10,128 research outputs found
Competing electronic orders on Kagome lattices at van Hove filling
The electronic orders in Hubbard models on a Kagome lattice at van Hove
filling are of intense current interest and debate. We study this issue using
the singular-mode functional renormalization group theory. We discover a rich
variety of electronic instabilities under short range interactions. With
increasing on-site repulsion , the system develops successively
ferromagnetism, intra unit-cell antiferromagnetism, and charge bond order. With
nearest-neighbor Coulomb interaction alone (U=0), the system develops
intra-unit-cell charge density wave order for small , s-wave
superconductivity for moderate , and the charge density wave order appears
again for even larger . With both and , we also find spin bond order
and chiral superconductivity in some particular
regimes of the phase diagram. We find that the s-wave superconductivity is a
result of charge density wave fluctuations and the squared logarithmic
divergence in the pairing susceptibility. On the other hand, the d-wave
superconductivity follows from bond order fluctuations that avoid the matrix
element effect. The phase diagram is vastly different from that in honeycomb
lattices because of the geometrical frustration in the Kagome lattice.Comment: 8 pages with 9 color figure
Progress on the treatment of neovascular glaucoma
Neovascular glaucoma(NVG)is a kind of intractable eye disease with complex etiology, strong destruction and poor effect on treatment. Extensive retinal ischemia and hypoxia is the main etiology, and the key of treatment is early diagnosis, active prevention and taking effective measures to prevent the production of vascular endothelial growth factor. According to the related literature over recent years, the authors will discuss pros and cons for medical, surgical and combined treatment in this review
First Abundance Measurement of Organic Molecules in the Atmosphere of HH 212 Protostellar Disk
HH 212 is one of the well-studied protostellar systems, showing the first
vertically resolved disk with a warm atmosphere around the central protostar.
Here we report a detection of 9 organic molecules (including newly detected
ketene, formic acid, deuterated acetonitrile, methyl formate, and ethanol) in
the disk atmosphere, confirming that the disk atmosphere is, for HH 212, the
chemically rich component, identified before at a lower resolution as a
"hot-corino". More importantly, we report the first systematic survey and
abundance measurement of organic molecules in the disk atmosphere within
40 au of the central protostar. The relative abundances of these molecules are
similar to those in the hot corinos around other protostars and in Comet
Lovejoy. These molecules can be either (i) originally formed on icy grains and
then desorbed into gas phase or (ii) quickly formed in the gas phase using
simpler species ejected from the dust mantles. The abundances and spatial
distributions of the molecules provide strong constraints on models of their
formation and transport in star formation. These molecules are expected to form
even more complex organic molecules needed for life and deeper observations are
needed to find them.Comment: 12 pages, 4 figure
CW-pumped telecom band polarization entangled photon pair generation in a Sagnac interferometer
A polarization entangled photon pair source is widely used in many quantum
information processing applications such as teleportation, quantum swapping,
quantum computation and high precision quantum metrology. Here, we report on
the generation of a continuous-wave pumped degenerated 1550 nm polarization
entangled photon pair source at telecom wavelength using a type-II
phase-matched periodically poled KTiOPO4 crystal in a Sagnac interferometer.
Hong-Ou-Mandel-type interference measurement shows the photon bandwidth of 2.4
nm. High quality of entanglement is verified by various kinds of measurements,
for example two-photon interference fringes, Bell inequality and quantum states
tomography. The wavelength of photons can be tuned over a broad range by
changing the temperature of crystal or pump power without losing the quality of
entanglement. This source will be useful for building up long-distance quantum
networks
Next-to-leading order QCD corrections to a heavy resonance production and decay into top quark pair at the LHC
We present a complete next-to-leading order (NLO) QCD calculation to a heavy
resonance production and decay into a top quark pair at the LHC, where the
resonance could be either a Randall-Sundrum (RS) Kaluza-Klein (KK) graviton
or an extra gauge boson . The complete NLO QCD corrections can enhance the
total cross sections by about and for the and
the , respectively, depending on the resonance mass. We also explore in
detail the NLO corrections to the polar angle distributions of the top quark,
and our results show that the shapes of the NLO distributions can be different
from the leading order (LO) ones for the KK graviton. Moreover, we study the
NLO corrections to the spin correlations of the top quark pair production via
the above process, and find that the corrections are small.Comment: Published version in PR
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