1,557 research outputs found
The Complete KLT-Map Between Gravity and Gauge Theories
We present the complete map of any pair of super Yang-Mills theories to
supergravity theories as dictated by the KLT relations in four dimensions.
Symmetries and the full set of associated vanishing identities are derived. A
graphical method is introduced which simplifies counting of states, and helps
in identifying the relevant set of symmetries.Comment: 41 pages, 16 figures, published version, typos corrected, references
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Leading quantum gravitational corrections to QED
We consider the leading post-Newtonian and quantum corrections to the
non-relativistic scattering amplitude of charged spin-1/2 fermions in the
combined theory of general relativity and QED. The coupled Dirac-Einstein
system is treated as an effective field theory. This allows for a consistent
quantization of the gravitational field. The appropriate vertex rules are
extracted from the action, and the non-analytic contributions to the 1-loop
scattering matrix are calculated in the non-relativistic limit. The
non-analytical parts of the scattering amplitude are known to give the long
range, low energy, leading quantum corrections, are used to construct the
leading post-Newtonian and quantum corrections to the two-particle
non-relativistic scattering matrix potential for two massive fermions with
electric charge.Comment: 14 pages, 29 figures, format RevTex
Proof of Gravity and Yang-Mills Amplitude Relations
Using BCFW on-shell recursion techniques, we prove a sequence of explicit
n-point Kawai-Lewellen-Tye relations between gravity and Yang-Mills amplitudes
at tree level.Comment: 17 pages, no figures, JHE
The Kinematic Algebra From the Self-Dual Sector
We identify a diffeomorphism Lie algebra in the self-dual sector of
Yang-Mills theory, and show that it determines the kinematic numerators of
tree-level MHV amplitudes in the full theory. These amplitudes can be computed
off-shell from Feynman diagrams with only cubic vertices, which are dressed
with the structure constants of both the Yang-Mills colour algebra and the
diffeomorphism algebra. Therefore, the latter algebra is the dual of the colour
algebra, in the sense suggested by the work of Bern, Carrasco and Johansson. We
further study perturbative gravity, both in the self-dual and in the MHV
sectors, finding that the kinematic numerators of the theory are the BCJ
squares of the Yang-Mills numerators.Comment: 29 pages, 5 figures. v2: references added, published versio
Minimal Basis for Gauge Theory Amplitudes
Identities based on monodromy for integrations in string theory are used to
derive relations between different color ordered tree-level amplitudes in both
bosonic and supersymmetric string theory. These relations imply that the color
ordered tree-level n-point gauge theory amplitudes can be expanded in a minimal
basis of (n-3)! amplitudes. This result holds for any choice of polarizations
of the external states and in any number of dimensions.Comment: v2: typos corrected, some rephrasing of the general discussion.
Captions to figures added. Version to appear in PRL. 4 pages, 5 figure
Note on graviton MHV amplitudes
Two new formulas which express n-graviton MHV tree amplitudes in terms of
sums of squares of n-gluon amplitudes are discussed. The first formula is
derived from recursion relations. The second formula, simpler because it
involves fewer permutations, is obtained from the variant of the Berends,
Giele, Kuijf formula given in Arxiv:0707.1035.Comment: 10 page
Benchmarking acid and base dopants with respect to enabling the ice V to XIII and ice VI to XV hydrogen-ordering phase transitions
Doping the hydrogen-disordered phases of ice V, VI and XII with hydrochloric
acid (HCl) has led to the discovery of their hydrogen-ordered counterparts ices
XIII, XV and XIV. Yet, the mechanistic details of the hydrogen-ordering phase
transitions are still not fully understood. This includes in particular the
role of the acid dopant and the defect dynamics that it creates within the
ices. Here we investigate the effects of several acid and base dopants on the
hydrogen ordering of ices V and VI with calorimetry and X-ray diffraction. HCl
is found to be most effective for both phases which is attributed to a
favourable combination of high solubility and strong acid properties which
create mobile H3O+ defects that enable the hydrogen-ordering processes.
Hydrofluoric acid (HF) is the second most effective dopant highlighting that
the acid strengths of HCl and HF are much more similar in ice than they are in
liquid water. Surprisingly, hydrobromic acid doping facilitates hydrogen
ordering in ice VI whereas only a very small effect is observed for ice V.
Conversely, lithium hydroxide (LiOH) doping achieves a performance comparable
to HF-doping in ice V but it is ineffective in the case of ice VI. Sodium
hydroxide, potassium hydroxide (as previously shown) and perchloric acid doping
are ineffective for both phases. These findings highlight the need for future
computational studies but also raise the question why LiOH-doping achieves
hydrogen-ordering of ice V whereas potassium hydroxide doping is most effective
for the 'ordinary' ice Ih.Comment: 18 pages, 7 figures, 1 tabl
Time transients in the quantum corrected Newtonian potential induced by a massless nonminimally coupled scalar field
We calculate the one loop graviton vacuum polarization induced by a massless,
nonminimally coupled scalar field on Minkowski background. We make use of the
Schwinger-Keldysh formalism, which allows us to study time dependent phenomena.
As an application we compute the leading quantum correction to the Newtonian
potential of a point particle. The novel aspect of the calculation is the use
of the Schwinger-Keldysh formalism, within which we calculate the time
transients induced by switching on of the graviton-scalar coupling.Comment: 22 pages, 5 figures; detailed calculation of the graviton vacuum
polarization moved to the new Appendix; matches published versio
Low-lying spectra in anharmonic three-body oscillators with a strong short-range repulsion
Three-body Schroedinger equation is studied in one dimension. Its two-body
interactions are assumed composed of the long-range attraction (dominated by
the L-th-power potential) in superposition with a short-range repulsion
(dominated by the (-K)-th-power core) plus further subdominant power-law
components if necessary. This unsolvable and non-separable generalization of
Calogero model (which is a separable and solvable exception at L = K = 2) is
presented in polar Jacobi coordinates. We derive a set of trigonometric
identities for the potentials which generalizes the well known K=2 identity of
Calogero to all integers. This enables us to write down the related partial
differential Schroedinger equation in an amazingly compact form. As a
consequence, we are able to show that all these models become separable and
solvable in the limit of strong repulsion.Comment: 18 pages plus 6 pages of appendices with new auxiliary identitie
Note on New KLT relations
In this short note, we present two results about KLT relations discussed in
recent several papers. Our first result is the re-derivation of Mason-Skinner
MHV amplitude by applying the S_{n-3} permutation symmetric KLT relations
directly to MHV amplitude. Our second result is the equivalence proof of the
newly discovered S_{n-2} permutation symmetric KLT relations and the well-known
S_{n-3} permutation symmetric KLT relations. Although both formulas have been
shown to be correct by BCFW recursion relations, our result is the first direct
check using the regularized definition of the new formula.Comment: 15 Pages; v2: minor correction
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