975 research outputs found
Vacuum stability in stau-neutralino coannihilation in MSSM
The stau-neutralino coannihilation provides a feasible way to accommodate the
observed cosmological dark matter (DM) relic density in the minimal
supersymmetric standard model (MSSM). In such a coannihilation mechanism the
stau mass usually has an upper bound since its annihilation rate becomes small
with the increase of DM mass. Inspired by this observation, we examine the
upper limit of stau mass in the parameter space with a large mixing of staus.
We find that the stau pair may dominantly annihilate into dibosons and hence
the upper bound on the stau mass ( GeV) obtained from the
final states can be relaxed. Imposing the DM relic density constraint and
requiring a long lifetime of the present vacuum, we find that the lighter stau
mass can be as heavy as about 1.4 TeV for the stau maximum mixing. However, if
requiring the present vacuum to survive during the thermal history of the
universe, this mass limit will reduce to about 0.9 TeV. We also discuss the
complementarity of vacuum stability and direct detections in probing this stau
coannihilation scenario.Comment: 12 pages, 6 figure
Triple hourglass Weyl phonons
Unconventional Weyl phonons with higher topological charges in crystalline
solids have attracted increasing attention. By symmetry analysis and low-energy
effective Hamiltonian, we propose the symmetry enforced triple hourglass
Weyl phonons (THWPs) with Chern number = 3 protected by
screw rotation symmetry in chiral space groups 173 () and 182
(). We take LiIO with space group 173 as a candidate and confirm
that it possesses THWP with linear and quadratic dispersions along the
direction and in the - plane, respectively. Due to the constraints of
crystal symmetry and topological charge conservation, six equivalent single
Weyl phonons (SWPs) emerge and lie in the = 0 plane. Therefore, the
unique phonon surface arcs connect the projections of two THWPs and six SWPs,
leading to nontrivial sextuple-helicoid surface arcs on the (001) surface
Brillouin zone. Our work proposes a class of topological phonons and realizes
it in realistic materials, providing a perfect platform for experimental
observation of THWPs. We expect our work to provide a new idea for detection of
unconventional quasiparticles.Comment: 11 pages, 7 figure
NPRL2: A New Target In Breast Cancer Treatment
https://openworks.mdanderson.org/sumexp22/1063/thumbnail.jp
Miniaturization of Branch-Line Coupler Using Composite Right/Left-Handed Transmission Lines with Novel Meander-shaped-slots CSSRR
A novel compact-size branch-line coupler using composite right/left-handed transmission lines is proposed in this paper. In order to obtain miniaturization, composite right/left-handed transmission lines with novel complementary split single ring resonators which are realized by loading a pair of meander-shaped-slots in the split of the ring are designed. This novel coupler occupies only 22.8% of the area of the conventional approach at 0.7 GHz. The proposed coupler can be implemented by using the standard printed-circuit-board etching processes without any implementation of lumped elements and via-holes, making it very useful for wireless communication systems. The agreement between measured and stimulated results validates the feasible configuration of the proposed coupler
Building quantum neural networks based on swap test
Artificial neural network, consisting of many neurons in different layers, is
an important method to simulate humain brain. Usually, one neuron has two
operations: one is linear, the other is nonlinear. The linear operation is
inner product and the nonlinear operation is represented by an activation
function. In this work, we introduce a kind of quantum neuron whose inputs and
outputs are quantum states. The inner product and activation operator of the
quantum neurons can be realized by quantum circuits. Based on the quantum
neuron, we propose a model of quantum neural network in which the weights
between neurons are all quantum states. We also construct a quantum circuit to
realize this quantum neural network model. A learning algorithm is proposed
meanwhile. We show the validity of learning algorithm theoretically and
demonstrate the potential of the quantum neural network numerically.Comment: 10 pages, 13 figure
Research on Chloride Penetration Resistance of Hybrid Fiber Reinforced Self-Compacting Concrete
The properties of chloride penetration of hybrid fiber reinforced self-compacting concrete (SCC) were investigated in this study. The results show that, the chloride penetration resistance of concrete can be improved by single incorporation either carbon or cellulose fibers. The concrete chloride diffusion coefficient DRCM of 12-cm length carbon SCC with fiber content of 1.7 kg/m3, 2.72 kg/m3, and 3.4 kg/m3 decreases by 10.3%, 25.5%, and 18.2% compared to reference concrete without any fibers, respectively. Moreover, the concrete chloride diffusion coefficient DRCM of cellulose SCC with fiber content of 1.2 kg/m3, 1.6 kg/m3, and 2.0 kg/m3 decreases by 18.8%, 22.4%, and 26.7% compared to reference concrete, respectively. Based on the results of orthogonal experimental design, the chloride diffusion coefficients DRCM of hybrid fiber reinforced SCC are listed in order of importance, as follows: length of carbon fiber \u3e content of carbon fiber \u3e content of cellulose fiber; furthermore, the hybrid of 2.72-kg/m3 carbon fiber with length of 12mm and 2.0-kg/m3 cellulose fiber exhibits the most significant effect on chloride diffusion coefficients DRCM of SCC
High Serum Estradiol Levels are not Detrimental to In Vitro Fertilization Outcome
SummaryObjectiveTo evaluate the impact of high estradiol (E2) levels and a high number of retrieved oocytes on the outcome of in vitro fertilization (IVF) cycles.Materials and MethodsWe retrospectively reviewed 274 IVF cycles. These patients were divided into five groups according to their peak E2 levels on the human chorionic gonadotropin day: ≤ 2,000 pg/mL (130 cycles); 2,001–3,000 pg/mL (53 cycles); 3,001–4,000 pg/mL (46 cycles); 4,001–5,000 pg/mL (29 cycles); > 5,000 pg/mL (16 cycles). Fertilization, pregnancy, and implantation rates were analyzed between these groups. We also compared the outcome of IVF for high responders (> 15 retrieved oocytes) and normal responders (≤ 15 retrieved oocytes).ResultsThe oocyte fertilization and embryo cleavage rates were not significantly different among these five groups. Although decrease in pregnancy and implantation rates was observed when E2 levels were > 5,000 pg/mL compared with those having lower E2 levels, there were no statistically significant differences between these five groups. In addition, similar IVF outcome was detected for those cycles with > 15 oocytes and ≤ 15 oocytes obtained.ConclusionHigh serum E2 levels and high oocyte yield are not detrimental to IVF outcome. More studies are needed to characterize the threshold E2 levels above which implantation rates are reduced
- …