Quantum Bit Commitment with a Composite Evidence

Entanglement-based attacks, which are subtle and powerful, are usually believed to render quantum bit commitment insecure. We point out that the no-go argument leading to this view implicitly assumes the evidence-of-commitment to be a monolithic quantum system. We argue that more general evidence structures, allowing for a composite, hybrid (classical-quantum) evidence, conduce to improved security. In particular, we present and prove the security of the following protocol: Bob sends Alice an anonymous state. She inscribes her commitment $b$ by measuring part of it in the + (for $b = 0$) or $\times$ (for $b=1$) basis. She then communicates to him the (classical) measurement outcome $R_x$ and the part-measured anonymous state interpolated into other, randomly prepared qubits as her evidence-of-commitment.Comment: 6 pages, minor changes, journal reference adde

PPM demodulation for Reed-Solomon decoding for the optical space channel

The use of Reed-Solomon (RS) block codes over the pulse position modulated (PPM) frames to obtain the largest degree of error correction is considered. Since RS codes can correct both symbol errors and symbol erasures, a question arises as to the best way to demodulate the PPM laser fields in order to generate the input symbols for the RS decoder. The method selected for demodulating (converting the received laser field to digital symbols) defines the erasure and transmitted symbols of the laser link, and therefore determines the work error probabilities of the system. Several demodulating schemes are considered, and the effect of each on RS decoding performance computed. This computation was carried out for various optical receiver models. It is shown that simple threshold decisioning of pulse slots produces performance that degrades as the background noise increases. This is caused by the generation of too many erasures for the RS decoder to handle. A decision scheme, delta-max demodulation which offers improvement over threshold decisioning by redefining the generation of an erasure is proposed

Changes in Polarization Position Angle across the Eclipse in the Double Pulsar System

We investigate the changes in polarization position angle in radiation from pulsar A around the eclipse in the Double Pulsar system PSR J0737-3039A/B at the 20 cm and 50 cm wavelengths using the Parkes 64-m telescope. The changes are ~2\sigma\ during and shortly after the eclipse at 20 cm but less significant at 50 cm. We show that the changes in position angle during the eclipse can be modelled by differential synchrotron absorption in the eclipse regions. Position angle changes after the eclipse are interpreted as Faraday rotation in the magnetotail of pulsar B. Implied charge densities are consistent with the Goldreich-Julian density, suggesting that the particle energies in the magnetotail are mildly relativistic.Comment: Accepted for publication in The Astrophysical Journal Letter

Self-Similar Blowup Solutions to the 2-Component Camassa-Holm Equations

In this article, we study the self-similar solutions of the 2-component Camassa-Holm equations% \begin{equation} \left\{ \begin{array} [c]{c}% \rho_{t}+u\rho_{x}+\rho u_{x}=0 m_{t}+2u_{x}m+um_{x}+\sigma\rho\rho_{x}=0 \end{array} \right. \end{equation} with \begin{equation} m=u-\alpha^{2}u_{xx}. \end{equation} By the separation method, we can obtain a class of blowup or global solutions for $\sigma=1$ or $-1$. In particular, for the integrable system with $\sigma=1$, we have the global solutions:% \begin{equation} \left\{ \begin{array} [c]{c}% \rho(t,x)=\left\{ \begin{array} [c]{c}% \frac{f\left( \eta\right) }{a(3t)^{1/3}},\text{ for }\eta^{2}<\frac {\alpha^{2}}{\xi} 0,\text{ for }\eta^{2}\geq\frac{\alpha^{2}}{\xi}% \end{array} \right. ,u(t,x)=\frac{\overset{\cdot}{a}(3t)}{a(3t)}x \overset{\cdot\cdot}{a}(s)-\frac{\xi}{3a(s)^{1/3}}=0,\text{ }a(0)=a_{0}% >0,\text{ }\overset{\cdot}{a}(0)=a_{1} f(\eta)=\xi\sqrt{-\frac{1}{\xi}\eta^{2}+\left( \frac{\alpha}{\xi}\right) ^{2}}% \end{array} \right. \end{equation} where $\eta=\frac{x}{a(s)^{1/3}}$ with $s=3t;$ $\xi>0$ and $\alpha\geq0$ are arbitrary constants.\newline Our analytical solutions could provide concrete examples for testing the validation and stabilities of numerical methods for the systems.Comment: 5 more figures can be found in the corresponding journal paper (J. Math. Phys. 51, 093524 (2010) ). Key Words: 2-Component Camassa-Holm Equations, Shallow Water System, Analytical Solutions, Blowup, Global, Self-Similar, Separation Method, Construction of Solutions, Moving Boundar

