921 research outputs found
Polyakov formulas for GJMS operators from AdS/CFT
We argue that the AdS/CFT calculational prescription for double-trace
deformations leads to a holographic derivation of the conformal anomaly, and
its conformal primitive, associated to the whole family of conformally
covariant powers of the Laplacian (GJMS operators) at the conformal boundary.
The bulk side involves a quantum 1-loop correction to the SUGRA action and the
boundary counterpart accounts for a sub-leading term in the large-N limit. The
sequence of GJMS conformal Laplacians shows up in the two-point function of the
CFT operator dual to a bulk scalar field at certain values of its scaling
dimension. The restriction to conformally flat boundary metrics reduces the
bulk computation to that of volume renormalization which renders the universal
type A anomaly. In this way, we directly connect two chief roles of the
Q-curvature: the main term in Polyakov formulas on one hand, and its relation
to the Poincare metrics of the Fefferman-Graham construction, on the other
hand. We find agreement with previously conjectured patterns including a
generic and simple formula for the type A anomaly coefficient that matches all
reported values in the literature concerning GJMS operators, to our knowledge.Comment: 27 pages, uses JHEP3.cls; eq.(2.4) corrected, refs and comments adde
GJMS-like operators on symmetric 2-tensors and their gravitational duals
We study a family of higher-derivative conformal operators
acting on transverse-traceless symmetric 2-tensors on generic Einstein spaces.
They are a natural generalization of the well-known construction for scalars.
We first provide the alternative description in terms of a bulk
Poincar\'e-Einstein metric by making use of the AdS/CFT dictionary and argue
that their holographic dual generically consists of bulk massive gravitons. At
one-loop quantum level, we put forward a holographic formula for the functional
determinant of the higher-derivative conformal operators in
terms of the functional determinant for massive gravitons with standard and
alternate boundary conditions. The analogous construction for vectors
is worked out as well and we also rewrite the holographic
formula for unconstrained vector and traceless symmetric 2-tensor by decoupling
the longitudinal part.
Finally, we show that the holographic formula provides the necessary building
blocks to address the massless and partially massless bulk gravitons. This is
confirmed in four and six dimensions, verifying full agreement with results
available in the literature.Comment: 15 Pages, 0 figures. Minor change
On the AdS Higher Spin / O(N) Vector Model Correspondence: degeneracy of the holographic image
We explore the conjectured duality between the critical O(N) vector model and
minimal bosonic massless higher spin (HS) theory in AdS. In the boundary free
theory, the conformal partial wave expansion (CPWE) of the four-point function
of the scalar singlet bilinear is reorganized to make it explicitly
crossing-symmetric and closed in the singlet sector, dual to the bulk HS gauge
fields. We are able to analytically establish the factorized form of the fusion
coefficients as well as the two-point function coefficient of the HS currents.
We insist in directly computing the free correlators from bulk graphs with the
unconventional branch. The three-point function of the scalar bilinear turns
out to be an "extremal" one at d=3. The four-leg bulk exchange graph can be
precisely related to the CPWs of the boundary dual scalar and its shadow. The
flow in the IR by Legendre transforming at leading 1/N, following the pattern
of double-trace deformations, and the assumption of degeneracy of the hologram
lead to the CPWE of the scalar four-point function at IR. Here we confirm some
previous results, obtained from more involved computations of skeleton graphs,
as well as extend some of them from d=3 to generic dimension 2<d<4.Comment: 22 pages, 5 figure
Partition functions and double-trace deformations in AdS/CFT
We study the effect of a relevant double-trace deformation on the partition
function (and conformal anomaly) of a CFT at large N and its dual picture in
AdS. Three complementary previous results are brought into full agreement with
each other: bulk and boundary computations, as well as their formal identity.
