2,360 research outputs found
Elliptic supertube and a Bogomol'nyi-Prasad-Sommerfield D2-brane--anti-D2-brane Pair
An exact solution, in which a D2-brane and an anti-D2-brane are connected by
an elliptically tubular D2-brane, is obtained without any junction condition.
The solution is shown to preserve one quarter of the supersymmetries of the
type-IIA Minkowski vacuum. We show that the configuration cannot be obtained by
"blowing-up" from some inhomogeneously D0-charged superstrings. The BPS bound
tells us that it is rather composed of D0-charged D2-brane-anti-D2-brane pair
and a strip of superstrings connecting them. We obtain the correction to the
charges of the string end points in the constant magnetic background.Comment: v3. 12 pages, journal version; title changed, length trimmed to fit
for Rapid Communication forma
Radiation Damping of a BPS Monopole; an Implication to S-duality
The radiation reaction of a BPS monopole in the presence of incident
electromagnetic waves as well as massless Higgs waves is analyzed classically.
The reactive forces are compared to those of boson that is interpreted as a
dual partner of the BPS monopole. It is shown that the damping of acceleration
is dual to each other, while in the case of finite size effects the duality is
broken explicitly. Their implications on the duality are discussed.Comment: 20 pages, uses revtex, changes in reference
Complete Supersymmetric Quantum Mechanics of Magnetic Monopoles in N=4 SYM Theory
We find the most general low energy dynamics of 1/2 BPS monopoles in the N=4
supersymmetric Yang-Mills theories (SYM) when all six adjoint Higgs expectation
values are turned on. When only one Higgs is turned on, the Lagrangian is
purely kinetic. When all six are turned on, however, this moduli space dynamics
is augmented by five independent potential terms, each in the form of half the
squared norm of a Killing vector field on the moduli space. A generic
stationary configuration of the monopoles can be interpreted as stable non BPS
dyons, previously found as non-planar string webs connecting D3-branes. The
supersymmetric extension is also found explicitly, and gives the complete
quantum mechanics of monopoles in N=4 SYM theory. We explore its supersymmetry
algebra.Comment: Errors in the SUSY algebra corrected. The version to appear in PR
Layer Features of the Lattice Gas Model for Self-Organized Criticality
A layer-by-layer description of the asymmetric lattice gas model for
1/f-noise suggested by Jensen [Phys. Rev. Lett. 64, 3103 (1990)] is presented.
The power spectra of the lattice layers in the direction perpendicular to the
particle flux is studied in order to understand how the white noise at the
input boundary evolves, on the average, into 1/f-noise for the system. The
effects of high boundary drive and uniform driving force on the power spectrum
of the total number of diffusing particles are considered. In the case of
nearest-neighbor particle interactions, high statistics simulation results show
that the power spectra of single lattice layers are characterized by different
exponents such that as one approaches the outer
boundary.Comment: LaTeX, figures upon reques
Exact 4-point Scattering Amplitude of the Superconformal Schrodinger Chern-Simons Theory
We consider the non-relativistic superconformal U(N) X U(N) Chern-Simons
theory with level (k,-k) possessing fourteen supersymmetries. We obtain an
exact four-point scattering amplitude of the theory to all orders in 1/N and
1/k and prove that the scattering amplitude becomes trivial when k=1 and 2. We
confirm this amplitude to one-loop order by using an explicit field theoretic
computation and show that the beta function for the contact interaction
vanishes to the one-loop order, which is consistent with the quantum conformal
invariance of the underlying theory.Comment: 16 page
Dynamics of BPS Dyons: Effective Field Theory Approach
Based on a detailed analysis of nonlinear field equations of the SU(2)
Yang-Mills-Higgs system, we obtain the effective field theory describing
low-energy interaction of BPS dyons and massless particles (i.e., photons and
Higgs particles). Our effective theory manifests electromagnetic duality and
spontaneously broken scale symmetry, and reproduces the multimonopole moduli
space dynamics of Manton in a suitable limit. Also given is a generalization of
our approach to the case of BPS dyons in a gauge theory with an arbitrary gauge
group that is maximally broken.Comment: 48 pages, uses revte
Counting Yang-Mills Dyons with Index Theorems
