556 research outputs found
Open Semiclassical Strings and Long Defect Operators in AdS/dCFT Correspondence
We consider defect composite operators in a defect superconformal field
theory obtained by inserting an AdS_4 x S^2-brane in the AdS_5 x S^5
background. The one-loop dilatation operator for the scalar sector is
represented by an integrable open spin chain. We give a description to
construct coherent states for the open spin chain. Then, by evaluating the
expectation value of the Hamiltonian with the coherent states in a long
operator limit, a Landau-Lifshitz type of sigma model action is obtained. This
action is also derived from the string action and hence we find a complete
agreement in both SYM and string sides. We see that an SO(3)_H pulsating string
solution is included in the action and its energy completely agrees with the
result calculated in a different method. In addition, we argue that our
procedure would be applicable to other AdS-brane cases.Comment: 22 pages, 1 figure, LaTeX, minor corrections and references added.
v3) some new results added. shortened and accepted version in PR
Causal effects of PetroCaribe on sustainable development: a synthetic control analysis
We examine the causal effects of the energy subsidy programme PetroCaribe in the three dimensions of sustainable development: economic, social and environmental. We use the synthetic control method to construct a counterfactual and compare it to the outcomes of the beneficiary countries and thus estimate the magnitude and direction of the PetroCaribe effect. PetroCaribe had a positive effect on economic growth in most of the beneficiary countries; however, this economic boost was not followed by an improvement in social development. Environmentally, PetroCaribe did not negatively or positively impact the environmental quality of the member countries, in the sense that we do not find a significant effect on the trend of urn:x-wiley:14636786:media:manc12275:manc12275-math-0001 emissions per capita
Systems Simulation Assists Land Capability Estimation in Australia’s Temperate Grasslands
Intensification of production in the water-limited grasslands of temperate Australia has increased the need to quantify their sustainable carrying capacity. Empirical rainfall-based rules for estimating stocking rate fail when used in districts with differing weather patterns, or when soil and pasture resources limit the utilisation of rainfall. Grazing systems simulation should help to overcome these problems because local conditions can be taken into account. This study investigated the impact of soil resources on potential stocking rate, profitability and production risk in a local climatic area of the southern tablelands of NSW, Australia
On Integrability of Classical SuperStrings in AdS_5 x S^5
We explore integrability properties of superstring equations of motion in
AdS_5 x S^5. We impose light-cone kappa-symmetry and reparametrization gauges
and construct a Lax representation for the corresponding Hamiltonian dynamics
on subspace of physical superstring degrees of freedom. We present some
explicit results for the corresponding conserved charges by consistently
reducing the dynamics to AdS_3 x S^3 and AdS_3 x S^1 subsectors containing both
bosonic and fermionic fields.Comment: JHEP style, 32 pages; v2: refined discussion of monodromy, refs adde
Iterated maps for clarinet-like systems
The dynamical equations of clarinet-like systems are known to be reducible to
a non-linear iterated map within reasonable approximations. This leads to time
oscillations that are represented by square signals, analogous to the Raman
regime for string instruments. In this article, we study in more detail the
properties of the corresponding non-linear iterations, with emphasis on the
geometrical constructions that can be used to classify the various solutions
(for instance with or without reed beating) as well as on the periodicity
windows that occur within the chaotic region. In particular, we find a regime
where period tripling occurs and examine the conditions for intermittency. We
also show that, while the direct observation of the iteration function does not
reveal much on the oscillation regime of the instrument, the graph of the high
order iterates directly gives visible information on the oscillation regime
(characterization of the number of period doubligs, chaotic behaviour, etc.)
Semiclassical Strings on AdS_5 x S^5/Z_M and Operators in Orbifold Field Theories
We show agreements, at one-loop level of field theory, between energies of
semiclassical string states on AdS_5 x S^5/Z_M and anomalous dimensions of
operators in N=0,1,2 orbifold field theories originating from N=4 SYM. On field
theory side, one-loop anomalous dimension matrices can be regarded as
Hamiltonians of spin chains with twisted boundary conditions. These are
solvable by Bethe ansatz. On string side, twisted sectors emerge and we obtain
some string configurations in twisted sectors. In SU(2) subsectors, we compare
anomalous dimensions with string energies and see agreements. We also see
agreements between sigma models of both sides in SU(2) and SU(3) subsectors.Comment: LaTeX, 23 pages, 4 figures; v2 minor corrections, added references;
v3 typos corrected, published versio
Two-loop AdS_5 x S^5 superstring: testing asymptotic Bethe ansatz and finite size corrections
We continue the investigation of two-loop string corrections to the energy of
a folded string with a spin S in AdS_5 and an angular momentum J in S^5, in the
scaling limit of large J and S with ell=pi J/(lambda^(1/2) ln S)=fixed. We
compute the generalized scaling function at two-loop order f_2(ell) both for
small and large values of ell matching the predictions based on the asymptotic
Bethe ansatz. In particular, in the small ell expansion, we derive an exact
integral form for the ell-dependent coefficient of the Catalan's constant term
in f_2(ell). Also, by resumming a certain subclass of multi-loop Feynman
diagrams we obtain an exact expression for the leading (ln ell) part of
f(lambda^(1/2), ell) which is valid to any order in the alpha'~1/lambda^(1/2)
expansion. At large ell the string energy has a BMN-like expansion and the
first few leading coefficients are expected to be the same at weak and at
strong coupling. We provide a new example of this non-renormalization for the
term which is generated at two loops in string theory and at one-loop in gauge
theory (sub-sub-leading in 1/J). We also derive a simple algebraic formula for
the term of maximal transcendentality in f_2(ell) expanded at large ell. In the
second part of the paper we initiate the study of 2-loop finite size
corrections to the string energy by formally compactifying the spatial
world-sheet direction in the string action expanded near long fast-spinning
string. We observe that the leading finite-size corrections are of "Casimir"
type coming from terms containing at least one massless propagator. We consider
in detail the one-loop order (reproducing the leading Landau-Lifshitz model
prediction) and then focus on the two-loop contributions to the (1/ln S) term
(for J=0). We find that in a certain regularization scheme used to discard
power divergences the two-loop coefficient of the (1/ln S) term appears to
vanish.Comment: 50 pages, 4 figures v2: typos corrected, references adde
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