We show the exact equality between the dimensionally regularized partition
functions or, equivalently, fluctuational determinants involved. A series of
results then follows: (i) equality between the renormalized partition functions
for all d; (ii) for all even d, correction to the conformal anomaly; (iii) for
even d, the mapping entails a mixing of UV and IR effects on the same side
(bulk) of the duality, with no precedent in the leading order computations; and
finally, (iv) a subtle relation between overall coefficients, volume
renormalization and IR-UV connection. All in all, we get a clean test of the
AdS/CFT correspondence beyond the classical SUGRA approximation in the bulk and
at subleading O(1) order in the large-N expansion on the boundary.Comment: 18 pages, uses JHEP3.cls. Published JHEP versio
Propagators and WKB-exactness in the plane wave limit of AdSxS
Green functions for the scalar, spinor and vector fields in a plane wave
geometry arising as a Penrose limit of are obtained. The
Schwinger-DeWitt technique directly gives the results in the plane wave
background, which turns out to be WKB-exact. Therefore the structural
similarity with flat space results is unveiled. In addition, based on the local
character of the Penrose limit, it is claimed that for getting the correct
propagators in the limit one can rely on the first terms of the direct geodesic
contribution in the Schwinger-DeWitt expansion of the original propagators .
This is explicitly shown for the Einstein Static Universe, which has the same
Penrose limit as with equal radii, and for a number of other
illustrative cases.Comment: 18 pages, late
The FENIKS Survey: Spectroscopic Confirmation of Massive Quiescent Galaxies at z ~ 3-5
The measured ages of massive, quiescent galaxies at imply that
massive galaxies quench as early as . While the number of
spectroscopic confirmations of quiescent galaxies at has increased over
the years, there are only a handful at . We report spectroscopic
redshifts of one secure () and two tentative (, )
massive () quiescent galaxies with 11 hours of
Keck/MOSFIRE -band observations. Our candidates were selected from the
FENIKS survey, which uses deep Gemini/Flamingos-2 imaging optimized
for increased sensitivity to the characteristic red colors of galaxies at with strong Balmer/4000 \AA\ breaks. The rest-frame and
colors of 3/4 quiescent candidates are consistent with Gyr old stellar
populations. This places these galaxies as the oldest objects at these
redshifts, and challenges the notion that quiescent galaxies at are all
recently-quenched, "post-starburst'' galaxies. Our spectroscopy shows that the
other quiescent-galaxy candidate is a broad-line AGN () with strong,
redshifted +[O III] emission with a velocity offset km/s,
indicative of a powerful outflow. The star-formation history of our highest
redshift candidate suggests that its progenitor was already in place by , reaching 10 by . These observations
reveal the limit of what is possible with deep near-infrared photometry and
targeted spectroscopy from the ground and demonstrate that secure spectroscopic
confirmation of quiescent galaxies at is only feasible with JWST.Comment: 20 pages, 11 figures, submitted to Ap
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory
The Auger Engineering Radio Array (AERA) is part of the Pierre Auger
Observatory and is used to detect the radio emission of cosmic-ray air showers.
These observations are compared to the data of the surface detector stations of
the Observatory, which provide well-calibrated information on the cosmic-ray
energies and arrival directions. The response of the radio stations in the 30
to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of
the incoming electric field. For the latter, the energy deposit per area is
determined from the radio pulses at each observer position and is interpolated
using a two-dimensional function that takes into account signal asymmetries due
to interference between the geomagnetic and charge-excess emission components.
The spatial integral over the signal distribution gives a direct measurement of
the energy transferred from the primary cosmic ray into radio emission in the
AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air
shower arriving perpendicularly to the geomagnetic field. This radiation energy
-- corrected for geometrical effects -- is used as a cosmic-ray energy
estimator. Performing an absolute energy calibration against the
surface-detector information, we observe that this radio-energy estimator
scales quadratically with the cosmic-ray energy as expected for coherent
emission. We find an energy resolution of the radio reconstruction of 22% for
the data set and 17% for a high-quality subset containing only events with at
least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO
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