We count the supersymmetric bound states of many distinct BPS monopoles in
N=4 Yang-Mills theories and in pure N=2 Yang-Mills theories. The novelty here
is that we work in generic Coulombic vacua where more than one adjoint Higgs
fields are turned on. The number of purely magnetic bound states is again found
to be consistent with the electromagnetic duality of the N=4 SU(n) theory, as
expected. We also count dyons of generic electric charges, which correspond to
1/4 BPS dyons in N=4 theories and 1/2 BPS dyons in N=2 theories. Surprisingly,
the degeneracy of dyons is typically much larger than would be accounted for by
a single supermultiplet of appropriate angular momentum, implying many
supermutiplets of the same charge and the same mass.Comment: 34 pages, 1 figure, LaTe
Observables and Correlators in Nonrelativistic ABJM Theory
Non-relativistic ABJM theory is defined by Galilean limit of mass-deformed
N=6 Chern-Simons theory. Holographic string theory dual to the theory is not
known yet. To understand features candidate gravity dual might exhibit, we
examine local and nonlocal physical observables and their correlations in the
non-relativistic ABJM theory. We show that gauge invariant local observables
correspond to zero-norm states and that correlation functions among them are
trivial. We also show that a particular class of nonlocal observables, Wilson
loops, are topological in the sense that their correlation functions coincide
with those of pure Chern-Simons theory. We argue that the theory is
nevertheless physical and illustrate several physical observables whose
correlation functions are nontrivial. We also study quantum aspects. We show
that Chern-Simons level is finitely renormalized and that dilatation operator
acting on spin chain is trivial at planar limit. These results all point to
string scale geometry of gravity dual and to intriguing topological and
tensionless nature of dual string defined on it.Comment: 1+30 pages, no figure, v2. typos fixed and references adde
Quantum 1/4 BPS Dyons
Classical properties of 1/4 BPS dyons were previously well understood both in
field theory context and in string theory context. Its quantum properties,
however, have been more difficult to probe, although the elementary information
of the supermultiplet structures is known from a perturbative construction.
Recently, a low energy effective theory of monopoles was constructed and argued
to contain these dyons as quantum bound states. In this paper, we find these
dyonic bound states explicitly in the N=4 supersymmetric low energy effective
theory. After identifying the correct angular momentum operators, we motivate
an anti-self-dual ansatz for all BPS bound states. The wavefunctions are found
explicitly, whose spin contents and degeneracies match exactly the expected
results.Comment: 20 pages, no figure
Gibrat's law for cities: uniformly most powerful unbiased test of the Pareto against the lognormal
We address the general problem of testing a power law distribution versus a
log-normal distribution in statistical data. This general problem is
illustrated on the distribution of the 2000 US census of city sizes. We provide
definitive results to close the debate between Eeckhout (2004, 2009) and Levy
(2009) on the validity of Zipf's law, which is the special Pareto law with tail
exponent 1, to describe the tail of the distribution of U.S. city sizes.
Because the origin of the disagreement between Eeckhout and Levy stems from the
limited power of their tests, we perform the {\em uniformly most powerful
unbiased test} for the null hypothesis of the Pareto distribution against the
lognormal. The -value and Hill's estimator as a function of city size lower
threshold confirm indubitably that the size distribution of the 1000 largest
cities or so, which include more than half of the total U.S. population, is
Pareto, but we rule out that the tail exponent, estimated to be ,
is equal to 1. For larger ranks, the -value becomes very small and Hill's
estimator decays systematically with decreasing ranks, qualifying the lognormal
distribution as the better model for the set of smaller cities. These two
results reconcile the opposite views of Eeckhout (2004, 2009) and Levy (2009).
We explain how Gibrat's law of proportional growth underpins both the Pareto
and lognormal distributions and stress the key ingredient at the origin of
their difference in standard stochastic growth models of cities
\cite{Gabaix99,Eeckhout2004}.Comment: 7 pages + 2 figure
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