57 research outputs found
Survey of Social Bias in Vision-Language Models
In recent years, the rapid advancement of machine learning (ML) models,
particularly transformer-based pre-trained models, has revolutionized Natural
Language Processing (NLP) and Computer Vision (CV) fields. However, researchers
have discovered that these models can inadvertently capture and reinforce
social biases present in their training datasets, leading to potential social
harms, such as uneven resource allocation and unfair representation of specific
social groups. Addressing these biases and ensuring fairness in artificial
intelligence (AI) systems has become a critical concern in the ML community.
The recent introduction of pre-trained vision-and-language (VL) models in the
emerging multimodal field demands attention to the potential social biases
present in these models as well. Although VL models are susceptible to social
bias, there is a limited understanding compared to the extensive discussions on
bias in NLP and CV. This survey aims to provide researchers with a high-level
insight into the similarities and differences of social bias studies in
pre-trained models across NLP, CV, and VL. By examining these perspectives, the
survey aims to offer valuable guidelines on how to approach and mitigate social
bias in both unimodal and multimodal settings. The findings and recommendations
presented here can benefit the ML community, fostering the development of
fairer and non-biased AI models in various applications and research endeavors
Neutron spin resonance as a probe of superconducting gap anisotropy in partially detwinned electron underdoped NaFeCoAs
We use inelastic neutron scattering (INS) to study the spin excitations in
partially detwinned NaFeCoAs which has coexisting static
antiferromagnetic (AF) order and superconductivity ( K, K). In
previous INS work on a twinned sample, spin excitations form a dispersive sharp
resonance near meV and a broad dispersionless mode at
meV at the AF ordering wave vector and its
twinned domain . For partially detwinned
NaFeCoAs with the static AF order mostly occurring at , we still find a double resonance at both wave vectors with
similar intensity. Since characterizes the explicit breaking
of the spin rotational symmetry associated with the AF order, these results
indicate that the double resonance cannot be due to the static and fluctuating
AF orders, but originate from the superconducting gap anisotropy.Comment: 5 pages, 5 figures; PRB, 2015 (the correct final version is now used
Electronic nematic correlations in the stress free tetragonal state of BaFeNiAs
We use transport and neutron scattering to study electronic, structural, and
magnetic properties of the electron-doped BaFeNiAs iron
pnictides in the external stress free detwinned state. Using a specially
designed in-situ mechanical detwinning device, we demonstrate that the in-plane
resistivity anisotropy observed in the uniaxial strained tetragonal state of
BaFeNiAs below a temperature , previously identified as
a signature of the electronic nematic phase, is also present in the stress free
tetragonal phase below (). By carrying out neutron
scattering measurements on BaFeAs and BaFeNiAs,
we argue that the resistivity anisotropy in the stress free tetragonal state of
iron pnictides arises from the magnetoelastic coupling associated with
antiferromagnetic order. These results thus indicate that the local lattice
distortion and nematic spin correlations are responsible for the resistivity
anisotropy in the tetragonal state of iron pnictides.Comment: 5 pages, 4 figure
Effect of nematic order on the low-energy spin fluctuations in detwinned BaFeNiAs
The origin of nematic order remains one of the major debates in iron-based
superconductors. In theories based on spin nematicity, one major prediction is
that the spin-spin correlation length at (0,) should decrease with
decreasing temperature below the structural transition temperature . Here
we report inelastic neutron scattering studies on the low-energy spin
fluctuations in BaFeNiAs under uniaxial pressure. Both
intensity and spin-spin correlation start to show anisotropic behavior at high
temperature, while the reduction of the spin-spin correlation length at
(0,) happens just below , suggesting strong effect of nematic order
on low-energy spin fluctuations. Our results favor the idea that treats the
spin degree of freedom as the driving force of the electronic nematic order.Comment: 5 pages, 4 figure
Impact of Uniaxial Pressure on Structural and Magnetic Phase Transitions in Electron-Doped Iron Pnictides
We use neutron resonance spin echo and Larmor diffraction to study the effect
of uniaxial pressure on the tetragonal-to-orthorhombic structural () and
antiferromagnetic (AF) phase transitions in iron pnictides
BaFeNiAs (), SrFeNiAs,
and BaFe(AsP). In antiferromagnetically ordered
BaFeNiAs and SrFeNiAs with and
(), a uniaxial pressure necessary to detwin the sample also
increases , smears out the structural transition, and induces an
orthorhombic lattice distortion at all temperatures. By comparing temperature
and doping dependence of the pressure induced lattice parameter changes with
the elastoresistance and nematic susceptibility obtained from transport and
ultrasonic measurements, we conclude that the in-plane resistivity anisotropy
found in the paramagnetic state of electron underdoped iron pnictides depends
sensitively on the nature of the magnetic phase transition and a strong
coupling between the uniaxial pressure induced lattice distortion and
electronic nematic susceptibility.Comment: 18 pages, 15 figure
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