Purification of Single-photon Entanglement

Single-photon entanglement is a simple form of entanglement that exists between two spatial modes sharing a single photon. Despite its elementary form, it provides a resource as useful as polarization-entangled photons and it can be used for quantum teleportation and entanglement swapping operations. Here, we report the first experiment where single-photon entanglement is purified with a simple linear-optics based protocol. Besides its conceptual interest, this result might find applications in long distance quantum communication based on quantum repeaters.Comment: Main article: 5 pages, 4 figure

Simulation of Claylike Colloids

We investigate properties of dense suspensions and sediments of small spherical silt particles by means of a combined Molecular Dynamics (MD) and Stochastic Rotation Dynamics (SRD) simulation. We include van der Waals and effective electrostatic interactions between the colloidal particles, as well as Brownian motion and hydrodynamic interactions which are calculated in the SRD-part. We present the simulation technique and first results. We have measured velocity distributions, diffusion coefficients, sedimentation velocity, spatial correlation functions and we have explored the phase diagram depending on the parameters of the potentials and on the volume fraction.Comment: 20 pages, 14 figure

What Is the Required Certainty of Evidence for the Implementation of Novel Techniques for the Treatment of Benign Prostatic Obstruction?

Peer reviewedPostprin

Stress in frictionless granular material: Adaptive Network Simulations

We present a minimalistic approach to simulations of force transmission through granular systems. We start from a configuration containing cohesive (tensile) contact forces and use an adaptive procedure to find the stable configuration with no tensile contact forces. The procedure works by sequentially removing and adding individual contacts between adjacent beads, while the bead positions are not modified. In a series of two-dimensional realizations, the resulting force networks are shown to satisfy a linear constraint among the three components of average stress, as anticipated by recent theories. The coefficients in the linear constraint remain nearly constant for a range of shear loadings up to about .6 of the normal loading. The spatial distribution of contact forces shows strong concentration along ``force chains". The probability of contact forces of magnitude f shows an exponential falloff with f. The response to a local perturbing force is concentrated along two characteristic rays directed downward and laterally.Comment: 8 pages, 8 figure

The DiskMass Survey. I. Overview

We present a survey of the mass surface-density of spiral disks, motivated by outstanding uncertainties in rotation-curve decompositions. Our method exploits integral-field spectroscopy to measure stellar and gas kinematics in nearly face-on galaxies sampled at 515, 660, and 860 nm, using the custom-built SparsePak and PPak instruments. A two-tiered sample, selected from the UGC, includes 146 nearly face-on galaxies, with B<14.7 and disk scale-lengths between 10 and 20 arcsec, for which we have obtained H-alpha velocity-fields; and a representative 46-galaxy subset for which we have obtained stellar velocities and velocity dispersions. Based on re-calibration of extant photometric and spectroscopic data, we show these galaxies span factors of 100 in L(K) (0.03 < L/L(K)* < 3), 8 in L(B)/L(K), 10 in R-band disk central surface-brightness, with distances between 15 and 200 Mpc. The survey is augmented by 4-70 micron Spitzer IRAC and MIPS photometry, ground-based UBVRIJHK photometry, and HI aperture-synthesis imaging. We outline the spectroscopic analysis protocol for deriving precise and accurate line-of-sight stellar velocity dispersions. Our key measurement is the dynamical disk-mass surface-density. Star-formation rates and kinematic and photometric regularity of galaxy disks are also central products of the study. The survey is designed to yield random and systematic errors small enough (i) to confirm or disprove the maximum-disk hypothesis for intermediate-type disk galaxies, (ii) to provide an absolute calibration of the stellar mass-to-light ratio well below uncertainties in present-day stellar-population synthesis models, and (iii) to make significant progress in defining the shape of dark halos in the inner regions of disk galaxies.Comment: To appear in ApJ; 72 pages, 3 tables, 18 figures. High-resolution version available at http://www.astro.wisc.edu/~mab/publications/DMS_I_preprint.pd

The DiskMass Survey. II. Error Budget

We present a performance analysis of the DiskMass Survey. The survey uses collisionless tracers in the form of disk stars to measure the surface-density of spiral disks, to provide an absolute calibration of the stellar mass-to-light ratio, and to yield robust estimates of the dark-matter halo density profile in the inner regions of galaxies. We find a disk inclination range of 25-35 degrees is optimal for our measurements, consistent with our survey design to select nearly face-on galaxies. Uncertainties in disk scale-heights are significant, but can be estimated from radial scale-lengths to 25% now, and more precisely in the future. We detail the spectroscopic analysis used to derive line-of-sight velocity dispersions, precise at low surface-brightness, and accurate in the presence of composite stellar populations. Our methods take full advantage of large-grasp integral-field spectroscopy and an extensive library of observed stars. We show that the baryon-to-total mass fraction (F_b) is not a well-defined observational quantity because it is coupled to the halo mass model. This remains true even when the disk mass is known and spatially-extended rotation curves are available. In contrast, the fraction of the rotation speed supplied by the disk at 2.2 scale lengths (disk maximality) is a robust observational indicator of the baryonic disk contribution to the potential. We construct the error-budget for the key quantities: dynamical disk mass surface-density, disk stellar mass-to-light ratio, and disk maximality (V_disk / V_circular). Random and systematic errors in these quantities for individual galaxies will be ~25%, while survey precision for sample quartiles are reduced to 10%, largely devoid of systematic errors outside of distance uncertainties.Comment: To appear in ApJ; 88 pages, 4 tables, 18 figures. High-resolution version available at http://www.astro.wisc.edu/~mab/publications/DMS_II_preprint.pd

