235 research outputs found
Antiferromagnetic ordering induced by paramagnetic depairing in unconventional superconductors
Antiferromagnetic (AFM) (or spin-density wave) quantum critical fluctuation
enhanced just below H_c2(0) have been often observed in d-wave superconductors
with a strong Pauli paramagnetic depairing (PD) including CeCoIn_5. It is shown
here that such a tendency of field-induced AFM ordering is a consequence of
strong PD and should appear particularly in superconductors with a gap node
along the AFM modulation. Two phenomena seen in CeCoIn_5, the anomalous vortex
lattice form factor and the AFM order in the Fulde-Ferrell-Larkin-Ovchinnikov
state, are explained based on this peculiar PD effect.Comment: 4 pages, 3 figures Title and text were changed. References are added.
Resubmitted versio
Equal-Spin Pairing State of Superfluid He in Aerogel
The equal-spin pairing (ESP) state, the so-called A-like phase, of superfluid
He in aerogels is studied theoretically in the Ginzburg-Landau (GL) region
by examining thermodynamics, and the resulting equilibrium phase diagram is
mapped out. We find that, among the ABM, planar, and robust pairing states, the
ABM state with presumably quasi long-ranged superfluid order is the best
candidate of the A-like phase with a strange lowering of the polycritical point
(PCP) observed experimentally.Comment: 4 pages, 1 figure, one reference added, accepted for publication in
Phys. Rev.
Bayesian Nonparametric Learning of Cloth Models for Real-time State Estimation
Robotic solutions to clothing assistance can significantly improve quality of life for the elderly and disabled. Real-time estimation of the human-cloth relationship is crucial for efficient learning of motor skills for robotic clothing assistance. The major challenge involved is cloth-state estimation due to inherent nonrigidity and occlusion. In this study, we present a novel framework for real-time estimation of the cloth state using a low-cost depth sensor, making it suitable for a feasible social implementation. The framework relies on the hypothesis that clothing articles are constrained to a low-dimensional latent manifold during clothing tasks. We propose the use of manifold relevance determination (MRD) to learn an offline cloth model that can be used to perform informed cloth-state estimation in real time. The cloth model is trained using observations from a motion capture system and depth sensor. MRD provides a principled probabilistic framework for inferring the accurate motion-capture state when only the noisy depth sensor feature state is available in real time. The experimental results demonstrate that our framework is capable of learning consistent task-specific latent features using few data samples and has the ability to generalize to unseen environmental settings. We further present several factors that affect the predictive performance of the learned cloth-state model
Complete Cross-triplet Loss in Label Space for Audio-visual Cross-modal Retrieval
The heterogeneity gap problem is the main challenge in cross-modal retrieval.
Because cross-modal data (e.g. audiovisual) have different distributions and
representations that cannot be directly compared. To bridge the gap between
audiovisual modalities, we learn a common subspace for them by utilizing the
intrinsic correlation in the natural synchronization of audio-visual data with
the aid of annotated labels. TNN-CCCA is the best audio-visual cross-modal
retrieval (AV-CMR) model so far, but the model training is sensitive to hard
negative samples when learning common subspace by applying triplet loss to
predict the relative distance between inputs. In this paper, to reduce the
interference of hard negative samples in representation learning, we propose a
new AV-CMR model to optimize semantic features by directly predicting labels
and then measuring the intrinsic correlation between audio-visual data using
complete cross-triple loss. In particular, our model projects audio-visual
features into label space by minimizing the distance between predicted label
features after feature projection and ground label representations. Moreover,
we adopt complete cross-triplet loss to optimize the predicted label features
by leveraging the relationship between all possible similarity and
dissimilarity semantic information across modalities. The extensive
experimental results on two audio-visual double-checked datasets have shown an
improvement of approximately 2.1% in terms of average MAP over the current
state-of-the-art method TNN-CCCA for the AV-CMR task, which indicates the
effectiveness of our proposed model.Comment: 9 pages, 5 figures, 3 tables, accepted by IEEE ISM 202
ネット イケン カツヨウ ノ タメ ノ カイセキ オヨビ ブンルイ ギジュツ 二 カンスル ケンキュウ
this is the author’s version of a work that was accepted for publication in Knowledge-Based Systems. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in PUBLICATION, [VOL51, ( October 2013)] DOI:10.1016/j.knosys.2013.06.02
Fluctuation and Order of Antiferromagnetism induced by Paramagnetic Pair-Breaking in Superconducting Vortex Lattice
Effects of the strong Pauli-paramagnetic pair-breaking (PPB) on the vortex
lattice in d-wave superconductors are theoretically studied by putting emphasis
on consequences of the PPB-induced antiferromagnetic (AFM) ordering in the
spatial modulation in the vortex lattice. It is shown that the PPB-induced AFM
fluctuation in the superconducting state leads to an enhancement of the vortex
lattice form factor which is a measure of spatial variations of the internal
magnetic field and that the enhancement becomes more remarkable as an AFM
instability is approached. It is also demonstrated that the PPB-induced AFM
ordering is assisted by the vortex-lattice modulation, and thus, that the
resulting AFM order is spatially modulated, while it is not localized in the
vortex cores but coexistent with the nonvanishing superconducting order
parameter. These results are discussed in connection with two phenomena
observed in CeCoIn5, the anomalous field dependence of the vortex lattice form
factor and the AFM order appearing inside the high-field and low-temperature
superconducting phase.Comment: 26 pages, 13 figure
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