Practical figures of merit and thresholds for entanglement distribution in quantum networks

Before global-scale quantum networks become operational, it is important to consider how to evaluate their performance so that they can be built to achieve the desired performance. We propose two practical figures of merit for the performance of a quantum network: the average connection time and the average largest entanglement cluster size. These quantities are based on the generation of elementary links in a quantum network, which is a crucial initial requirement that must be met before any long-range entanglement distribution can be achieved and is inherently probabilistic with current implementations. We obtain bounds on these figures of merit for a particular class of quantum repeater protocols consisting of repeat-until-success elementary link generation followed by joining measurements at intermediate nodes that extend the entanglement range. Our results lead to requirements on quantum memory coherence times, requirements on repeater chain lengths in order to surpass the repeaterless rate limit, and requirements on other aspects of quantum network implementations. These requirements are based solely on the inherently probabilistic nature of elementary link generation in quantum networks, and they apply to networks with arbitrary topology.Comment: 17 pages, 7 figures. v2: extensively revised and rewritten. Title and abstract modified; added a section on overcoming the repeaterless rate limit; modified statement of Theorem 1. v3: minor changes to match the published versio

Mathematical Modelling of Blood Flow through Catheterized Artery under the Influence of Body Acceleration with Slip Velocity

The flow of blood through stenosed catheterized artery with the effect of external body acceleration has been considered. The pulsatile flow behaviour of blood in an artery subjected to the pulsatile pressure gradient and slip velocity has been studied considering blood as a Newtonian fluid. The non-linear differential equations governing the fluid flow are solved using the perturbation method. The analytic expressions are derived for the velocity profile, flow rate, wall shear stress and effective viscosity. The computer codes are developed for the analysis of physiological parameters. The effects of various parameters on blood flow are discussed through graphs. It is observed that insertion of catheter increases the wall shear stress enormously depending upon the size of the catheter. Body acceleration enhances the axial velocity and flow rate. However it is found that with the application of slip velocity, the wall shear stress is significantly decreases

Blood Flow through a Composite Stenosis in an Artery with Permeable Wall

The present work concerns the fluid mechanical study on the effects of the permeability of the wall through an artery with a composite stenosis. The expressions for the blood flow characteristics, the flow resistance, the wall shear stress, shearing stress at the stenosis throat have been derived. Results for the effect of permeability on these flow characteristics are shown graphically and discussed briefly

Stressing Out Modern Quantum Hardware: Performance Evaluation and Execution Insights

Quantum hardware is progressing at a rapid pace and, alongside this progression, it is vital to challenge the capabilities of these machines using functionally complex algorithms. Doing so provides direct insights into the current capabilities of modern quantum hardware and where its breaking points lie. Stress testing is a technique used to evaluate a system by giving it a computational load beyond its specified thresholds and identifying the capacity under which it fails. We conduct a qualitative and quantitative evaluation of the Quantinuum H1 ion trap device using a stress test based protocol. Specifically, we utilize the quantum machine learning algorithm, the Quantum Neuron Born Machine, as the computationally intensive load for the device. Then, we linearly scale the number of repeat-until-success subroutines within the algorithm to determine the load under which the hardware fails and where the failure occurred within the quantum stack. Using this proposed method, we assess the hardware capacity to manage a computationally intensive QML algorithm and evaluate the hardware performance as the functional complexity of the algorithm is scaled. Alongside the quantitative performance results, we provide a qualitative discussion and resource estimation based on the insights obtained from conducting the stress test with the QNBM.Comment: 13 pages, 7 Figures, 3 Table

Local Damage of Plain and Reinforced Concrete Targets under Impact Load

In the present study, simplified models for calculating the penetration depth, scabbing, and perforation thicknesses for concrete targets have been proposed. These models consider the dynamic strain rate effect in the estimation of penetration parameters. The results of proposed model have been compared with the experimental data

Electrochemically modified viscose-rayon-based activated carbon cloth for competitive and noncompetitive sorption of trace cobalt and lead ions from aqueous solution

A viscose-rayon-based activated carbon cloth (ACC) was electrochemically oxidised. As-received and electrochemically modified ACCs were characterised by sodium capacity, pH titration, elemental analysis and Fourier transform infra red (FTIR) spectroscopy analysis. Cobalt and lead noncompetitive sorption capacities for electrochemically oxidised ACC (EO) are 4.3 and 3.9 times, respectively higher than those for unoxidised ACC (UO). Cobalt and lead competitive sorption capacities for EO are 4.1 and 5.1 times, respectively higher than those for UO. Sorption of cobalt and lead onto EO was by ion exchange, while that onto UO was by surface complex formation. Affinity order of metals sorbed by EO and UO is Pb2+ > Co2+. Metal uptake onto EO increased with an increase in solution pH

A MATHEMATICAL MODEL TO STUDY THE SIMILARITIES OF BLOOD FLUID MODELS THROUGH INCLINED MULTI-STENOSED ARTERY

A mathematical model is presented to comparative steady of the flow behavior of Casson’s and Bingham Plastic fluid model through an inclined tube of non-uniform cross-section with multiple stenoses. The equation describing the flow has been solved and the expressions parameters on flow variables have been studied. The present study may be helpful for better understanding the flow characteristics of blood having multiple stenoses. The graphical representations have been made to validate the analytical findings with a view of its applicability to stenotic diseases. It is found that the flow of resistance increases with the height of the stenosis but decreases with the angle of inclination. The flow characteristics namely, velocity, pressure gradient, flow rate, resistance to flow have been derived. It is shown that the resistance to flow increases with the height of the secondary stenosis as well as with the yield stress. The results are compared with the available data presented by previous researchers

Micellization of Cobalt Hexamrnine Soaps in Methanol-Benzene Mixture

124-12

Interaction of Cationic Surfactants with Polytungstate

346-34

Interaction of Cationic Surfactants with Polytungstate

346-34