Search for: All records

This work proposes a class of differentially private mechanisms for linear queries, in par- ticular range queries, that leverages corre- lated input perturbation to simultaneously achieve unbiasedness, consistency, statisti- cal transparency, and control over utility re- quirements in terms of accuracy targets ex- pressed either in certain query margins or as implied by the hierarchical database struc- ture. The proposed Cascade Sampling al- gorithm instantiates the mechanism exactly and efficiently. Our theoretical and empir- ical analysis demonstrates that we achieve near-optimal utility, effectively compete with other methods, and retain all the favorable statistical properties discussed earlier. 

Abstract A hallmark of many unconventional superconductors is the presence of many-body interactions that give rise to broken-symmetry states intertwined with superconductivity. Recent resonant soft X-ray scattering experiments report commensurate 3a₀charge density wave order in infinite-layer nickelates, which has important implications regarding the universal interplay between charge order and superconductivity in both cuprates and nickelates. Here we present X-ray scattering and spectroscopy measurements on a series of NdNiO_2+xsamples, which reveal that the signatures of charge density wave order are absent in fully reduced, single-phase NdNiO₂. The 3a₀superlattice peak instead originates from a partially reduced impurity phase where excess apical oxygens form ordered rows with three-unit-cell periodicity. The absence of any observable charge density wave order in NdNiO₂highlights a crucial difference between the phase diagrams of cuprate and nickelate superconductors.