5,106 research outputs found
Nonlinear reconstruction
We present a direct approach to nonparametrically reconstruct the linear
density field from an observed nonlinear map. We solve for the unique
displacement potential consistent with the nonlinear density and positive
definite coordinate transformation using a multigrid algorithm. We show that we
recover the linear initial conditions up to the nonlinear scale
( for ) with minimal
computational cost. This reconstruction approach generalizes the linear
displacement theory to fully nonlinear fields, potentially substantially
expanding the baryon acoustic oscillations and redshift space distortions
information content of dense large scale structure surveys, including for
example SDSS main sample and 21cm intensity mapping initiatives.Comment: 7 pages, 7 figures, published versio
Isobaric Reconstruction of the Baryonic Acoustic Oscillation
In this paper, we report a significant recovery of the linear baryonic
acoustic oscillation (BAO) signature by applying the isobaric reconstruction
algorithm to the non-linear matter density field. Assuming only the
longitudinal component of the displacement being cosmologically relevant, this
algorithm iteratively solves the coordinate transform between the Lagrangian
and Eulerian frames without requiring any specific knowledge of the dynamics.
For dark matter field, it produces the non-linear displacement potential with
very high fidelity. The reconstruction error at the pixel level is within a few
percent, and is caused only by the emergence of the transverse component after
the shell-crossing. As it circumvents the strongest non-linearity of the
density evolution, the reconstructed field is well-described by linear theory
and immune from the bulk-flow smearing of the BAO signature. Therefore this
algorithm could significantly improve the measurement accuracy of the sound
horizon scale. For a perfect large-scale structure survey at redshift zero
without Poisson or instrumental noise, the fractional error is reduced by a
factor of 2.7, very close to the ideal limit with linear power spectrum and
Gaussian covariance matrix.Comment: 5 pages, 3 figures, accepted versio
Quench Dynamics of Topological Maximally-Entangled States
We investigate the quench dynamics of the one-particle entanglement spectra
(OPES) for systems with topologically nontrivial phases. By using dimerized
chains as an example, it is demonstrated that the evolution of OPES for the
quenched bi-partite systems is governed by an effective Hamiltonian which is
characterized by a pseudo spin in a time-dependent pseudo magnetic field
. The existence and evolution of the topological
maximally-entangled edge states are determined by the winding number of
in the -space. In particular, the maximally-entangled edge
states survive only if nontrivial Berry phases are induced by the winding of
. In the infinite time limit the equilibrium OPES can be
determined by an effective time-independent pseudo magnetic field
\vec{S}_{\mb{eff}}(k). Furthermore, when maximally-entangled edge states are
unstable, they are destroyed by quasiparticles within a characteristic
timescale in proportional to the system size.Comment: 5 pages, 3 figure
Complete NLO Operators in the Higgs Effective Field Theory
We enumerate the complete and independent sets of operators at the
next-to-leading order (NLO) in the Higgs effective field theory (HEFT), based
on the Young tensor technique on the Lorentz, gauge and flavor structures. The
operator-amplitude correspondence tells a type of operators forms the on-shell
amplitude basis, and for operators involving in Nambu-Goldstone bosons, the
amplitude basis is further reduced to the subspace satisfying the Adler's zero
condition in the soft momentum limit. Different from dynamical field, the
spurion should not enter into the Lorentz sector, instead it only plays a role
of forming the invariant together with other dynamical fields. With
these new treatments, for the first time we could obtain the 237 (8595)
operators for one (three) generation fermions, 295 (11307) with right-handed
neutrinos, and find there were 6 (9) terms of operators missing and many
redundant operators can be removed in the effective theory without (with)
right-handed neutrinos.Comment: 63 pages, 2 tables, revised version: operators in 4-component
notation, correct typo for countin
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