2,187 research outputs found
Gravity and axions from a random UV QFT
It is postulated that the UV QFT is enormous and random. The coupling of the
Standard Model to such QFT is analyzed. It is argued that massless 4d gravity
and axions are general avatars of the postulate. The equivalence principle
emerges naturally as well as a concrete set of sources for its breaking. The
axion scale is related to the 4d Planck scale as , where is the
"number of colors" of the (almost) hidden UV CFT.Comment: Latex, 39 page
Gravitational and axial anomalies for generalized Euclidean Taub-NUT metrics
The gravitational anomalies are investigated for generalized Euclidean
Taub-NUT metrics which admit hidden symmetries analogous to the Runge-Lenz
vector of the Kepler-type problem. In order to evaluate the axial anomalies,
the index of the Dirac operator for these metrics with the APS boundary
condition is computed. The role of the Killing-Yano tensors is discussed for
these two types of quantum anomalies.Comment: 23 page
Generalized hidden symmetries and the Kerr-Sen black hole
We elaborate on basic properties of generalized Killing-Yano tensors which
naturally extend Killing-Yano symmetry in the presence of skew-symmetric
torsion. In particular, we discuss their relationship to Killing tensors and
the separability of various field equations. We further demonstrate that the
Kerr-Sen black hole spacetime of heterotic string theory, as well as its
generalization to all dimensions, possesses a generalized closed conformal
Killing-Yano 2-form with respect to a torsion identified with the 3-form
occuring naturally in the theory. Such a 2-form is responsible for complete
integrability of geodesic motion as well as for separability of the scalar and
Dirac equations in these spacetimes.Comment: 33 pages, no figure
Conjecture on Hidden Superconformal Symmetry of N=4 Supergravity
We argue that the observed UV finiteness of the 3-loop extended
supergravities may be a manifestation of a hidden local superconformal symmetry
of supergravity. We focus on the SU(2,2|4) dimensionless superconformal model.
In Poincare gauge where the compensators are fixed to phi^2= 6 M_P^2 this model
becomes a pure classical N=4 Einstein supergravity. We argue that in N=4 the
higher-derivative superconformal invariants like phi^{-4}W^2 \bar W^2 and the
consistent local anomaly delta (ln phi W^2) are not available. This conjecture
on hidden local N=4 superconformal symmetry of Poincare supergravity may be
supported by subsequent loop computations.Comment: 14 p A discussion of half-maximal D=6 superconformal models is adde
Survey of Two-Time Physics
Two-time physics (2T) is a general reformulation of one-time physics (1T)
that displays previously unnoticed hidden symmetries in 1T dynamical systems
and establishes previously unknown duality type relations among them. This may
play a role in displaying the symmetries and constructing the dynamics of
little understood systems, such as M-theory. 2T physics describes various 1T
dynamical systems as different d-dimensional ``holographic'' views of the same
2T system in dimensions. The ``holography'' is due to gauge symmetries
that tend to reduce the number of effective dimensions. Different 1T evolutions
(i.e. different Hamiltonians) emerge from the same 2T theory when gauge fixing
is done with different embeddings of d dimensions inside d+2 dimensions. Thus,
in the 2T setting, the distinguished 1T which we call ``time'' is a gauge
dependent concept. The 2T action has also a global SO(d,2) symmetry in flat
spacetime, or a more general d+2 symmetry in curved spacetime, under which all
dimensions are on an equal footing. This symmetry is observable in many 1T
systems, but it remained unknown until discovered in the 2T formalism. 2T
physics has mainly been developed in the context of particles, including spin
and supersymmetry, but some advances have also been made with strings and
p-branes, and insights for M-theory have already emerged. In the case of
particles, there exists a general worldline formulation with background fields,
as well as a field theory formulation, both described in terms of fields that
depend on d+2 coordinates. The Standard Model of particle physics can be
regarded as a gauge fixed form of a 2T theory in 4+2 dimensions. These facts
already provide evidence for a new type of higher dimensional unification.Comment: Latex, 22 pages, 1 figur
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