46 research outputs found
Impact-based Nonlinear Acoustic Testing for Characterizing Distributed Damage in Concrete
Nonlinear acoustic testing techniques have shown great potential for identification of volumetric microcracking and early damage in diverse materials. In this paper, we compare the results of two impact-based techniques: Impact-based Nonlinear Resonant Acoustic Spectroscopy (INRAS) and Dynamic Acousto-Elastic Testing (IDAET) in monitoring damage in concrete due to Alkali-Silica Reaction (ASR) and freeze-thaw (FT) cycles. Using an impact hammer as the large-strain (strain ~ 10-6 -10-5 ) source (instead of a piezoelectric ceramic or a shaker used in conventional testing) allows testing large samples and enables field transportability. INRAS gives a global measure of sample nonlinearity while IDAET provides a local but comprehensive picture of material nonlinear properties. We propose two new data processing approaches for a single-impact INRAS that while being simpler, yields similar results to those from other analyses. We then introduce IDAET and show how to extract both classical and non-classical nonlinear parameters from the test results. INRAS (various analysis approaches) and IDAET are used to monitor a set of concrete samples undergoing accelerated ASR and FT cycles. Nonlinear parameters extracted from the two tests show good agreement; all exhibiting far more sensitivity to distributed FT damage than standard resonance frequency measurements
Fermion disorder operator at Gross-Neveu and deconfined quantum criticalities
The fermion disorder operator has been shown to reveal the entanglement
information in 1D Luttinger liquids and 2D free and interacting Fermi and
non-Fermi liquids emerging at quantum critical points(QCP). Here we study, by
means of large-scale quantum Monte Carlo simulation, the scaling behavior of
disorder operator in correlated Dirac systems. We first demonstrate the
logarithmic scaling behavior of the disorder operator at the Gross-Neveu (GN)
chiral Ising and Heisenberg QCPs, where consistent conformal field theory (CFT)
content of the GN-QCP in its coefficient is found. Then we study a 2D monopole
free deconfined quantum critical point (DQCP) realized between a quantum-spin
Hall insulator and a superconductor. Our data point to negative values of the
logarithmic coefficients such that the DQCP does not correspond to a unitary
CFT. Density matrix renormalization group calculations of the disorder operator
on a 1D DQCP model also detect emergent continuous symmetries.Comment: 16 pages, 18 figure
Many versus one: the disorder operator and entanglement entropy in fermionic quantum matter
Motivated by recent development of the concept of the disorder operator and
its relation with entanglement entropy in bosonic systems, here we show the
disorder operator successfully probes many aspects of quantum entanglement in
fermionic many-body systems. From both analytical and numerical computations in
free and interacting fermion systems in 1D and 2D, we find the disorder
operator and the entanglement entropy exhibit similar universal scaling
behavior, as a function of the boundary length of the subsystem, but with
subtle yet important differences. In 1D they both follow the scaling
behavior with the coefficient determined by the Luttinger parameter for
disorder operator, and the conformal central charge for entanglement entropy.
In 2D they both show the universal scaling behavior in free and
interacting Fermi liquid states, with the coefficients depending on the
geometry of the Fermi surfaces. However at a 2D quantum critical point with
non-Fermi-liquid state, extra symmetry information is needed in the design of
the disorder operator, so as to reveal the critical fluctuations as does the
entanglement entropy. Our results demonstrate the fermion disorder operator can
be used to probe quantum many-body entanglement related to global symmetry, and
provides new tools to explore the still largely unknown territory of highly
entangled fermion quantum matter in 2 or higher dimensions.Comment: 13 pages, 7 figures with 8 pages supplemental materia
Disorder Operator and R\'enyi Entanglement Entropy of Symmetric Mass Generation
In recent years a consensus has gradually been reached that the previously
proposed deconfined quantum critical point (DQCP) for spin-1/2 systems, an
archetypal example of quantum phase transition beyond the classic Landau's
paradigm, actually does not correspond to a true unitary conformal field theory
(CFT). In this work we carefully investigate another type of quantum phase
transition supposedly beyond the similar classic paradigm, the so called
``symmetric mass generation" (SMG) transition proposed in recent years. We
employ the sharp diagnosis including the scaling of disorder operator and
R\'enyi entanglement entropy in large-scale lattice model quantum Monte Carlo
simulations. Our results strongly suggest that the SMG transition is indeed an
unconventional quantum phase transition and it should correspond to a true
unitary CFT.Comment: 15 pages, 10 figure
The psychological science accelerator’s COVID-19 rapid-response dataset
In response to the COVID-19 pandemic, the Psychological Science Accelerator coordinated three large-scale psychological studies to examine the effects of loss-gain framing, cognitive reappraisals, and autonomy framing manipulations on behavioral intentions and affective measures. The data collected (April to October 2020) included specific measures for each experimental study, a general questionnaire examining health prevention behaviors and COVID-19 experience, geographical and cultural context characterization, and demographic information for each participant. Each participant started the study with the same general questions and then was randomized to complete either one longer experiment or two shorter experiments. Data were provided by 73,223 participants with varying completion rates. Participants completed the survey from 111 geopolitical regions in 44 unique languages/dialects. The anonymized dataset described here is provided in both raw and processed formats to facilitate re-use and further analyses. The dataset offers secondary analytic opportunities to explore coping, framing, and self-determination across a diverse, global sample obtained at the onset of the COVID-19 pandemic, which can be merged with other time-sampled or geographic data
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The Psychological Science Accelerator’s COVID-19 rapid-response dataset
In response to the COVID-19 pandemic, the Psychological Science Accelerator coordinated three large-scale psychological studies to examine the effects of loss-gain framing, cognitive reappraisals, and autonomy framing manipulations on behavioral intentions and affective measures. The data collected (April to October 2020) included specific measures for each experimental study, a general questionnaire examining health prevention behaviors and COVID-19 experience, geographical and cultural context characterization, and demographic information for each participant. Each participant started the study with the same general questions and then was randomized to complete either one longer experiment or two shorter experiments. Data were provided by 73,223 participants with varying completion rates. Participants completed the survey from 111 geopolitical regions in 44 unique languages/dialects. The anonymized dataset described here is provided in both raw and processed formats to facilitate re-use and further analyses. The dataset offers secondary analytic opportunities to explore coping, framing, and self-determination across a diverse, global sample obtained at the onset of the COVID-19 pandemic, which can be merged with other time-sampled or geographic data
A multi-country test of brief reappraisal interventions on emotions during the COVID-19 pandemic.
The COVID-19 pandemic has increased negative emotions and decreased positive emotions globally. Left unchecked, these emotional changes might have a wide array of adverse impacts. To reduce negative emotions and increase positive emotions, we tested the effectiveness of reappraisal, an emotion-regulation strategy that modifies how one thinks about a situation. Participants from 87 countries and regions (n = 21,644) were randomly assigned to one of two brief reappraisal interventions (reconstrual or repurposing) or one of two control conditions (active or passive). Results revealed that both reappraisal interventions (vesus both control conditions) consistently reduced negative emotions and increased positive emotions across different measures. Reconstrual and repurposing interventions had similar effects. Importantly, planned exploratory analyses indicated that reappraisal interventions did not reduce intentions to practice preventive health behaviours. The findings demonstrate the viability of creating scalable, low-cost interventions for use around the world