49 research outputs found
Comparing different approaches for generating random numbers device-independently using a photon pair source
What is the most efficient way to generate random numbers
device-independently using a photon pair source based on spontaneous parametric
down conversion (SPDC)? We consider this question by comparing two
implementations of a detection-loophole-free Bell test. In particular, we study
in detail a scenario where a heralded single photon source (HSPS) is used to
herald path-entangled states, i.e. entanglement between two spatial modes
sharing a single photon and where non-locality is revealed using photon
counting preceded by small displacement operations. We start by giving a
theoretical description of such a measurement. We then show how to optimize the
Bell-CHSH violation through a non-perturbative calculation, taking the main
experimental imperfections into account. We finally bound the amount of
randomness that can be extracted and compare it to the one obtained with the
conventional scenario using photon pairs entangled e.g. in polarization and
analyzed through photon counting. While the former requires higher overall
detection efficiencies, it is far more efficient in terms of both the entropy
per experimental run and the rate of random bit generation.Comment: 12 pages, 5 figure
Positron sources using channeling: A promising device for linear colliders
The need of intense and bright positron sources for linear colliders has urged the researches on polarized and unpolarized positrons. For 20 years, continuous theoretical and experimental investigations on unpolarized positron sources using axially channelled electrons in aligned monocrystals have pointed to efficient solutions concerning not only the source intensity, but also the minimization of the deposited energy. Simulations using the channelling programme of V. Strakhovenko associated to GEANT4, provided a description of such sources composed of tungsten crystals as photon radiators and amorphous tungsten as converters, the so-called hybrid source; the incident electron energies are taken between 5 and 10 GeV. Here, some applications are shown for CLIC, for which this source is the baseline, and
also for ILC. The simulations are also concerning the test at KEK of such hybrid source, with a sweeping magnet separating the crystal radiator and an amorphous converter. Future developments on the simulation programme are also reported. The main issues for such sources are also analyzed
A Large Hadron Electron Collider at CERN
This document provides a brief overview of the recently published report on
the design of the Large Hadron Electron Collider (LHeC), which comprises its
physics programme, accelerator physics, technology and main detector concepts.
The LHeC exploits and develops challenging, though principally existing,
accelerator and detector technologies. This summary is complemented by brief
illustrations of some of the highlights of the physics programme, which relies
on a vastly extended kinematic range, luminosity and unprecedented precision in
deep inelastic scattering. Illustrations are provided regarding high precision
QCD, new physics (Higgs, SUSY) and electron-ion physics. The LHeC is designed
to run synchronously with the LHC in the twenties and to achieve an integrated
luminosity of O(100) fb. It will become the cleanest high resolution
microscope of mankind and will substantially extend as well as complement the
investigation of the physics of the TeV energy scale, which has been enabled by
the LHC
A Large Hadron Electron Collider at CERN
The physics programme and the design are described of a new collider for particle and nuclear physics, the Large Hadron Electron Collider (LHeC), in which a newly built electron beam of 60 GeV, to possibly 140 GeV, energy collides with the intense hadron beams of the LHC. Compared to the first ep collider, HERA, the kinematic range covered is extended by a factor of twenty in the negative four-momentum squared, Q2, and in the inverse Bjorken x, while with the design luminosity of 1033 cm-2 s-1 the LHeC is projected to exceed the integrated HERA luminosity by two orders of magnitude. The physics programme is devoted to an exploration of the energy frontier, complementing the LHC and its discovery potential for physics beyond the Standard Model with high precision deep inelastic scattering measurements. These are designed to investigate a variety of fundamental questions in strong and electroweak interactions. The LHeC thus continues the path of deep inelastic scattering (DIS) into unknown areas of physics and kinematics. The physics programme also includes electron-deuteron and electron-ion scattering in a (Q21/x) range extended by four orders of magnitude as compared to previous lepton-nucleus DIS experiments for novel investigations of neutron's and nuclear structure, the initial conditions of Quark-Gluon Plasma formation and further quantum chromodynamic phenomena. The LHeC may be realised either as a ring-ring or as a linac-ring collider. Optics and beam dynamics studies are presented for both versions, along with technical design considerations on the interaction region, magnets including new dipole prototypes, cryogenics, RF, and further components. A design study is also presented of a detector suitable to perform high precision DIS measurements in a wide range of acceptance using state-of-the art detector technology, which is modular and of limited size enabling its fast installation. The detector includes tagging devices for electron, photon, proton and neutron detection near to the beam pipe. Civil engineering and installation studies are presented for the accelerator and the detector. The LHeC can be built within a decade and thus be operated while the LHC runs in its high-luminosity phase. It so represents a major opportunity for progress in particle physics exploiting the investment made in the LHC