236,694 research outputs found
The Intrinsic Coupling in Integrable Quantum Field Theories
The intrinsic 4-point coupling, defined in terms of a truncated 4-point
function at zero momentum, provides a well-established measure for the
interaction strength of a QFT. We show that this coupling can be computed
non-perturbatively and to high accuracy from the form factors of an
(integrable) QFT. The technique is illustrated and tested with the Ising model,
the XY-model and the O(3) nonlinear sigma-model. The results are compared to
those from high precision lattice simulations.Comment: 69 pages, Late
A QUDA-branch to compute disconnected diagrams in GPUs
Although QUDA allows for an efficient computation of many QCD quantities, it
is surprinsingly lacking tools to evaluate disconnected diagrams, for which
GPUs are specially well suited. We aim to fill this gap by creating our own
branch of QUDA, which includes new kernels and functions required to calculate
fermion loops using several methods and fermionic regularizations.Comment: 7 pages, 4 figures. Proceedings of the talk given during the code
session of the 31st International Symposium on Lattice Field Theory, July 29
- August 3, 2013, Mainz, Germany. Added a missing reference (number [4]
Higher Derivative Terms from Threebranes in F Theory
The computation of higher derivative corrections to the low energy effective
actions of gauge theories is considered. In particular, higher
derivative corrections are computed for four dimensional super
Yang-Mills theory with gauge group SU(2) and hypermultiplets in the
fundamental representation. The four derivative terms computed in an approach
which realizes the gauge theory as the world volume theory of three branes in F
theory are in agreement with the field theory result.Comment: 13 pages, uses harvmac, presentation improved, references adde
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