50 research outputs found
Towards Equipping Transformer with the Ability of Systematic Compositionality
One of the key factors in language productivity and human cognition is the
ability of systematic compositionality, which refers to understanding composed
unseen examples of seen primitives. However, recent evidence reveals that the
Transformers have difficulty generalizing the composed context based on the
seen primitives. To this end, we take the first step to propose a
compositionality-aware Transformer called CAT and two novel pre-training tasks
to facilitate systematic compositionality. We tentatively provide a successful
implementation of a multi-layer CAT on the basis of the especially popular
BERT. The experimental results demonstrate that CAT outperforms baselines on
compositionality-aware tasks with minimal impact on the effectiveness on
standardized language understanding tasks.Comment: Accepted to AAAI 2024. Paper with appendi
Semiconducting transport in PbCu(PO)O sintered from PbSO and CuP
The very recent claim on the discovery of ambient-pressure room-temperature
superconductivity in modified lead-apatite has immediately excited sensational
attention in the entire society, which is fabricated by sintering lanarkite
(Pb2SO5) and copper(I) phosphide (CuP). To verify this exciting claim, we
have successfully synthesized PbSO, CuP, and finally the modified
lead-apatite PbCu(PO)O. Detailed electrical transport and
magnetic properties of these compounds were systematically analyzed. It turns
out that PbSO is a highly insulating diamagnet with a room-temperature
resistivity of ~7.18x10 Ohm.cm and CuP is a paramagnetic metal with a
room-temperature resistivity of ~5.22x10 Ohm.cm. In contrast to the
claimed superconductivity, the resulting PbCu(PO)O
compound sintered from PbSO and CuP exhibits semiconductor-like
transport behavior with a large room-temperature resistivity of ~1.94x10
Ohm.cm although our compound shows greatly consistent x-ray diffraction
spectrum with the previously reported structure data. In addition, when a
pressed PbCu(PO)O pellet is located on top of a commercial
NdFeB magnet at room temperature, no repulsion could be felt and no
magnetic levitation was observed either. These results imply that the claim of
a room-temperature superconductor in modified lead-apatite may need more
careful re-examination, especially for the electrical transport properties.Comment: 12 pages, 13 figure
Observation of the Anomalous Hall Effect in a Collinear Antiferromagnet
Time-reversal symmetry breaking is the basic physics concept underpinning
many magnetic topological phenomena such as the anomalous Hall effect (AHE) and
its quantized variant. The AHE has been primarily accompanied by a
ferromagnetic dipole moment, which hinders the topological quantum states and
limits data density in memory devices, or by a delicate noncollinear magnetic
order with strong spin decoherence, both limiting their applicability. A
potential breakthrough is the recent theoretical prediction of the AHE arising
from collinear antiferromagnetism in an anisotropic crystal environment. This
new mechanism does not require magnetic dipolar or noncollinear fields.
However, it has not been experimentally observed to date. Here we demonstrate
this unconventional mechanism by measuring the AHE in an epilayer of a rutile
collinear antiferromagnet RuO. The observed anomalous Hall conductivity is
large, exceeding 300 S/cm, and is in agreement with the Berry phase topological
transport contribution. Our results open a new unexplored chapter of
time-reversal symmetry breaking phenomena in the abundant class of collinear
antiferromagnetic materials.Comment: 33 pages, 14 figures, 2 table
Publisher Correction: An anomalous Hall effect in altermagnetic ruthenium dioxide
In the version of this article initially published, square brackets and parentheses were incorrect in Fig. 1g and throughout Fig. 2 (excepting lower labels in Fig. 2d–f). Further, in the second paragraph of the “Consistency with theoretical prediction” subsection of the main article, in the text now reading “the reorientation-field scale, namely, HC = (H2 AE − H2 d) /Hd,” the term “H2 AE” wasn’t shown as squared. The changes have been made in the HTML and PDF versions of the article
Convergence rate for the moving least-squares learning with dependent sampling
Abstract We consider the moving least-squares (MLS) method by the regression learning framework under the assumption that the sampling process satisfies the α-mixing condition. We conduct the rigorous error analysis by using the probability inequalities for the dependent samples in the error estimates. When the dependent samples satisfy an exponential α-mixing, we derive the satisfactory learning rate and error bound of the algorithm