13,689 research outputs found
Amplitude Relations in Non-linear Sigma Model
In this paper, we investigate tree-level scattering amplitude relations in
non-linear sigma model. We use Cayley parametrization. As was shown in
the recent works [23,24] both on-shell amplitudes and off-shell currents with
odd points have to vanish under Cayley parametrization. We prove the off-shell
identity and fundamental BCJ relation for even-point currents. By taking
the on-shell limits of the off-shell relations, we show that the color-ordered
tree amplitudes with even points satisfy -decoupling identity and
fundamental BCJ relation, which have the same formations within Yang-Mills
theory. We further state that all the on-shell general KK, BCJ relations as
well as the minimal-basis expansion are also satisfied by color-ordered tree
amplitudes. As a consequence of the relations among color-ordered amplitudes,
the total -point tree amplitudes satisfy DDM form of color decomposition as
well as KLT relation.Comment: 27 pages, 8 figures, 4 tables, JHEP style, improved versio
The Universal Property of the Entropy Sum of Black Holes in All Dimensions
It is proposed by Cvetic et al [Phys. Rev. Lett. 106 (2011) 121301] that the
product of all horizon areas for general rotating multi-change black holes has
universal expressions independent of the mass. When we consider the product of
all horizon entropies, however, the mass will be present in some cases, while
another new universal property [JHEP 1401 (2014) 031] is preserved, which is
more general and says that the sum of all horizon entropies depends only on the
coupling constants of the theory and the topology of the black hole. The
property has been studied in limited dimensions and the generalization in
arbitrary dimensions is not straight-forward. In this Letter, we prove a useful
formula, which makes it possible to investigate this conjectured universality
in arbitrary dimensions for the maximally symmetric black holes in general
Lovelock gravity and gravity. We also propose an approach to compute the
entropy sum of general Kerr-(anti-)de-Sitter black holes in arbitrary
dimensions. In all these cases, we prove that the entropy sum only depends on
the coupling constants and the topology of the black hole.Comment: 16 pages,no figures;v2: 17 pages, references added, minor
corrections/modifications; v3: 16 pages, added references, correct some
expressons, added equation (16) to make the context more clear, to appear in
PL
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