6,806 research outputs found
Measurement of the pairwise kinematic Sunyaev-Zeldovich effect with Planck and BOSS data
We present a new measurement of the kinetic Sunyaev-Zeldovich effect (kSZ)
using Planck cosmic microwave background (CMB) and Baryon Oscillation
Spectroscopic Survey (BOSS) data. Using the `LowZ North/South' galaxy catalogue
from BOSS DR12, and the group catalogue from BOSS DR13, we evaluate the mean
pairwise kSZ temperature associated with BOSS galaxies. We construct a `Central
Galaxies Catalogue' (CGC) which consists of isolated galaxies from the original
BOSS data set, and apply the aperture photometry (AP) filter to suppress the
primary CMB contribution. By constructing a halo model to fit the pairwise kSZ
function, we constrain the mean optical depth to be
for `LowZ North CGC',
for `LowZ South CGC', and
for `DR13 Group'. In
addition, we vary the radius of the AP filter and find that the AP size of
gives the maximum detection for . We also
investigate the dependence of the signal with halo mass and find
and
for `DR13 Group' with halo
mass restricted to, respectively, less and greater than its median halo mass,
. For the `LowZ North CGC' sample restricted
to there is no detection of
the kSZ signal because these high mass halos are associated with the
high-redshift galaxies of the LowZ North catalogue, which have limited
contribution to the pairwise kSZ signals.Comment: 11 pages, 11 figures, 2 table
Prethermal quasiconserved observables in Floquet quantum systems
Prethermalization, by introducing emergent quasiconserved observables, plays
a crucial role in protecting Floquet many-body phases over exponentially long
time, while the ultimate fate of such quasiconserved operators can signal
thermalization to infinite temperature. To elucidate the properties of
prethermal quasiconservation in many-body Floquet systems, here we
systematically analyze infinite temperature correlations between observables.
We numerically show that the late-time behavior of the autocorrelations
unambiguously distinguishes quasiconserved observables from non-conserved ones,
allowing to single out a set of linearly-independent quasiconserved
observables. By investigating two Floquet spin models, we identify two
different mechanism underlying the quasi-conservation law. First, we
numerically verify energy quasiconservation when the driving frequency is
large, so that the system dynamics is approximately described by a static
prethermal Hamiltonian. More interestingly, under moderate driving frequency,
another quasiconserved observable can still persist if the Floquet driving
contains a large global rotation. We show theoretically how to calculate this
conserved observable and provide numerical verification. Having systematically
identified all quasiconserved observables, we can finally investigate their
behavior in the infinite-time limit and thermodynamic limit, using
autocorrelations obtained from both numerical simulation and experiments in
solid state nuclear magnetic resonance systems.Comment: 12 pages, 9 figures. arXiv admin note: substantial text overlap with
arXiv:1912.0579
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