5,134 research outputs found
Optimized Decimation of Tensor Networks with Super-orthogonalization for Two-Dimensional Quantum Lattice Models
A novel algorithm based on the optimized decimation of tensor networks with
super-orthogonalization (ODTNS) that can be applied to simulate efficiently and
accurately not only the thermodynamic but also the ground state properties of
two-dimensional (2D) quantum lattice models is proposed. By transforming the 2D
quantum model into a three-dimensional (3D) closed tensor network (TN)
comprised of the tensor product density operator and a 3D brick-wall TN, the
free energy of the system can be calculated with the imaginary time evolution,
in which the network Tucker decomposition is suggested for the first time to
obtain the optimal lower-dimensional approximation on the bond space by
transforming the TN into a super-orthogonal form. The efficiency and accuracy
of this algorithm are testified, which are fairly comparable with the quantum
Monte Carlo calculations. Besides, the present ODTNS scheme can also be
applicable to the 2D frustrated quantum spin models with nice efficiency
OVSNet : Towards One-Pass Real-Time Video Object Segmentation
Video object segmentation aims at accurately segmenting the target object
regions across consecutive frames. It is technically challenging for coping
with complicated factors (e.g., shape deformations, occlusion and out of the
lens). Recent approaches have largely solved them by using backforth
re-identification and bi-directional mask propagation. However, their methods
are extremely slow and only support offline inference, which in principle
cannot be applied in real time. Motivated by this observation, we propose a
efficient detection-based paradigm for video object segmentation. We propose an
unified One-Pass Video Segmentation framework (OVS-Net) for modeling
spatial-temporal representation in a unified pipeline, which seamlessly
integrates object detection, object segmentation, and object re-identification.
The proposed framework lends itself to one-pass inference that effectively and
efficiently performs video object segmentation. Moreover, we propose a
maskguided attention module for modeling the multi-scale object boundary and
multi-level feature fusion. Experiments on the challenging DAVIS 2017
demonstrate the effectiveness of the proposed framework with comparable
performance to the state-of-the-art, and the great efficiency about 11.5 FPS
towards pioneering real-time work to our knowledge, more than 5 times faster
than other state-of-the-art methods.Comment: 10 pages, 6 figure
Development of a Transferable Reactive Force Field of P/H Systems: Application to the Chemical and Mechanical Properties of Phosphorene
ReaxFF provides a method to model reactive chemical systems in large-scale
molecular dynamics simulations. Here, we developed ReaxFF parameters for
phosphorus and hydrogen to give a good description of the chemical and
mechanical properties of pristine and defected black phosphorene. ReaxFF for
P/H is transferable to a wide range of phosphorus and hydrogen containing
systems including bulk black phosphorus, blue phosphorene, edge-hydrogenated
phosphorene, phosphorus clusters and phosphorus hydride molecules. The
potential parameters were obtained by conducting unbiased global optimization
with respect to a set of reference data generated by extensive ab initio
calculations. We extend ReaxFF by adding a 60{\deg} correction term which
significantly improves the description of phosphorus clusters. Emphasis has
been put on obtaining a good description of mechanical response of black
phosphorene with different types of defects. Compared to nonreactive SW
potential [1], ReaxFF for P/H systems provides a huge improvement in describing
the mechanical properties the pristine and defected black phosphorene and the
thermal stability of phosphorene nanotubes. A counterintuitive phenomenon is
observed that single vacancies weaken the black phosphorene more than double
vacancies with higher formation energy. Our results also show that mechanical
response of black phosphorene is more sensitive to defects for the zigzag
direction than for the armchair direction. Since ReaxFF allows straightforward
extensions to the heterogeneous systems, such as oxides, nitrides, ReaxFF
parameters for P/H systems build a solid foundation for the reactive force
field description of heterogeneous P systems, including P-containing 2D van der
Waals heterostructures, oxides, etc
μ-2,2′-(Azinodimethylene)dibenzeneÂsulfonato-bisÂ[heptaÂaquaÂeuropium(III)] bisÂ[2,2′-(azinoÂdimethylene)dibenzeneÂsulfonate] decaÂhydrate
In the title compound, [Eu2(C14H10N2O6S2)(H2O)14](C14H10N2O6S2)2·10H2O, the complete bimetallic cation is generated by crystallographic inversion symmetry. The Eu atom adopts a distorted dodecaÂhedral coordination arising from one O-bonded 2,2′-azinodibenzeneÂsulfonate ligand and seven water molÂecules. In the crystal structure, the components are linked by multiple O—H⋯O and O—H⋯N hydrogen bonds
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