13,653 research outputs found
Plasmonic Nano-Rotamers with Programmable Polarization-Resolved Coloration
3D-shaped artificial Mg nano-rotamers with a programmable dihedral angle between two plasmonic arms, designed to exhibit both programmable linear and circular polarization properties, are presented. The nanoscale physical shadow growth technique offers precise control over the angular alignment in these nanostructures with 1° angular precision, thus controlling their symmetry from achiral C2v and C2h to chiral C2. As a result, they give rise to a wide range of polarization-resolved coloration, spanning from invisible to visible colors with 46% transmission contrast for linear polarization while exhibiting 0.08 g-factor in visible for circular polarization. These nano-rotamers hold great potential for various applications in adaptive photonic filters, memory, and anticounterfeiting devices, benefiting from their tunable plasmonic properties
The anomalous U(1) global symmetry and flavors from an SU(5) x SU(5) GUT in orbifold compactification
In string compactifications, frequently there appears the anomalous U(1)
gauge symmetry which belonged to E8E8 of the heterotic string. This
anomalous U(1) gauge boson obtains mass at the compactification scale, just
below GeV, by absorbing one pseudoscalar (corresponding to the
model-independent axion) from the second rank anti-symmetric tensor field
.
Below the compactification scale, there results a global symmetry U(1) whose charge is the original gauge U(1) charge. This is
the most natural global symmetry, realizing the "invisible" axion. This global
symmetry U(1) is suitable for a flavor symmetry. In the simplest
compactification model with the flipped SU(5) grand unification, we calculate
all the low energy parameters in terms of the vacuum expectation values of the
standard model singlets.Comment: 18 pages, 4 figur
Electrical conductivity and electromagnetic interference shielding of multiwalled carbon nanotube composites containing Fe catalyst
Thin and flexible composite films of raw or purified multiwalled carbon nanotube (MWCNT) with various mass fractions and poly(methylmethacrylate) (PMMA) were synthesized for electromagnetic interference (EMI) shielding material. From scanning electron microscopy and high-resolution transmission electron microscopy photographs, we observed the formation of a conducting network through MWCNTs in an insulating PMMA matrix and the existence of an Fe catalyst in MWCNTs. The dc conductivity (sigma(dc)) of the systems increased with increasing MWCNT mass fraction, showing typical percolation behavior. The measured EMI shielding efficiency (SE) of MWCNT-PMMA composites by using the extended ASTM D4935-99 method (50 MHz-13.5 GHz) increased with increasing MWCNT mass fraction as sigma(dc). The highest EMI SE for raw MWCNT-PMMA composites was similar to27 dB, indicating commercial use for far-field EMI shielding. The contribution of absorption to total EMI SE of the systems is larger than that of reflection. Based on magnetic permeability, we suggest raw MWCNTs and their composites can be used for near-field EMI shielding.open28629
Влияние нелинейности сопротивления щеточного контакта на процесс самовозбуждения электромашинного усилителя с поперечным полем на холостом ходу
Retaining Expression on De-identified Faces
© Springer International Publishing AG 2017The extensive use of video surveillance along with advances in face recognition has ignited concerns about the privacy of the people identifiable in the recorded documents. A face de-identification algorithm, named k-Same, has been proposed by prior research and guarantees to thwart face recognition software. However, like many previous attempts in face de-identification, kSame fails to preserve the utility such as gender and expression of the original data. To overcome this, a new algorithm is proposed here to preserve data utility as well as protect privacy. In terms of utility preservation, this new algorithm is capable of preserving not only the category of the facial expression (e.g., happy or sad) but also the intensity of the expression. This new algorithm for face de-identification possesses a great potential especially with real-world images and videos as each facial expression in real life is a continuous motion consisting of images of the same expression with various degrees of intensity.Peer reviewe
The mu problem and sneutrino inflation
We consider sneutrino inflation and post-inflation cosmology in the singlet
extension of the MSSM with approximate Peccei-Quinn(PQ) symmetry, assuming that
supersymmetry breaking is mediated by gauge interaction. The PQ symmetry is
broken by the intermediate-scale VEVs of two flaton fields, which are
determined by the interplay between radiative flaton soft masses and higher
order terms. Then, from the flaton VEVs, we obtain the correct mu term and the
right-handed(RH) neutrino masses for see-saw mechanism. We show that the RH
sneutrino with non-minimal gravity coupling drives inflation, thanks to the
same flaton coupling giving rise to the RH neutrino mass. After inflation,
extra vector-like states, that are responsible for the radiative breaking of
the PQ symmetry, results in thermal inflation with the flaton field, solving
the gravitino problem caused by high reheating temperature. Our model predicts
the spectral index to be n_s\simeq 0.96 due to the additional efoldings from
thermal inflation. We show that a right dark matter abundance comes from the
gravitino of 100 keV mass and a successful baryogenesis is possible via
Affleck-Dine leptogenesis.Comment: 27 pages, no figures, To appear in JHE
Conclusive quantum steering with superconducting transition edge sensors
Quantum steering allows two parties to verify shared entanglement even if one
measurement device is untrusted. A conclusive demonstration of steering through
the violation of a steering inequality is of considerable fundamental interest
and opens up applications in quantum communication. To date all experimental
tests with single photon states have relied on post-selection, allowing
untrusted devices to cheat by hiding unfavourable events in losses. Here we
close this "detection loophole" by combining a highly efficient source of
entangled photon pairs with superconducting transition edge sensors. We achieve
an unprecedented ~62% conditional detection efficiency of entangled photons and
violate a steering inequality with the minimal number of measurement settings
by 48 standard deviations. Our results provide a clear path to practical
applications of steering and to a photonic loophole-free Bell test.Comment: Preprint of 7 pages, 3 figures; the definitive version is published
in Nature Communications, see below. Also, see related experimental work by
A. J. Bennet et al., arXiv:1111.0739 and B. Wittmann et al., arXiv:1111.076
Discrete R-symmetries and Anomaly Universality in Heterotic Orbifolds
We study discrete R-symmetries, which appear in 4D low energy effective field
theory derived from hetetoric orbifold models. We derive the R-symmetries
directly from geometrical symmetries of orbifolds. In particular, we obtain the
corresponding R-charges by requiring that the couplings be invariant under
these symmetries. This allows for a more general treatment than the explicit
computations of correlation functions made previously by the authors, including
models with discrete Wilson lines, and orbifold symmetries beyond
plane-by-plane rotational invariance. Surprisingly, for the cases covered by
earlier explicit computations, the R-charges differ from the previous result.
We study the anomalies associated with these R-symmetries, and comment on the
results.Comment: 21 pages, 2 figures. Minor changes, typos corrected. Matches JHEP
published versio
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