273 research outputs found
FaiREE: Fair Classification with Finite-Sample and Distribution-Free Guarantee
Algorithmic fairness plays an increasingly critical role in machine learning
research. Several group fairness notions and algorithms have been proposed.
However, the fairness guarantee of existing fair classification methods mainly
depends on specific data distributional assumptions, often requiring large
sample sizes, and fairness could be violated when there is a modest number of
samples, which is often the case in practice. In this paper, we propose FaiREE,
a fair classification algorithm that can satisfy group fairness constraints
with finite-sample and distribution-free theoretical guarantees. FaiREE can be
adapted to satisfy various group fairness notions (e.g., Equality of
Opportunity, Equalized Odds, Demographic Parity, etc.) and achieve the optimal
accuracy. These theoretical guarantees are further supported by experiments on
both synthetic and real data. FaiREE is shown to have favorable performance
over state-of-the-art algorithms.Comment: 45 pages, 9 figure
Anderson-Bernoulli Localization On 2d And 3d Lattice
The Anderson model describes the behaviour of electrons inside a piece of metal with uniform impurity.The Anderson-Bernoulli model is a special case of the Anderson model where the potential has Bernoulli distribution. We consider Anderson-Bernoulli localization on d dimensional lattice for d=2,3. For d=2, we prove that, if the potential has symmetric Bernoulli distribution and the disorder is large, then localization happens outside a small neighborhood of finitely many energies. For d=3, we prove that localization happens at the bottom of the spectrum
Spin gap and magnetic resonance in superconducting BaFeNiAs
We use neutron spectroscopy to determine the nature of the magnetic
excitations in superconducting BaFeNiAs ( K).
Above the excitations are gapless and centered at the commensurate
antiferromagnetic wave vector of the parent compound, while the intensity
exhibits a sinusoidal modulation along the c-axis. As the superconducting state
is entered a spin gap gradually opens, whose magnitude tracks the
-dependence of the superconducting gap observed by angle resolved
photoemission. Both the spin gap and magnetic resonance energies are
temperature \textit{and} wave vector dependent, but their ratio is the same
within uncertainties. These results suggest that the spin resonance is a
singlet-triplet excitation related to electron pairing and superconductivity.Comment: 4 pages, 4 figure
Effect of Zn doping on magnetic order and superconductivity in LaFeAsO
We report Zn-doping effect in the parent and F-doped LaFeAsO oxy-arsenides.
Slight Zn doping in LaFeZnAsO drastically suppresses the
resistivity anomaly around 150 K associated with the antiferromagnetic (AFM)
spin density wave (SDW) in the parent compound. The measurements of magnetic
susceptibility and thermopower confirm further the effect of Zn doping on AFM
order. Meanwhile Zn doping does not affect or even enhances the of
LaFeZnAsOF, in contrast to the effect of Zn
doping in high- cuprates. We found that the solubility of Zn content ()
is limited to less than 0.1 in both systems and further Zn doping (i.e.,
0.1) causes phase separation. Our study clearly indicates that the
non-magnetic impurity of Zn ions doped in the FeAs layers
affects selectively the AFM order, and superconductivity remains robust against
the Zn doping in the F-doped superconductors.Comment: 7 figures, 13 pages; revised version with more dat
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