93 research outputs found
Collective flow in 2.76 A TeV and 5.02 A TeV Pb+Pb collisions
In this paper, we study and predict flow observables in 2.76 A TeV and 5.02 A
TeV Pb +Pb collisions, using the iEBE-VISHNU hybrid model with TRENto and AMPT
initial conditions and with different forms of the QGP transport coefficients.
With properly chosen and tuned parameter sets, our model calculations can
nicely describe various flow observables in 2.76 A TeV Pb +Pb collisions, as
well as the measured flow harmonics of all charged hadrons in 5.02 A TeV Pb +Pb
collisions. We also predict other flow observables, including of
identified particles, event-by-event distributions, event-plane
correlations, (Normalized) Symmetric Cumulants, non-linear response
coefficients and -dependent factorization ratios, in 5.02 A TeV Pb+Pb
collisions. We find many of these observables remain approximately the same
values as the ones in 2.76 A TeV Pb+Pb collisions. Our theoretical studies and
predictions could shed light to the experimental investigations in the near
future.Comment: 17 pages, 11 figure
Correlations of flow harmonics in 2.76A TeV Pb--Pb collisions
Using the event-by-event viscous hydrodynamics VISH2+1 with MC-Glauber,
MC-KLN, and AMPT initial conditions, we investigate the correlations of flow
harmonics, including the symmetric cumulants , the normalized
symmetric cumulants , and the Pearson correlation coefficients
in 2.76A TeV Pb--Pb collisions. We find is sensitive to both initial conditions and the specific shear viscosity
. A comparison with the recent ALICE data show that our hydrodynamic
calculations can qualitatively describe the data of and
for various initial conditions, which demonstrate that ,
are correlated and , are anti-correlated. Meanwhile, the
predicted symmetric cumulants , , and reveal that and , and are correlated, and
are anti-correlated in most centrality classes. We also find and , which are insensitive to , are
mainly determined by corresponding and
correlators from the initial
state. In contrast, other and
correlators are influenced by both initial conditions and , which
illustrates the non-linear mode couplings in higher flow harmonics with .Comment: 10 pages, 7 figure
Investigating the correlations of flow harmonics in 2.76A TeV Pb--Pb collisions
This proceeding briefly summarizes our recent investigations on the
correlations of flow harmonics in 2.76A TeV Pb--Pb collisions with viscous
hydrodynamics {\tt VISH2+1}. We calculated both the symmetric cumulants
and the normalized symmetric cumulants , and
found and , and , and are
correlated, and , and are anti-correlated. We
also found are insensitive to the QGP viscosity, which are
mainly determined by the initial conditions.Comment: SQM2016 proceeding, 4pages, 2 figure
Experimental test of contextuality in quantum and classical systems
Contextuality is considered as an intrinsic signature of non-classicality,
and a crucial resource for achieving unique advantages of quantum information
processing. However, recently there have been debates on whether classical
fields may also demonstrate contextuality. Here we experimentally configure a
contextuality test for optical fields, adopting various definitions of
measurement events, and analyse how the definitions affect the emergence of
non-classical correlations. The heralded single photon state, a typical
non-classical light field, manifests contextuality in our setup, while
contextuality for classical coherent fields strongly depends on the specific
definition of measurement events which is equivalent to filtering the
non-classical component of the input state. Our results highlight the
importance of definition of measurement events to demonstrate contextuality,
and link the contextual correlations to non-classicality defined by
quasi-probabilities in phase space.Comment: 17 pages, 7 figure
Hydrodynamic Collectivity in Proton--Proton Collisions at 13 TeV
In this paper, we investigate the hydrodynamic collectivity in proton--proton
(pp) collisions at 13 TeV, using iEBE-VISHNU hybrid model with HIJING initial
conditions. With properly tuned parameters, our model simulations can
remarkably describe all the measured 2-particle correlations, including
integrated and differential elliptic flow coefficients for all charged and
identified hadrons (, ). However, our model calculations show
positive 4-particle cumulant in high multiplicity pp collisions,
and can not reproduce the negative measured in experiment. Further
investigations on the HIJING initial conditions show that the fluctuations of
the second order anisotropy coefficient increases with the
increase of its mean value, which leads to a similar trend of the flow
fluctuations. For a simultaneous description of the 2- and 4- particle
cumulants within the hydrodynamic framework, it is required to have significant
improvements on initial condition for pp collisions, which is still lacking of
knowledge at the moment.Comment: 7 pages, 6 figures, published versio
Experimental quantification of coherence of a tunable quantum detector
Quantum coherence is a fundamental resource that quantum technologies exploit
to achieve performance beyond that of classical devices. A necessary
prerequisite to achieve this advantage is the ability of measurement devices to
detect coherence from the measurement statistics. Based on a recently developed
resource theory of quantum operations, here we quantify experimentally the
ability of a typical quantum-optical detector, the weak-field homodyne
detector, to detect coherence. We derive an improved algorithm for quantum
detector tomography and apply it to reconstruct the positive-operator-valued
measures (POVMs) of the detector in different configurations. The reconstructed
POVMs are then employed to evaluate how well the detector can detect coherence
using two computable measures. As the first experimental investigation of
quantum measurements from a resource theoretical perspective, our work sheds
new light on the rigorous evaluation of the performance of a quantum
measurement apparatus
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