Maine Distributed Solar Valuation Study

During its 2014 session, the Maine Legislature enacted an Act to Support Solar Energy Development in Maine. P.L Chapter 562 (April 24, 2014) (codified at 35‐A M.R.S. §§ 3471‐3473) (“Act”). Section 1 of the Act contains the Legislative finding that it is in the public interest is to develop renewable energy resources, including solar energy, in a manner that protects and improves the health and well‐being of the citizens and natural environment of the State while also providing economic benefits to communities, ratepayers and the overall economy of the State. Section 2 of the Act requires the Public Utilities Commission (Commission) to determine the value of distributed solar energy generation in the State, evaluate implementation options, and to deliver a report to the Legislature. To support this work, the Commission engaged a project team comprising Clean Power Research (Napa, California), Sustainable Energy Advantage (Framingham, Massachusetts), Pace Energy and Climate Center at the Pace Law School (White Plains, New York), and Dr. Richard Perez (Albany, New York). Under the project, the team developed the methodology under a Commission‐run stakeholder review process, conducted a valuation on distributed solar for three utility territories, and developed a summary of implementation options for increasing deployment of distributed solar generation in the State. The report includes three volumes which accompany this Executive Summary: Volume I Methodology; Volume II Valuation Results; Volume III Implementation Options

Cultural Recovery and Determination of Antimicrobial Susceptibility in Helicobacter pylori by Using Commercial Transport and Isolation Media

Abstract : Background: : Antimicrobial resistance of Helicobacter pylori is the main reason for eradication failure. We have studied the feasibility of a commercial transport medium for cultural recovery and subsequent drug susceptibility testing. Patients and Methods: : From March to December 2000, 79 consecutive gastric biopsies, positive in a rapid urease test, were transferred into a commercial transport medium and sent within 24 hours from the district hospital to the microbiological laboratory for culture and susceptibility testing. A commercial agar plate and an in-house Wilkins-Chalgren agar plate were used for culture. Susceptibility data were compared with data collected from 1992 to 2003 in the University Hospital of Zurich. Results: : Cultural recovery and susceptibility testing of H. pylori was successful in 55 of 79 patients. In 17 cases cultural recovery failed because of technical problems (n = 14), long transport time (n = 1) and unknown reason (n = 2). Failure of susceptibility testing (n = 7) was mainly due to fungal overgrowth. Resistance to metronidazole and clarithromycin was found in 15 (27%) and in 12 patients (22%), respectively; resistance to amoxicillin was not observed. Five patients (9%) showed resistance both to metronidazole and to clarithromycin. Eradication therapy failed in all patients with macrolide resistance. Resistance rates were higher in females than in males; 30% vs 12% for clarithromycin and 33% vs 20% for metronidazole. Resistance to metronidazole was significantly lower in Swiss patients (15%) than in non-Swiss patients (39%). Conclusion: : Antimicrobial resistance data can reliably be obtained by sending the biopsy specimen in a commercial transport medium to a microbiological laboratory. This is especially important after eradication failure. Resistance to metronidazole and clarithromycin is highly prevalent and more common in women and non-Swiss patient

Applications of the group SU(1,1) for quantum computation and tomography

This paper collects miscellaneous results about the group SU(1,1) that are helpful in applications in quantum optics. Moreover, we derive two new results, the first is about the approximability of SU(1,1) elements by a finite set of elementary gates, and the second is about the regularization of group identities for tomographic purposes.Comment: 11 pages, no figure

Behaviour of parallel girders stabilised with u-frames

Lateral torsional buckling is a key factor in the design of steel girders. Stability can be enhanced by cross‐bracing, reducing the effective length and thus increasing the ultimate capacity. U‐frames are an option often used to brace the girders, when designing through type of bridges and where overhead bracing is not practical. This paper investigates the effect of the U‐frame spacing on the stability of the parallel girders. Eigenvalue buckling analysis was undertaken with four different spacings of the U‐frames. Results were extracted from finite element analysis, interpreted and conclusions drawn

Minimum-error discrimination between subsets of linearly dependent quantum states

A measurement strategy is developed for a new kind of hypothesis testing. It assigns, with minimum probability of error, the state of a quantum system to one or the other of two complementary subsets of a set of N given non-orthogonal quantum states occurring with given a priori probabilities. A general analytical solution is obtained for N states that are restricted to a two-dimensional subspace of the Hilbert space of the system. The result for the special case of three arbitrary but linearly dependent states is applied to a variety of sets of three states that are symmetric and equally probable. It is found that, in this case, the minimum error probability for distinguishing one of the states from the other two is only about half as large as the minimum error probability for distinguishing all three states individually.Comment: Representation improved and generalized, references added. Accepted as a Rapid Communication in Phys. Rev.