178 research outputs found
The emergence of postcyclic prosody in loanword integration: Toneless Latinate adjectives in Serbo-Croatian
A case of exceptional assignment of prosody to loanwords is considered. In Serbo-Croatian, where in loanwords the original position of stress is generally preserved in some way, a small class of Latinate adjectives (e.g., "elementārna ‘elementary’ and p"ersonālna ‘personal’) become toneless and they display the postcyclic initial falling accent. An account of these data is proposed which combines a new approach to postcyclic prosody, which is shown to go hand in hand with syntactically opaque structures, and a new model of loanword integration, which views the loanword trajectory as lexicalisation. As a result, an enriched theory of both domains and their interaction arises to account for the data and shed some additional light on the position of loanwords in the architecture of the grammar/lexicon
Consistency Relations for the Conformal Mechanism
We systematically derive the consistency relations associated to the
non-linearly realized symmetries of theories with spontaneously broken
conformal symmetry but with a linearly-realized de Sitter subalgebra. These
identities relate (N+1)-point correlation functions with a soft external
Goldstone to N-point functions. These relations have direct implications for
the recently proposed conformal mechanism for generating density perturbations
in the early universe. We study the observational consequences, in particular a
novel one-loop contribution to the four-point function, relevant for the
stochastic scale-dependent bias and CMB mu-distortion.Comment: 34 pages, 3 figures. v2: minor changes, version appearing in JCA
Modeling Biased Tracers at the Field Level
In this paper we test the perturbative halo bias model at the field level.
The advantage of this approach is that any analysis can be done without sample
variance if the same initial conditions are used in simulations and
perturbation theory calculations. We write the bias expansion in terms of
modified bias operators in Eulerian space, designed such that the large bulk
flows are automatically resummed and not treated perturbatively. Using these
operators, the bias model accurately matches the Eulerian density of halos in
N-body simulations. The mean-square model error is close to the Poisson shot
noise for a wide range of halo masses and it is rather scale-independent, with
scale-dependent corrections becoming relevant at the nonlinear scale. In
contrast, for linear bias the mean-square model error can be higher than the
Poisson prediction by factors of up to a few on large scales, and it becomes
scale dependent already in the linear regime. We show that by weighting
simulated halos by their mass, the mean-square error of the model can be
further reduced by up to an order of magnitude, or by a factor of two when
including mass scatter. We also test the Standard Eulerian bias model
using the nonlinear matter field measured from simulations and show that it
leads to a larger and more scale-dependent model error than the bias expansion
based on perturbation theory. These results may be of particular relevance for
cosmological inference methods that use a likelihood of the biased tracer at
the field level, or for initial condition and BAO reconstruction that requires
a precise estimate of the large-scale potential from the biased tracer density.Comment: 61 pages, 27 figures. Minor edits and added references to match
published versio
Beyond the traditional Line-of-Sight approach of cosmological angular statistics
We present a new efficient method to compute the angular power spectra of
large-scale structure observables that circumvents the numerical integration
over Bessel functions, expanding on a recently proposed algorithm based on
FFTlog. This new approach has better convergence properties. The method is
explicitly implemented in the CLASS code for the case of number count
's (including redshift-space distortions, weak lensing, and all other
relativistic corrections) and cosmic shear 's. In both cases our
approach speeds up the calculation of the exact 's (without the Limber
approximation) by a factor of order 400 at a fixed precision target of 0.1%.Comment: 40 pages, 6 figures; v2: one reference adde
The Physical Squeezed Limit: Consistency Relations at Order q^2
In single-field models of inflation the effect of a long mode with momentum q
reduces to a diffeomorphism at zeroth and first order in q. This gives the
well-known consistency relations for the n-point functions. At order q^2 the
long mode has a physical effect on the short ones, since it induces curvature,
and we expect that this effect is the same as being in a curved FRW universe.
In this paper we verify this intuition in various examples of the three-point
function, whose behaviour at order q^2 can be written in terms of the power
spectrum in a curved universe. This gives a simple alternative understanding of
the level of non-Gaussianity in single-field models. Non-Gaussianity is always
parametrically enhanced when modes freeze at a physical scale k_{ph, f} shorter
than H: f_{NL} \sim (k_{ph, f}/H)^2.Comment: 18 pages, 1 figure. v2: small changes, JCAP published versio
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