3,625 research outputs found
Slavnov-Taylor identities, non-commutative gauge theories and infrared divergences
In this work we clarify some properties of the one-loop IR divergences in
non-Abelian gauge field theories on non-commutative 4-dimensional Moyal space.
Additionally, we derive the tree-level Slavnov-Taylor identities relating the
two, three and four point functions, and verify their consistency with the
divergent one-loop level results. We also discuss the special case of two
dimensions.Comment: 21 pages, 3 figures; v2: minor corrections and references adde
Similarities of gauge and gravity amplitudes
We review recent progress in computations of amplitudes in gauge theory and
gravity. We compare the perturbative expansion of amplitudes in N=4 super
Yang-Mills and N=8 supergravity and discuss surprising similarities.Comment: Talk presented by Harald Ita at "Continuous Advances in QCD 2006", 7
page
Perturbative Gravity and Twistor Space
The recent progress in computing gauge theory amplitudes can be extended, in
many cases, to theories incorporating gravity. This has improved our
understanding of the perturbative expansion of N=8 supergravity supporting the
``no-triangle hypothesis'' that N=8 one-loop amplitudes may be expressed in
terms of scalar box integral functions.Comment: Talk presented by N. E. J. Bjerrum-Bohr at Loop and Legs 2006, 5
page
Unbiased All-Optical Random-Number Generator
The generation of random bits is of enormous importance in modern information
science. Cryptographic security is based on random numbers which require a
physical process for their generation. This is commonly performed by hardware
random number generators. These exhibit often a number of problems, namely
experimental bias, memory in the system, and other technical subtleties, which
reduce the reliability in the entropy estimation. Further, the generated
outcome has to be post-processed to "iron out" such spurious effects. Here, we
present a purely optical randomness generator, based on the bi-stable output of
an optical parametric oscillator. Detector noise plays no role and no further
post-processing is required. Upon entering the bi-stable regime, initially the
resulting output phase depends on vacuum fluctuations. Later, the phase is
rigidly locked and can be well determined versus a pulse train, which is
derived from the pump laser. This delivers an ambiguity-free output, which is
reliably detected and associated with a binary outcome. The resulting random
bit stream resembles a perfect coin toss and passes all relevant randomness
measures. The random nature of the generated binary outcome is furthermore
confirmed by an analysis of resulting conditional entropies.Comment: 10 pages, 4 figure
Perturbative Computation of Glueball Superpotentials for SO(N) and USp(N)
We use the superspace method of hep-th/0211017 to prove the matrix model
conjecture for N=1 USp(N) and SO(N) gauge theories in four dimensions. We
derive the prescription to relate the matrix model to the field theory
computations. We perform an explicit calculation of glueball superpotentials.
The result is consistent with field theory expectations.Comment: 24 pages, 10 figure
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