43 research outputs found
Pure spinor superstring in AdS_4 x CP^3 with unconstrained ghosts
We construct the action for the pure spinor superstring in the coset
description of AdS_4 x CP^3 superspace, using the variables which solve the
pure spinor condition. As a test of the consistency of the approach, we use the
background field method to verify the absence of central charge at the second
order in the expansion and to show the one-loop finiteness of the effective
action.Comment: 23 pages, 2 figure
Correlators of chiral primaries and 1/8 BPS Wilson loops from perturbation theory
We study at perturbative level the correlation functions of a general class
of 1/8 BPS Wilson loops and chiral primaries in N = 4 Super Yang-Mills theory.
The contours and the location of operator insertions share a sphere S^2
embedded into spacetime and the system preserves at least two supercharges. We
perform explicit two-loop computations, for some particular but still rather
general configuration, that confirm the elegant results expected from
localization procedure. We find notably full consistency with the multi-matrix
model averages, obtained from 2D Yang-Mills theory on the sphere, when
interacting diagrams do not cancel and contribute non-trivially to the final
answer.Comment: 30 pages, 13 figure
Exact supersymmetry on the lattice: the Wess-Zumino model
It is shown that the lattice Wess-Zumino model written in terms of
Ginsparg-Wilson fermions is invariant under a generalized supersymmetry
transformation which is determined by an iterative procedure in the coupling
constant. This transformation is non-linear in the scalar fields and depends on
the superpotential parameters. The implications of this lattice invariance are
discussed.Comment: 3 pages, Lattice2004(theory), Fermilab, June 21-26, 200
Exact lattice Ward-Takahashi identity for the N=1 Wess-Zumino model
We consider a lattice formulation of the four dimensional N=1 Wess-Zumino
model that uses the Ginsparg-Wilson relation. This formulation has an exact
supersymmetry on the lattice. We show that the corresponding Ward-Takahashi
identity is satisfied, both at fixed lattice spacing and in the continuum
limit. The calculation is performed in lattice perturbation theory up to order
in the coupling constant. We also show that this Ward-Takahashi identity
determines the finite part of the scalar and fermion renormalization wave
functions which automatically leads to restoration of supersymmetry in the
continuum limit. In particular, these wave functions coincide in this limit.Comment: 19 pages, 6 figure
Surprises from the resummation of ladders in the ABJ(M) cusp anomalous dimension
We study the cusp anomalous dimension in N=6 ABJ(M) theory, identifying a
scaling limit in which the ladder diagrams dominate. The resummation is encoded
into a Bethe-Salpeter equation that is mapped to a Schroedinger problem,
exactly solvable due to the surprising supersymmetry of the effective
Hamiltonian. In the ABJ case the solution implies the diagonalization of the
U(N) and U(M) building blocks, suggesting the existence of two independent cusp
anomalous dimensions and an unexpected exponentiation structure for the related
Wilson loops. While consistent with previous perturbative analysis, the strong
coupling limit of our result does not agree with the string theory computation,
emphasizing a difference with the analogous resummation in the N=4 case.Comment: 26 pages, 4 figures, references added, published versio
Bremsstrahlung function, leading Luscher correction at weak coupling and localization
We discuss the near BPS expansion of the generalized cusp anomalous dimension
with L units of R-charge. Integrability provides an exact solution, obtained by
solving a general TBA equation in the appropriate limit: we propose here an
alternative method based on supersymmetric localization. The basic idea is to
relate the computation to the vacuum expectation value of certain 1/8 BPS
Wilson loops with local operator insertions along the contour. These
observables localize on a two-dimensional gauge theory on S^2, opening the
possibility of exact calculations. As a test of our proposal, we reproduce the
leading Luscher correction at weak coupling to the generalized cusp anomalous
dimension. This result is also checked against a genuine Feynman diagram
approach in N=4 Super Yang-Mills theory.Comment: 25 pages, 6 figures. References added and typos correcte
In-House Validation and Comparison of Two Wheat (Triticum aestivum) Taxon-Specific Real-Time PCR Methods for GMO Quantification Supported by Droplet Digital PCR
n/
Wess-Zumino model with exact supersymmetry on the lattice
A lattice formulation of the four dimensional Wess-Zumino model that uses
Ginsparg-Wilson fermions and keeps exact supersymmetry is presented. The
supersymmetry transformation that leaves invariant the action at finite lattice
spacing is determined by performing an iterative procedure in the coupling
constant. The closure of the algebra, generated by this transformation is also
showed.Comment: 13 pages. Few references added. New appendix on Ward identity added.
Version to be published in JHE