the rank of the gauge group. In the scale invariant
cases, the solutions all have exact S-dualities which act on the couplings by
subgroups of PSL(2,Z) and on the masses by outer automorphisms of the flavor
symmetry. They are shown to reproduce the complete pattern of symmetry breaking
on the Coulomb branch and predict the correct weak--coupling monodromies.
Simple breakings with squark vevs provide further consistency checks involving
strong--coupling physics.Comment: 29 pages, harvmac, 1 figure included using epsf.te
A Search for Non-Perturbative Dualities of Local Yang--Mills Theories from Calabi--Yau Threefolds
The generalisation of the rigid special geometry of the vector multiplet
quantum moduli space to the case of supergravity is discussed through the
notion of a dynamical Calabi--Yau threefold. Duality symmetries of this
manifold are connected with the analogous dualities associated with the
dynamical Riemann surface of the rigid theory. N=2 rigid gauge theories are
reviewed in a framework ready for comparison with the local case. As a
byproduct we give in general the full duality group (quantum monodromy) for an
arbitrary rigid gauge theory, extending previous explicit
constructions for the cases. In the coupling to gravity, R--symmetry
and monodromy groups of the dynamical Riemann surface, whose structure we
discuss in detail, are embedded into the symplectic duality group
associated with the moduli space of the dynamical Calabi--Yau threefold.Comment: Latex. Version of previous paper with enlarged and revised appendix
35 pages, plain LaTe
Nonperturbative Relations in N=2 SUSY Yang-Mills and WDVV equation
We find the nonperturbative relation between , the prepotential and the
vevs in supersymmetric Yang-Mills theories with
gauge group . Nonlinear differential equations for including
the Witten -- Dijkgraaf -- Verlinde -- Verlinde equation are obtained. This
indicates that SYM theories are essentially topological field theories
and that should be seen as low-energy limit of some topological string theory.
Furthermore, we construct relevant modular invariant quantities, derive
canonical relations between the periods and investigate the structure of the
beta function by giving its explicit form in the moduli coordinates. In doing
this we discuss the uniformization problem for the quantum moduli space. The
method we propose can be generalized to supersymmetric Yang-Mills
theories with higher rank gauge groups.Comment: 12 pages, LaTex. Expanded version. New results, corrections,
references and acknowledgements adde
The Moduli Space of N=2 SUSY QCD and Duality in N=1 SUSY QCD
We analyze in detail the moduli space of vacua of N=2 SUSY QCD with n_c
colors and n_f flavors. The Coulomb branch has submanifolds with non-Abelian
gauge symmetry. The massless quarks and gluons at these vacua are smoothly
connected to the underlying elementary quarks and gluons. Upon breaking N=2 by
an N=1 preserving mass term for the adjoint field the theory flows to N=1 SUSY
QCD. Some of the massless quarks and gluons on the moduli space of the N=2
theory become the magnetic quarks and gluons of the N=1 theory. In this way we
derive the duality in N=1 SUSY QCD by identifying its crucial building
blocks---the magnetic degrees of freedom---using only semiclassical physics and
the non-renormalization theorem.Comment: 46 pages harvmac, 3 figures included using epsf.te
Stable de Sitter vacua in N=2, D=5 supergravity
We find 5D gauged supergravity theories exhibiting stable de Sitter vacua.
These are the first examples of stable de Sitter vacua in higher-dimensional
(D>4) supergravity. Non-compact gaugings with tensor multiplets and R-symmetry
gauging seem to be the essential ingredients in these models. They are however
not sufficient to guarantee stable de Sitter vacua, as we show by investigating
several other models. The qualitative behaviour of the potential also seems to
depend crucially on the geometry of the scalar manifold.Comment: 26 pages, v2:typos corrected, published versio
Geometric Transition as a Change of Polarization
Taking the results of hep-th/0702110 we study the Dijkgraaf-Vafa open/closed
topological string duality by considering the wavefunction behavior of the
partition function. We find that the geometric transition associated with the
duality can be seen as a change of polarization.Comment: 20 page
Plasma Resonance in Layered Normal Metals and Superconductors
A microscopic theory of the plasma resonance in layered metals is presented.
It is shown that electron-impurity scattering can suppress the plasma resonance
in the normal state and sharpen it in the superconducting state. Analytic
properties of the conductivity for the electronic transport perpendicular to
the layers are investigated. The dissipative part of the electromagnetic
response in c-direction has been found to depend on frequency in a highly
non-trivial manner. This sort of behavior cannot be incorporated in the widely
used phenomenological Gorter-Kazimir model.Comment: 34 pages including 12 figures in uuencoded.file. A revised version.
Several formulas and a number of misprints are corrected. A problem with
printing of figures is fixe
Phase-change meta-photonics
We combine phase-change materials and metamaterial arrays (metasurfaces) to create new forms of dynamic, tuneable and reconfigurable photonic devices including âperfectâ absorbers, infra-red light modulators, optical beam steerers and enhanced phase-change optoelectronic displays
The M5-Brane Elliptic Genus: Modularity and BPS States
The modified elliptic genus for an M5-brane wrapped on a four-cycle of a
Calabi-Yau threefold encodes the degeneracies of an infinite set of BPS states
in four dimensions. By holomorphy and modular invariance, it can be determined
completely from the knowledge of a finite set of such BPS states. We show the
feasibility of such a computation and determine the exact modified elliptic
genus for an M5-brane wrapping a hyperplane section of the quintic threefold.Comment: 21 page
w_{\infty} Algebras, Conformal Mechanics, and Black Holes
We discuss BPS solitons in gauged , D=4 supergravity. The
solitons represent extremal black holes interpolating between different vacua
of anti-de Sitter spaces. The isometry superalgebras are determined and the
motion of a superparticle in the extremal black hole background is studied and
confronted with superconformal mechanics. We show that the Virasoro symmetry of
conformal mechanics, which describes the dynamics of the superparticle near the
horizon of the extremal black hole under consideration, extends to a symmetry
under the algebra of area-preserving diffeomorphisms. We find that
a Virasoro subalgebra of can be associated to the Virasoro algebra
of the asymptotic symmetries of . In this way spacetime diffeomorphisms
of translate into diffeomorphisms in phase space: our system offers an
explicit realization of the correspondence. Using the
dimensionally reduced action, the central charge is computed. Finally, we also
present generalizations of superconformal mechanics which are invariant under
and superextensions of .Comment: Latex, 23 pages, minor errors corrected, references added; final
version to appear in Class. Quant. Gra
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