Strong Asymptotics Of Pade Polynomials

New results about the strong asymptotic behaviour of diagonal Pade polynomials of high degree are obtained for certain functions with branch points. The method, a modification of a previous approach, uses a singular integral equation for the remainder function restricted to a preferred set. New techniques are developed to analyze three cases (1) a branch point not of square-root type; (2) a case where the preferred set contains three intersecting arcs; (3) a case where not all zeros of the polynomials approach the preferred set.;The first two cases have not previously been treated. The method involves approximating the kernel of the integral equation so that the resulting equation may be solved analytically. The third case has been treated before by a different method, but it is important to show that the new method can handle this case

Prevalence, Risk Factors, and Management of Prehypertension

Prehypertension remains an important public health challenge all over the world and appropriate treatments should be adopted to prehypertensive group in different degree effectively. This review aimed to assess the prevalence of Prehypertension and provide effective evidence of the benefits of treating prehypertensive patients. The reasonable evaluation and appropriate intervention of prehypertensive remain need further study

Background-Free Microwave Signal Generation Based on Unbalanced Temporal Pulse Shaping

We propose a new method to generate background-free high-frequency pulsed microwave signal based on an unbalanced temporal optical pulse shaping (TPS) system and balanced photodetection. The proposed system consists of a polarization modulator and an unbalanced TPS system realized by two conjugate dispersion elements. The carrier frequency of the pulsed microwave signal could be tuned by changing the residual dispersion of the TPS. The proposed method is theoretically analyzed and experimentally demonstrated. The experimental results show that the carrier frequency of the generated microwave pulse could be tuned over a broad frequency range. Moreover, the generated microwave pulse signal is background-free by suppressing the baseband frequency components using balanced photodetection

Surpassing the classical limit of microwave photonic frequency fading effect by quantum microwave photonics

With energy-time entangled biphoton sources as the optical carrier and time-correlated single-photon detection for high-speed radio frequency (RF) signal recovery, the method of quantum microwave photonics (QMWP) has presented the unprecedented potential of nonlocal RF signal encoding and efficient RF signal distilling from the dispersion interference associated with ultrashort pulse carriers. In this letter, its capability in microwave signal processing and prospective superiority is further demonstrated. Both the QMWP RF phase shifting and transversal filtering functionality, which are the fundamental building blocks of microwave signal processing, are realized. Besides the perfect immunity to the dispersion-induced frequency fading effect associated with the broadband carrier in classical microwave photonics, a native two-dimensional parallel microwave signal processor is provided. These demonstrations fully prove the superiority of QMWP over classical MWP and open the door to new application fields of MWP involving encrypted processing

Hierarchical Liouville-space approach for accurate and universal characterization of quantum impurity systems

A hierarchical equations of motion (HEOM) based numerical approach is developed for accurate and efficient evaluation of dynamical observables of strongly correlated quantum impurity systems. This approach is capable of describing quantitatively Kondo resonance and Fermi liquid characteristics, achieving the accuracy of latest high-level numerical renormalization group approach, as demonstrated on single-impurity Anderson model systems. Its application to a two-impurity Anderson model results in differential conductance versus external bias, which correctly reproduces the continuous transition from Kondo states of individual impurity to singlet spin-states formed between two impurities. The outstanding performance on characterizing both equilibrium and nonequilibrium properties of quantum impurity systems makes the HEOM approach potentially useful for addressing strongly correlated lattice systems in the frame work of dynamical mean field theory.Comment: 5 pages, 4 figures, to appear in PR