Deterministic Constructions of Binary Measurement Matrices from Finite Geometry

Deterministic constructions of measurement matrices in compressed sensing (CS) are considered in this paper. The constructions are inspired by the recent discovery of Dimakis, Smarandache and Vontobel which says that parity-check matrices of good low-density parity-check (LDPC) codes can be used as {provably} good measurement matrices for compressed sensing under $\ell_1$-minimization. The performance of the proposed binary measurement matrices is mainly theoretically analyzed with the help of the analyzing methods and results from (finite geometry) LDPC codes. Particularly, several lower bounds of the spark (i.e., the smallest number of columns that are linearly dependent, which totally characterizes the recovery performance of $\ell_0$-minimization) of general binary matrices and finite geometry matrices are obtained and they improve the previously known results in most cases. Simulation results show that the proposed matrices perform comparably to, sometimes even better than, the corresponding Gaussian random matrices. Moreover, the proposed matrices are sparse, binary, and most of them have cyclic or quasi-cyclic structure, which will make the hardware realization convenient and easy.Comment: 12 pages, 11 figure

Spectral and transport properties from lattice QCD

In these lecture notes we will discuss recent progress in extracting spectral and transport properties from lattice QCD. We will focus on results of probes of the thermal QCD medium as well as transport coefficients which are important ingredients for hydrodynamic and transport models that describe the evolution of the produced medium. These include electromagnetic probes, like the rates of emitted photons and dileptons, quarkonium spectral functions as well as transport coefficients like the electrical conductivity or heavy flavor diffusion coefficients of the quark gluon plasma (QGP). All these real time quantities are encoded in the vector meson spectral function. A direct determination of the spectral functions is not possible in Euclidean lattice QCD calculations but they can be analytically continued from imaginary to real time. Therefore it is possible to relate the spectral function to the corresponding Euclidean correlation functions. In the following sections we will discuss the procedure to determine the required correlation functions and the extraction of the spectral functions from lattice QCD correlators. We will illustrate the concepts and methods to obtain spectral functions and related physical observables from continuum extrapolated correlation functions. We will focus here on results obtained from continuum extrapolated lattice correlation functions, which requires large and fine lattices, which so far was only possible in quenched approximation. We will only give a brief introduction to lattice QCD and refer to the textbooks [1,2,3,4] and lecture notes [5] for more detailed introductions to lattice field theory. For the topics addressed in this lecture note we also like to refer to the overview articles on QCD thermodynamics and the QCD phase transition [5,6,7] and quarkonium in extreme conditions [8].Comment: Lectures delivered at the 53rd Karpacz Winter School of Theoretical Physics, February 26th - March 4th, 2017, Karpacz, Poland; submitted to Lecture Notes in Physics (LNP, volume 999), ISBN: 978-3-030-95490-

Study of charm and beauty in QGP from unquenched lattice QCD

We present charmonium and bottomonium correlators and corresponding reconstructed spectral functions from full QCD calculations in the pseudoscalar channel. Correlators are obtained using a mixed-action approach, clover-improved Wilson valence quarks on gauge field configurations generated with $N_f=2+1$ HISQ sea quarks, with physical strange quark masses and light quark masses corresponding to $m_\pi=315$ MeV. The charm and bottom quark masses are tuned to reproduce the experimental mass spectrum of the spin averaged quarkonium vector mesons from the particle data group. For the spectral reconstruction, we use models based on perturbative spectral functions from different frequency regions like resummed thermal contributions around the threshold from pNRQCD and vacuum contributions well above the threshold. We show preliminary results of the reconstructed spectral function obtained for the first time in our study for full QCD

Biomechanics Characteristics of New Type Artificial Hip Joint

The structure, geometrical shape and material are the three main parts of the prostheses. This research focuses on the geometrical shape analysis. The geometrical shape of human natural femoral head is similar to the ellipse, but, the artificial femoral head is rotundity shape. There is difference between ellipse and rotundity femoral head. Two models are developed and analyzed in this paper under same conditions used Finite element analysis method. Based on the calculation results, it is shown that the ellipse shape femoral head have the similar characteristics to the natural joint than rotundity model. The ellipse has the more lowness stress distribution area and more small distortion magnitude than rotundity shape artificial femoral head. It should have the more kind effect replace rotundity femoral head with ellipse shape artificial formal head. Keywords: hip joint; prosthesis design; finite element analysis; biomechanic

Heavy Quark Diffusion from 2+1 Flavor Lattice QCD

We present the first calculations of the heavy flavor diffusion coefficient using lattice QCD with light dynamical quarks. For temperatures $195\,\mathrm{MeV}<T<352\,\mathrm{MeV}$, the heavy quark spatial diffusion coefficient is found to be significantly smaller than previous quenched lattice QCD and recent phenomenological estimates. The result implies very fast hydrodynamization of heavy quarks in the quark-gluon plasma created during ultrarelativistic heavy-ion collision experiments

Continuum extrapolation of the gradient-flowed color-magnetic correlator at 1.5 Tc1.5\,T_c

In a recently published work we employ gradient flow on the lattice to extract the leading contribution of the heavy quark momentum diffusion coefficient in the heavy quark limit from calculations of a well-known two-point function of color-electric field operators. In this article we want to report the progress of calculating the recently derived color-magnetic correlator that encodes a finite mass correction to this transport coefficient. The calculations we present here are based on the same ensemble of quenched gauge configurations at $1.5\, T_c$ that we previously used for the color-electric correlator.Comment: 7 pages, 4 figures, presented at the 38th International Symposium on Lattice Field Theor

[N,N′-Bis(4-chloro­benz­yl)ethane-1,2-diamine]dichloridozinc(II)

In the title complex, [ZnCl2(C16H18Cl2N2)], the asymmetric unit contains one mol­ecule and two half-mol­ecules, which have similar geometric parameters; in the latter two molecules each Zn atom lies on a twofold rotation axis. The environment about each ZnII atom is distorted tetra­hedral with coordination of two terminal Cl atoms and two N atoms of the N,N′-bis­(4-chloro­benz­yl)ethane-1,2-diamine ligand. Four N—H⋯Cl hydrogen bonds link the mol­ecules into a chain of R 2 2(8) rings in the [001] direction