Management of Urinary Retention in Patients with Benign Prostatic Obstruction : A Systematic Review and Meta-analysis

Context: Practice patterns for the management of urinary retention (UR) secondary to benign prostatic obstruction (BPO; UR/BPO) vary widely and remain unstandardized. Objective: To review the evidence for managing patients with UR/BPO with pharmacological and nonpharmacological treatments included in the European Association of Urology guidelines on non-neurogenic male lower urinary tract symptoms. Evidence acquisition: Search was conducted up to April 22, 2018, using CENTRAL, MEDLINE, Embase, ClinicalTrials.gov, and World Health Organization International Clinical Trials Registry Platform. This systematic review included randomized controlled trials (RCTs) and prospective comparative studies. Methods as detailed in the Cochrane handbook were followed. Certainty of evidence (CoE) was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. Evidence synthesis: Literature search identified 2074 citations. Twenty-one studies were included (qualitative synthesis). The evidence for managing patients with UR/BPO with pharmacological or nonpharmacological treatments is limited. CoE for most outcomes was low/very low. Only alpha 1-blockers (alfuzosin and tamsulosin) have been evaluated in more than one RCT. Pooled results indicated that a1-blockers provided significantly higher rates of successful trial without catheter compared with placebo [alfuzosin: 322/540 (60%) vs 156/400 (39%) (odds ratio {OR} 2.28, 95% confidence interval {CI} 1.55 to 3.36; participants = 940; studies = 7; I-2 = 41%; low CoE); tamsulosin: 75/158 (47%) vs 40/139 (29%) (OR 2.40, 95% CI 1.29 to 4.45; participants = 297; studies = 3; I-2 = 30%; low CoE)] with rare adverse events. Similar rates were achieved with tamsulosin or alfuzosin [51/87 (59%) vs 45/84 (54%) (OR 1.28, 95% CI 0.68 to 2.41;participants = 171; studies = 2; I-2 = 0%; very low CoE)]. Nonpharmacological treatments have been evaluated in RCTs/prospective comparative studies only sporadically. Conclusions: There is some evidence that usage of alpha 1-blockers (alfuzosin and tamsulosin) may improve resolution of UR/BPO. As most nonpharmacological treatments have not been evaluated in patients with UR/BPO, the evidence is inconclusive about their benefits and harms. Patient summary: There is some evidence that alfuzosin and tamsulosin may increase the rates of successful trial without catheter, but little or no evidence on various nonpharmacological treatment options for managing patients with urinary retention secondary to benign prostatic obstruction. (c) 2019 European Association of Urology. Published by Elsevier B.V. All rights reserved.Peer reviewe

A distinct topology of BTN3A IgV and B30.2 domains controlled by juxtamembrane regions favors optimal human γδ T cell phosphoantigen sensing

Abstract Butyrophilin (BTN)–3A and BTN2A1 molecules control the activation of human Vγ9Vδ2 T cells during T cell receptor (TCR)-mediated sensing of phosphoantigens (PAg) derived from microbes and tumors. However, the molecular rules governing PAg sensing remain largely unknown. Here, we establish three mechanistic principles of PAg-mediated γδ T cell activation. First, in humans, following PAg binding to the intracellular BTN3A1-B30.2 domain, Vγ9Vδ2 TCR triggering involves the extracellular V-domain of BTN3A2/BTN3A3. Moreover, the localization of both protein domains on different chains of the BTN3A homo-or heteromers is essential for efficient PAg-mediated activation. Second, the formation of BTN3A homo-or heteromers, which differ in intracellular trafficking and conformation, is controlled by molecular interactions between the juxtamembrane regions of the BTN3A chains. Finally, the ability of PAg not simply to bind BTN3A-B30.2, but to promote its subsequent interaction with the BTN2A1-B30.2 domain, is essential for T-cell activation. Defining these determinants of cooperation and the division of labor in BTN proteins improves our understanding of PAg sensing and elucidates a mode of action that may apply to other BTN family members

Chiral unitary theory: application to nuclear problems

In this talk we briefly describe some basic elements of chiral perturbation theory, $\chi PT$, and how the implementation of unitarity and other novel elements lead to a better expansion of the $T$ matrix for meson meson and meson baryon interactions. Applications are then done to the $\pi \pi$ interaction in nuclear matter in the scalar and vector channels, antikaons in nuclei and $K^-$ atoms, and how the $\phi$ meson properties are changed in a nuclear medium.Comment: 15 pages, 9 figures, Invited talk in the International Symposium on Nuclear Physics, Bombay, december 200