1,056 research outputs found
The Wealth Defence Industry:A Large-scale Study on Accountancy Firms as Profit Shifting Facilitators
Corporations increasingly engage in innovative âtax planning strategiesâ by shifting profits between jurisdictions. In response, states try to curtail such profit shifting activities while at the same time attempting to retain and attract multinational corporations. We aim to open up this dichotomy between states and corporations and argue that a wealth defence industry of professional service firms plays a crucial role as facilitators. We investigate the subsidiary structure of 27,000 MNCs and show that clients of the Big Four accountancy firms show systematically higher levels of aggressive tax planning strategies than clients of smaller accountancy firms. We specify this effect for three distinct strategies and also uncover marked differences across countries. As such we provide empirical evidence for the systematic involvement of auditors as facilitators in corporate wealth defence
The Wealth Defence Industry:A Large-scale Study on Accountancy Firms as Profit Shifting Facilitators
Writing CFT correlation functions as AdS scattering amplitudes
We explore the Mellin representation of conformal correlation functions
recently proposed by Mack. Examples in the AdS/CFT context reinforce the
analogy between Mellin amplitudes and scattering amplitudes. We conjecture a
simple formula relating the bulk scattering amplitudes to the asymptotic
behavior of Mellin amplitudes and show that previous results on the flat space
limit of AdS follow from our new formula. We find that the Mellin amplitudes
are particularly useful in the case of conformal gauge theories in the planar
limit. In this case, the four point Mellin amplitudes are meromorphic functions
whose poles and their residues are entirely determined by two and three point
functions of single-trace operators. This makes the Mellin amplitudes the ideal
objects to attempt the conformal bootstrap program in higher dimensions.Comment: 23 pages + appendice
Scale-free equilibria of self-gravitating gaseous disks with flat rotation curves
We introduce exact analytical solutions of the steady-state hydrodynamic
equations of scale-free, self-gravitating gaseous disks with flat rotation
curves. We express the velocity field in terms of a stream function and obtain
a third-order ordinary differential equation (ODE) for the angular part of the
stream function. We present the closed-form solutions of the obtained ODE and
construct hydrodynamical counterparts of the power-law and elliptic disks, for
which self-consistent stellar dynamical models are known. We show that the
kinematics of the Large Magellanic Cloud can well be explained by our findings
for scale-free elliptic disks.Comment: AAS preprint format, 21 pages, 8 figures, accepted for publication in
The Astrophysical Journa
Effective Conformal Theory and the Flat-Space Limit of AdS
We develop the idea of an effective conformal theory describing the low-lying
spectrum of the dilatation operator in a CFT. Such an effective theory is
useful when the spectrum contains a hierarchy in the dimension of operators,
and a small parameter whose role is similar to that of 1/N in a large N gauge
theory. These criteria insure that there is a regime where the dilatation
operator is modified perturbatively. Global AdS is the natural framework for
perturbations of the dilatation operator respecting conformal invariance, much
as Minkowski space naturally describes Lorentz invariant perturbations of the
Hamiltonian. Assuming that the lowest-dimension single-trace operator is a
scalar, O, we consider the anomalous dimensions, gamma(n,l), of the
double-trace operators of the form O (del^2)^n (del)^l O. Purely from the CFT
we find that perturbative unitarity places a bound on these dimensions of
|gamma(n,l)|<4. Non-renormalizable AdS interactions lead to violations of the
bound at large values of n. We also consider the case that these interactions
are generated by integrating out a heavy scalar field in AdS. We show that the
presence of the heavy field "unitarizes" the growth in the anomalous
dimensions, and leads to a resonance-like behavior in gamma(n,l) when n is
close to the dimension of the CFT operator dual to the heavy field. Finally, we
demonstrate that bulk flat-space S-matrix elements can be extracted from the
large n behavior of the anomalous dimensions. This leads to a direct connection
between the spectrum of anomalous dimensions in d-dimensional CFTs and
flat-space S-matrix elements in d+1 dimensions. We comment on the emergence of
flat-space locality from the CFT perspective.Comment: 46 pages, 2 figures. v2: JHEP published versio
Testing Hydrodynamic Models of LMC X-4 with UV and X-ray Spectra
We compare the predictions of hydrodynamic models of the LMC X-4 X-ray binary
system with observations of UV P Cygni lines with the GHRS and STIS
spectrographs on the Hubble Space Telescope. The hydrodynamic model determines
density and velocity fields of the stellar wind, wind-compressed disk,
accretion stream, Keplerian accretion disk, and accretion disk wind. We use a
Monte Carlo code to determine the UV P Cygni line profiles by simulating the
radiative transfer of UV photons that originate on the star and are scattered
in the wind. The qualitative orbital variation predicted is similar to that
observed, although the model fails to reproduce the strong orbital asymmetry
(the observed absorption is strongest for phi>0.5). The model predicts a
mid-eclipse X-ray spectrum, due almost entirely to Compton scattering, with a
factor 4 less flux than observed with ASCA. We discuss how the model may need
to be altered to explain the spectral variability of the system.Comment: 11 figures, accepted by Ap
Holography from Conformal Field Theory
The locality of bulk physics at distances below the AdS length is one of the
remarkable aspects of AdS/CFT duality, and one of the least tested. It requires
that the AdS radius be large compared to the Planck length and the string
length. In the CFT this implies a large-N expansion and a gap in the spectum of
anomalous dimensions. We conjecture that the implication also runs in the other
direction, so that any CFT with a planar expansion and a large gap has a local
bulk dual. For an abstract CFT we formulate the consistency conditions, most
notably crossing symmetry, and show that the conjecture is true in a broad
range of CFT's, to first nontrivial order in 1/N^2: any CFT with a gap and a
planar expansion is generated via the AdS/CFT dictionary from a local bulk
interaction. We establish this result by a counting argument on each side, and
also investigate various properties of some explicit solutions.Comment: 49 pages. Minor corrections. Figure and references adde
Effective AdS/renormalized CFT
For an effective AdS theory, we present a simple prescription to compute the
renormalization of its dual boundary field theory. In particular, we define
anomalous dimension holographically as the dependence of the wave-function
renormalization factor on the radial cutoff in the Poincare patch of AdS. With
this definition, the anomalous dimensions of both single- and double- trace
operators are calculated. Three different dualities are considered with the
field theory being CFT, CFT with a double-trace deformation and spontaneously
broken CFT. For the second dual pair, we compute scaling corrections at the UV
and IR fixed points of the RG flow triggered by the double-trace deformation.
For the last case, we discuss whether our prescription is sensitive to the AdS
interior or equivalently, the IR physics of the dual field theory.Comment: 20 pages, 3 figure
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