Probing Lorentz Invariance Violation with Neutrino Factories

In this article we show the modification in the number of neutrino events ($\nu_\mu+\bar\nu_\mu$) caused by Lorentz Invariant Violation (LIV), $\sigma=5\times 10^{-24}$ and $10^{-23}$, in neutrino oscillation for a neutrino factory at a distance of 7500 km. The momentum of the muons can vary from 10-50 GeV and we consider $2\times 10^{20}$ decays per year. The modifications in the number of events caused by this $\sigma$ LIV parameter could be a strong signal of new physics in a future neutrino factory.Comment: 8 pages, 6 figures. Several improvements in the text. New references added. Improvements in the discussions and conclusion

Electron-phonon coupling in metallic carbon nanotubes: Dispersionless electron propagation despite dissipation

A recent study [Rosati, Dolcini, and Rossi, Appl. Phys. Lett. 106, 243101 (2015)] has predicted that, while in semiconducting single-walled carbon nanotubes (SWNTs) an electronic wave packet experiences the typical spatial diffusion of conventional materials, in metallic SWNTs its shape remains essentially unaltered up to micron distances at room temperature, even in the presence of the electron-phonon coupling. Here, by utilizing a Lindblad-based density-matrix approach enabling us to account for both dissipation and decoherence effects, we test such prediction by analyzing various aspects that were so far unexplored. In particular, accounting for initial nonequilibrium excitations, characterized by an excess energy $E_0$, and including both intra- and interband phonon scattering, we show that for realistically high values of $E_0$ the electronic diffusion is extremely small and nearly independent of its energetic distribution, in spite of a significant energy-dissipation and decoherence dynamics. Furthermore, we demonstrate that the effect is robust with respect to the variation of the chemical potential. Our results thus suggest that metallic SWNTs are a promising platform to realise quantum channels for the non-dispersive transmission of electronic wave packets.Comment: 14 pages, 7 figure

Field-induced Coulomb coupling in semiconductor macroatoms: application to "single-electron" quantum devices

A novel approach for the control of exciton-exciton Coulomb coupling in semiconductor macroatoms/molecules is proposed. We show that by applying properly tailored external fields, we can induce ---or significantly reinforce--- excitonic dipoles, which in turn allows to control and magnify intra- as well as inter-dot few-exciton effects. Such dipole-dipole interaction mechanism will be accounted for within a simple analytical model, which is found to be in good agreement with fully three-dimensional calculations. The proposed approach may play an important role for the design and realization of fully-optical quantum gates as well as ultrafast optical switches

A RECONSTRUCTION OF THE GREEK-ROMAN REPEATING CATAPULT

An “automatic” repeating weapon used by the Roman army is presented. Firstly a short description is shown of the working principle of the torsion motor that powered the Greek-Roman catapults. This is followed by the description of the reconstructions of these ancient weapons made by those scientists who studied repeating catapults. The authors then propose their own reconstruction. The latter differs from the previous ones because it proposes a different working cycle that is almost automatic and much safer for the operators. The authors based their reconstruction of the weapon starting from the work of previous scientists and on their own translation of the original text (in ancient Greek) by Philon of Byzantium

The failed amnesty of the ‘years of lead’ in Italy: Continuity and transformations between (de)politicization and punitiveness

The ‘years of lead’ commonly refer in Italy to the decade of the 1970s, characterized by widespread conflictuality, the use of violence for political aims and harsh state repression of political activism. Political violence has been primarily handled with both normal and exceptional means of criminal justice, yet debates on amnesty and reconciliation have been recurrent over the years. This article traces the history of the debates on amnesty and pardon for politically motivated offences to show how they have been shaped by changing national and international contexts. On the one hand, the ‘failed amnesty’ reflects the long-lasting repressive approach adopted by the Italian state to address the question of the political violence in the 1970s and the reluctance to acknowledge its collective and political character. On the other hand, this article argues that, beyond the apparent continuity of a punitive approach, the gradual disappearance of amnesty from political debates in the 1990s–2000s is symptomatic of a more paradigmatic shift resulting from the combination of different factors and trends, such as the transformation of the Italian political landscape in the early 1990s, the emergence and affirmation of a new punitive discourse, as well as the increasing delegitimation of amnesties in transitional settings. Thus, through a specific case-study, this article draws links between criminal justice and penal trends, political transformations and developments in transitional justice, and consequently intends to contribute to the discussion of the concept of punitiveness and the effects of the expanding international criminal law on the treatment of politically motivated offences

