3,824 research outputs found
Parity-time electromagnetic diodes in a two-dimensional nonreciprocal photonic crystal
We propose a kind of electromagnetic (EM) diode based on a two-dimensional nonreciprocal gyrotropic photonic crystal. This
periodic microstructure has separately broken symmetries in both parity
(P) and time-reversal (T) but obeys parity-time (PT) symmetry. This
kind of diode could support bulk one-way propagating modes either for
group velocity or phase velocity with various types of negative and
positive refraction. This symmetry-broken system could be a platform to
realize abnormal photoelectronic devices, and it may be analogous to an
electron counterpart with one-way features
Triaqua(2,2′-bipyridine N,N′-dioxide-κ2 O,O′)(5-nitrobenzene-1,3-dicarboxylato-κO 1)zinc(II)
In the title compound, [Zn(C8H3NO6)(C10H8N2O2)(H2O)3], the ZnII ion is coordinated in a distorted octahedral geometry by three water molecules, one O atom from a 5-nitrobenzene-1,3-dicarboxylate ligand and two O atoms from a chelating 2,2′-bipyridine N,N′-dioxide ligand. An extensive network of O—H⋯O hydrogen bonds is formed between the water molecules and the carboxylate groups. C—H⋯O interactions are also present
Light-cone Sum Rule Analysis of Semileptonic Decays
In this work, we analyze the semileptonic decay processes of in the light-cone sum rule approach. In the calculation of the form
factors of baryon transition matrix element, the light-cone
distribution amplitudes of which are obtained from QCD sum rule in
the heavy quark effective field theory framework are used. With the calculation
of the six form factors of transition matrix element,
the differential decay widths of and absolute branching fractions are
obtained. Additionally the ratio of is
obtained. These results are in accordance with the newest experimental result
and other theoretical calculations and predictions.Comment: 10 pages,6 figure
One-way cloak based on nonreciprocal photonic crystal
We propose a physical concept of non-reciprocal transformation optics, by which a one-way invisible cloak is designed. The one-way invisible cloak is made of a coordinate-transformed nonreciprocal photonic crystal, showing a perfect cloaking for wave incident from one direction but acting as a perfect reflector for wave from the counter direction. The proposed design shows a high promise of applications in military, as protecting the own information to be detected but efficiently grabbing the information from the “enemy” side
Mesoscopic Kondo screening effect in a single-electron transistor embedded in a metallic ring
We study the Kondo screening effect generated by a single-electron transistor
or quantum dot embedded in a small metallic ring. When the ring circumference
becomes comparable to the fundamental length scale associated with the {\it bulk} Kondo tempe the Kondo resonance is
strongly affected, depending on the total number of electrons ({\it modulo} 4)
and magnetic flux threading the ring. The resulting Kondo-assisted persistent
currents are also calculated in both Kondo and mixed valence regimes, and the
maximum values are found in the crossover region.Comment: 4 pages, Revtex, 6 figures, more references are include
Valence bond spin liquid state in two-dimensional frustrated spin-1/2 Heisenberg antiferromagnets
Fermionic valence bond approach in terms of SU(4) representation is proposed
to describe the frustrated Heisenberg antiferromagnetic (AF)
model on a {\it bipartite} square lattice. A uniform mean field solution
without breaking the translational and rotational symmetries describes a
valence bond spin liquid state, interpolating the two different AF ordered
states in the large and large limits, respectively. This novel
spin liquid state is gapless with the vanishing density of states at the Fermi
nodal points. Moreover, a sharp resonance peak in the dynamic structure factor
is predicted for momenta and in the strongly
frustrated limit , which can be checked by neutron
scattering experiment.Comment: Revtex file, 4 pages, 4 figure
Tunable Unidirectional Sound Propagation through a Sonic-Crystal-Based Acoustic Diode
Nonreciprocal wave propagation typically requires strong nonlinear materials to break time reversal symmetry. Here, we utilized a
sonic-crystal-based acoustic diode that had broken spatial inversion
symmetry and experimentally realized sound unidirectional transmission
in this acoustic diode. These novel phenomena are attributed to
different mode transitions as well as their associated different energy
conversion efficiencies among different diffraction orders at two sides
of the diode. This nonreciprocal sound transmission could be
systematically controlled by simply mechanically rotating the square
rods of the sonic crystal. Different from nonreciprocity due to the
nonlinear acoustic effect and broken time reversal symmetry, this new
model leads to a one-way effect with higher efficiency, broader
bandwidth, and much less power consumption, showing promising
applications in various sound devices
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