821 research outputs found
Fermionic symmetry-protected topological state in strained graphene
The low-energy physics of graphene is described by relativistic Dirac
fermions with spin and valley degrees of freedom. Mechanical strain can be used
to create a pseudo magnetic field pointing to opposite directions in the two
valleys. We study interacting electrons in graphene exposed to both an external
real magnetic field and a strain-induced pseudo magnetic field. For a certain
ratio between these two fields, it is proposed that a fermionic
symmetry-protected topological state can be realized. The state is
characterized in detail using model wave functions, Chern-Simons field theory,
and numerical calculations. Our paper suggests that graphene with artificial
gauge fields may host a rich set of topological states.Comment: 8 pages, 4 figure
Chiral Anomaly Beyond Fermionic Paradigm
Two-dimensional magnets have manifested themselves as promising candidates
for quantum devices. We here report that the edge and strain effects during the
device fabrication with two-dimensional honeycomb ferromagnets such as CrX
(X=Cl, I, Br) and CrXTe (X=Si, Ge) can be characterized by a
(1+1)-dimensional magnon chiral anomaly beyond the fermionic paradigm. In the
presence of zigzag edges, a pair of chiral bulk-edge magnon bands appear and
cause an imbalance of left- and right-chirality magnons when subjected to
nonuniform temperature or magnetic fields. In the presence of a uniaxial
strain, the bulk Dirac magnons are broken into chiral magnon pseudo-Landau
levels, resulting in a magnon chiral anomaly observable through a negative
strain-resistivity of the magnetic dipole and heat. Our work demonstrates a
chiral anomaly with (quasi)particles obeying non-fermionic statistics and will
be instructive in understanding anomalous magnon transport.Comment: 4.5 pages, 4 figure
Organo-Soluble Semi-Alicyclic Polyimides Derived from Substituted-Tetralin Dianhydrides and Aromatic Diamines: Synthesis, Characterization and Potential Applications as Alignment Layer for TFT-LCDs
Feluca : A two-stage graph coloring algorithm with color-centric paradigm on GPU
In this paper, we propose a two-stage high-performance graph coloring algorithm, called Feluca, aiming to address the above challenges. Feluca combines the recursion-based method with the sequential spread-based method. In the first stage, Feluca uses a recursive routine to color a majority of vertices in the graph. Then, it switches to the sequential spread method to color the remaining vertices in order to avoid the conflicts of the recursive algorithm. Moreover, the following techniques are proposed to further improve the graph coloring performance. i) A new method is proposed to eliminate the cycles in the graph; ii) a top-down scheme is developed to avoid the atomic operation originally required for color selection; and iii) a novel color-centric coloring paradigm is designed to improve the degree of parallelism for the sequential spread part. All these newly developed techniques, together with further GPU-specific optimizations such as coalesced memory access, comprise an efficient parallel graph coloring solution in Feluca. We have conducted extensive experiments on NVIDIA GPUs. The results show that Feluca can achieve 1.76 - 12.98x speedup over the state-of-the-art algorithms
Combined analysis of endometrial thickness and pattern in predicting outcome of in vitro fertilization and embryo transfer: a retrospective cohort study
<p>Abstract</p> <p>Objective</p> <p>To evaluate the combined effect of endometrial thickness and pattern on clinical outcome in patients undergoing in vitro fertilization/intracytoplasmic sperm injection and embryo transfer (IVF/ICSI-ET).</p> <p>Methods</p> <p>Cycles of IVF/ICSI-ET conducted between January 2003 and December 2008 at a university-based reproductive center were reviewed retrospectively. Endometrial ultrasonographic characteristics were recorded on the day of hCG administration. In the combined analysis, endometrial thickness groups (group 1: equal or <7 mm; group 2: 7-14 mm; group 3: >14 mm) were subdivided into two endometrial patterns (pattern A: triple-line; pattern B: no-triple line). Clinical pregnancy rate (CPR) and early miscarriage rate in different groups were analyzed.</p> <p>Results</p> <p>A total of 2896 cycles were reviewed. Clinical pregnancy rate (CPR) was 24.4% in group1-A. There were no second trimester pregnancies in group 1-B. Miscarriage rate in group 2-A was significantly lower compared to group 2-B (P < 0.01), although CPR did not show any significant differences between the groups. A no-triple line endometrial pattern with moderate endometrial thickness (7-14 mm) had a detrimental effect on pregnancy outcome, but not the occurrence of pregnancy. In group 3, there was no difference in CPR and miscarriage rates between the two patterns; adequate endometrial thickness (>14 mm) seemed to mitigate the detrimental impact (high miscarriage rate) of pattern B.</p> <p>Conclusion</p> <p>Combined analysis of endometrial thickness and pattern on the day of hCG administration was a better predictor of the outcome of IVF/ICSI-ET and may be more helpful for patient counseling than the separate analyses.</p
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