Investigating local buckling in highly slender elliptical hollow sections through analysis of 3D-printed analogues

Tubular structural members with slender cross-sections are susceptible to failure through local buckling of their tube walls. Previous numerical studies of steel elliptical hollow sections in compression predicted the local buckling modes and the ultimate loads of particularly slender specimens, with the results used to calibrate design methods for slender elliptical sections. Although these numerical parametric studies were conducted across a wide slenderness range, it was only possible to validate the models against experimental results in the low slenderness range since commercially-available steel EHS are intended to satisfy non-slender geometric limits prescribed by structural design codes. Such limitations to the experimental scope are circumvented in the present study through testing of highly-slender specimens produced using additive manufacturing techniques. A total of eight specimens of various cross-sectional aspect ratios and tube wall thicknesses were fabricated at London South Bank University using additive manufacturing techniques, which were then tested in compression; the observed load-deflection behaviour, ultimate loads, longitudinal strains and failure modes are discussed. Through appropriate rescaling of relevant parameters, design predictions for the ultimate load of the 3D-printed analogues are obtained using a design method intended for use with steel elliptical hollow sections. It is shown that the design predictions are safe-sided when compared to the present experimental results, with the accuracy generally increasing with aspect ratio and slenderness

Characterisation of the fused silica surface quality with a β-source

A method to characterise the quality of a fused silica surface using a β-source is presented. Two fused silica bars (5×10×400mm3) were fabricated for the Cherenkov detector for proton Flux Measurement installed at vacuum chamber of the Super Proton Synchrotron at CERN. The resolution of such device is defined by the collection efficiency of the Cherenkov light, which is produced by relativistic charged particles in the fused silica. Thus, the surface quality of the radiator should be as good as possible to avoid light losses. The method is based on the scanning of the radiator surface with a90Sr radioactive source and measurements of the Cherenkov light rate, detected by a PMT attached to the quartz bars. The data have been compared with a Monte-Carlo simulation, providing an estimation of the radiator's probability of the total internal reflection and inefficient area at the edges of the bars

Matching under Preferences

Matching theory studies how agents and/or objects from different sets can be matched with each other while taking agents\u2019 preferences into account. The theory originated in 1962 with a celebrated paper by David Gale and Lloyd Shapley (1962), in which they proposed the Stable Marriage Algorithm as a solution to the problem of two-sided matching. Since then, this theory has been successfully applied to many real-world problems such as matching students to universities, doctors to hospitals, kidney transplant patients to donors, and tenants to houses. This chapter will focus on algorithmic as well as strategic issues of matching theory. Many large-scale centralized allocation processes can be modelled by matching problems where agents have preferences over one another. For example, in China, over 10 million students apply for admission to higher education annually through a centralized process. The inputs to the matching scheme include the students\u2019 preferences over universities, and vice versa, and the capacities of each university. The task is to construct a matching that is in some sense optimal with respect to these inputs. Economists have long understood the problems with decentralized matching markets, which can suffer from such undesirable properties as unravelling, congestion and exploding offers (see Roth and Xing, 1994, for details). For centralized markets, constructing allocations by hand for large problem instances is clearly infeasible. Thus centralized mechanisms are required for automating the allocation process. Given the large number of agents typically involved, the computational efficiency of a mechanism's underlying algorithm is of paramount importance. Thus we seek polynomial-time algorithms for the underlying matching problems. Equally important are considerations of strategy: an agent (or a coalition of agents) may manipulate their input to the matching scheme (e.g., by misrepresenting their true preferences or underreporting their capacity) in order to try to improve their outcome. A desirable property of a mechanism is strategyproofness, which ensures that it is in the best interests of an agent to behave truthfully

Uncertainty in Soft Temporal Constraint Problems:A General Framework and Controllability Algorithms forThe Fuzzy Case

In real-life temporal scenarios, uncertainty and preferences are often essential and coexisting aspects. We present a formalism where quantitative temporal constraints with both preferences and uncertainty can be defined. We show how three classical notions of controllability (that is, strong, weak, and dynamic), which have been developed for uncertain temporal problems, can be generalized to handle preferences as well. After defining this general framework, we focus on problems where preferences follow the fuzzy approach, and with properties that assure tractability. For such problems, we propose algorithms to check the presence of the controllability properties. In particular, we show that in such a setting dealing simultaneously with preferences and uncertainty does not increase the complexity of controllability testing. We also develop a dynamic execution algorithm, of polynomial complexity, that produces temporal plans under uncertainty that are optimal with respect to fuzzy preferences