30 research outputs found
Generalized quark-antiquark potential in AdS/CFT
In this talk we present a family of Wilson loop operators which continuously
interpolates between the 1/2 BPS line and the antiparallel lines, and can be
thought of as calculating a generalization of the quark--antiquark potential
for the gauge theory on S^3 x R. We evaluate the first two orders of these
loops perturbatively both in the gauge and string theory. We obtain analytical
expressions in a systematic expansion around the 1/2 BPS configuration, and
comment on possible all-loop patterns for these Wilson loops.Comment: 6 pages. Proceedings of the "XVII European Workshop on String Theory
2011", Padova, Italy, 5-9 September 201
Reciprocity of gauge operators in N=4 SYM
A recently discovered generalized Gribov-Lipatov reciprocity holds for the
anomalous dimensions of various twist operators in N=4 SYM. Here, we consider a
class of scaling psu(2,2|4) operators that reduce at one-loop to twist-3
maximal helicity gluonic operators. We extract from the asymptotic long-range
Bethe Ansatz a closed expression for the spin dependent anomalous dimension at
four loop order and provide a complete proof of reciprocity. We comment about
the interplay with possible, yet unknown, wrapping corrections.Comment: Latex, JHEP style, 36 pages, v2: references adde
Holography on the lattice: the string worldsheet perspective
We review the study, on the lattice, of the Green-Schwarz gauge-fixed string
action describing worldsheet fluctuations about the minimal surface
holographically dual to the null cusp Wilson loop, useful to evaluate the cusp
anomaly of N = 4 super Yang-Mills (sYM). We comment on discretization,
numerical explorations and challenges for the non-perturbative study of this
benchmark model of gauge-fixed worldsheet actions.Comment: Invited review to be published on European Physics Journal - Special
Topics, 24 pages, 1 figur
Supersphere non-linear sigma model on the lattice
Two-dimensional O(N) non-linear sigma models are exactly solvable theories and have many applications, from statistical mechanics to their use as QCD toy models. We consider a supersymmetric extension, the non-linear sigma model on the supersphere~SN+2mâ1|2mâĄOSP(N+2m|2m)OSP(N+2mâ1|2m) . We briefly describe its renormalization properties and lattice discretization, and present a strategy for numerical simulations together with some preliminary numerical results
One-loop spectroscopy of semiclassically quantized strings: bosonic sector
We make a further step in the analytically exact quantization of spinning string states in semiclassical approximation, by evaluating the exact one-loop partition function for a class of two-spin string solutions for which quadratic fluctuations form a non-trivial system of coupled modes. This is the case of a folded string in the SU(2) sector, in the limit described by a quantum LandauâLifshitz model. The same applies to the full bosonic sector of fluctuations over the folded spinning string in AdS5 with an angular momentum J in S5. Fluctuations are governed by a special class of fourth-order differential operators, with coefficients being meromorphic functions on the torus, which we are able to solve exactly
Four loop reciprocity of twist two operators in N=4 SYM
The four loop universal anomalous dimension of twist-2 operators in N=4 SYM
has been recently conjectured. In this paper, we prove that it obeys a
generalized Gribov-Lipatov reciprocity, previously known to hold at the three
loop level.Comment: 15 pages, v3: Appendix A.3 added, main body shortened, version
accepted in JHE
A solution to the 4-tachyon off-shell amplitude in cubic string field theory
We derive an analytic series solution of the elliptic equations providing the
4-tachyon off-shell amplitude in cubic string field theory (CSFT). From such a
solution we compute the exact coefficient of the quartic effective action
relevant for time dependent solutions and we derive the exact coefficient of
the quartic tachyon coupling. The rolling tachyon solution expressed as a
series of exponentials is studied both using level-truncation
computations and the exact 4-tachyon amplitude. The results for the level
truncated coefficients are shown to converge to those derived using the exact
string amplitude. The agreement with previous work on the subject, both on the
quartic tachyon coupling and on the CSFT rolling tachyon, is an excellent test
for the accuracy of our off-shell solution.Comment: 26 pages, 5 figure
Generalized quark-antiquark potential at weak and strong coupling
We study a two-parameter family of Wilson loop operators in N=4
supersymmetric Yang-Mills theory which interpolates smoothly between the 1/2
BPS line or circle and a pair of antiparallel lines. These observables capture
a natural generalization of the quark-antiquark potential. We calculate these
loops on the gauge theory side to second order in perturbation theory and in a
semiclassical expansion in string theory to one-loop order. The resulting
determinants are given in integral form and can be evaluated numerically for
general values of the parameters or analytically in a systematic expansion
around the 1/2 BPS configuration. We comment about the feasibility of deriving
all-loop results for these Wilson loops.Comment: 43 pages: 15 comprising the main text and 25 for detailed appendice
Gauge invariant finite size spectrum of the giant magnon
It is shown that the finite size corrections to the spectrum of the giant
magnon solution of classical string theory, computed using the uniform
light-cone gauge, are gauge invariant and have physical meaning. This is seen
in two ways: from a general argument where the single magnon is made gauge
invariant by putting it on an orbifold as a wrapped state obeying the level
matching condition as well as all other constraints, and by an explicit
calculation where it is shown that physical quantum numbers do not depend on
the uniform light-cone gauge parameter. The resulting finite size effects are
exponentially small in the -charge and the exponent (but not the prefactor)
agrees with gauge theory computations using the integrable Hubbard model.Comment: 12 pages, some clarifications, references adde