79 research outputs found
Momentum space conformal three-point functions of conserved currents and a general spinning operator
We construct conformal three-point functions in momentum space with a general
tensor and conserved currents of spin and . While conformal correlators
in momentum space have been studied especially in the connection with
cosmology, correlators involving a tensor of general spin and scaling dimension
have not been studied very much yet. Such a direction is unavoidable when we go
beyond three-point functions because general tensors always appear as an
intermediate state. In this paper, as a first step, we solve the Ward-Takahashi
identities for correlators of a general tensor and conserved currents. In
particular we provide their expression in terms of the so-called triple-
integrals and a differential operator which relates triple- integrals with
different indices. For several correlators, closed forms without the
differential operator are also found.Comment: 24+16 page
Entanglement Entropy of de Sitter Space \alpha-Vacua
We generalize the analysis of arXiv:1210.7244 to de Sitter space \alpha-vacua
and compute the entanglement entropy of a free scalar for the half-sphere at
late time.Comment: 4 pages, 3 figures. v2: minor changes, published versio
Higgs Mechanism in Nonlocal Field Theories
We study spontaneous gauge symmetry breaking and the Higgs mechanism in
nonlocal field theories. Motivated by the level truncated action of string
field theory, we consider a class of nonlocal field theories with an
exponential factor of the d'Alembertian attached to the kinetic and mass terms.
Modifications of this kind are known to make mild the UV behavior of loop
diagrams and thus have been studied not only in the context of string theory
but also as an alternative approach to quantum gravity. In this paper we argue
that such a nonlocal theory potentially includes a ghost mode near the nonlocal
scale in the particle spectrum of the symmetry broken phase. This is in sharp
contrast to local field theories and would be an obstruction to making a simple
nonlocal model a UV complete theory. We then discuss a possible way out by
studying nonlocal theories with extra symmetries such as gauge symmetries in
higher spacetime dimensions.Comment: 19 pages, 4 figures; v2: references added, version published in JHE
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