141 research outputs found
Three-loop renormalization of the N=1, N=2, N=4 supersymmetric Yang-Mills theories
We calculate the renormalization constants of the N=1, N=2, N=4
supersymmetric Yang-Mills theories in an arbitrary covariant gauge in the
dimensional reduction scheme up to three loops. We have found, that the
beta-functions for N=1 and N=4 SYM theories are the same from the different
triple vertices. This means that the dimensional reduction scheme works
correctly in these models up to third order of perturbative theory.Comment: 6 page
Five-loop anomalous dimension at critical wrapping order in N=4 SYM
We compute the anomalous dimension of a length-five operator at five-loop
order in the SU(2) sector of N=4 SYM theory in the planar limit. This is
critical wrapping order at five loops. The result is obtained perturbatively by
means of N=1 superspace techniques. Our result from perturbation theory
confirms explicitly the formula conjectured in arXiv:0901.4864 for the
five-loop anomalous dimension of twist-three operators. We also explicitly
obtain the same result by employing the recently proposed Y-system.Comment: LaTeX, feynmp, 34 pages, 21 figures, 8 table
Anomalous dimensions at four loops in N=6 superconformal Chern-Simons theories
In arXiv:0908.2463 we computed the four-loop correction to a function
depending on the 't Hooft coupling(s) that appears in the magnon dispersion
relation of the spin chains derived from single trace operators in N=6
superconformal Chern-Simons theories. In this paper we give detailed
descriptions of this calculation and the computation of the four-loop wrapping
corrections for a length four operator in the 20 of SU(4), the R-symmetry group
for these theories. Here, we give all relevant Feynman diagrams and loop
integrals explicitly, and also demonstrate the cancellation of double poles in
the logarithm of the renormalization constant.Comment: LaTeX, feynmp, 70 pages; v2: signs of three diagrams due to
inconsistent Feynman rules corrected, modifying the final result, typos
corrected, formulations improve
Commuting Conformal and Dual Conformal Symmetries in the Regge limit
In this paper we continue our study of the dual SL(2,C) symmetry of the BFKL
equation, analogous to the dual conformal symmetry of N=4 Super Yang Mills. We
find that the ordinary and dual SL(2,C) symmetries do not generate a Yangian,
in contrast to the ordinary and dual conformal symmetries in the
four-dimensional gauge theory. The algebraic structure is still reminiscent of
that of N=4 SYM, however, and one can extract a generator from the dual SL(2,C)
close to the bi-local form associated with Yangian algebras. We also discuss
the issue of whether the dual SL(2,C) symmetry, which in its original form is
broken by IR effects, is broken in a controlled way, similar to the way the
dual conformal symmetry of N=4 satisfies an anomalous Ward identity. At least
for the lowest orders it seems possible to recover the dual SL(2,C) by
deforming its representation, keeping open the possibility that it is an exact
symmetry of BFKL.Comment: 24 page
Single impurity operators at critical wrapping order in the beta-deformed N=4 SYM
We study the spectrum of one single magnon in the superconformal
beta-deformed N=4 SYM theory in the planar limit. We compute the anomalous
dimensions of one-impurity operators O_{1,L}= tr(phi Z^{L-1}), including
wrapping contributions at their critical order L.Comment: LaTeX, feynmf, Metapost, 20 pages, 11 figures, v2: results up to 11
loops completed, appendix on integral calculation extende
Wrapping effects in supersymmetric gauge theories
Several perturbative computations of finite-size effects, performed on the
gauge side of the AdS/CFT correspondence by means of superspace techniques, are
presented. First, wrapping effects are analyzed in the standard N = 4 theory,
by means of the calculation of the four-loop anomalous dimension of the Konishi
operator. Then, a similar computation at five loops is described. Afterwards,
finite-size effects are studied in the beta-deformed case, where thanks to the
reduced number of supersymmetries the simpler class of single-impurity
operators can be considered, so that the leading corrections to the anomalous
dimensions at generic order can be reduced to the computation of a class of
integrals. Explicit results are given up to eleven loops. A further chapter is
dedicated to the computation of the leading finite-size effects on operators
dual to open strings. In the end, some comments are made and proposals for
future developments are discussed.Comment: Ph.D. thesi
Extended Y-system for the correspondence
We study the analytic properties of the Y functions. It is
shown that the TBA equations, including the dressing factor, can be obtained
from the Y-system with some additional information on the square-root
discontinuities across semi-infinite segments in the complex plane. The
Y-system extended by the discontinuity relations constitutes a fundamental set
of local functional constraints that can be easily transformed into integral
form through Cauchy's theorem.Comment: LaTeX2e, 42 pages, 7 figures. v2: 45 pages, references and a new
appendix included, typos corrected. v3: minor typos corrected, references
adde
Orbifolded Konishi from the Mirror TBA
Starting with a discussion of the general applicability of the simplified
mirror TBA equations to simple deformations of the AdS_5 x S^5 superstring, we
proceed to study a specific type of orbifold to which the undeformed simplified
TBA equations directly apply. We then use this set of equations, as well as
Luscher's approach, to determine the NLO wrapping correction to the energy of
what we call the orbifolded Konishi state, and show that they perfectly agree.
In addition we discuss wrapping corrections to the ground state energy of the
orbifolded model under consideration.Comment: 26 pages, 5 figures, v2: corrected typos, added a short discussion on
the ground state of the model; as submitted to J. Phys.
Twisted Bethe equations from a twisted S-matrix
All-loop asymptotic Bethe equations for a 3-parameter deformation of
AdS5/CFT4 have been proposed by Beisert and Roiban. We propose a Drinfeld twist
of the AdS5/CFT4 S-matrix, together with c-number diagonal twists of the
boundary conditions, from which we derive these Bethe equations. Although the
undeformed S-matrix factorizes into a product of two su(2|2) factors, the
deformed S-matrix cannot be so factored. Diagonalization of the corresponding
transfer matrix requires a generalization of the conventional algebraic Bethe
ansatz approach, which we first illustrate for the simpler case of the twisted
su(2) principal chiral model. We also demonstrate that the same twisted Bethe
equations can alternatively be derived using instead untwisted S-matrices and
boundary conditions with operatorial twists.Comment: 42 pages; v2: a new appendix on sl(2) grading, 2 additional
references, and some minor changes; v3: improved Appendix D, additional
references, and further minor changes, to appear in JHE
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