S. Cialdi

Exploring the WEP with a pulsed cold beam of antihydrogen

The AEGIS experiment, currently being set up at the Antiproton Decelerator at CERN, has the objective of studying the free fall of antimatter in the Earth?s gravitational field by means of a pulsed cold atomic beam of antihydrogen atoms. Both duration of free fall and vertical displacement of the horizontally emitted atoms will be measured, allowing a first test of the WEP with antimatter.

The SPARC project: a high-brightness electron beam source at LNF to drive a SASE-FEL experiment

Abstract The Project Sorgente Pulsata e Amplificata di Radiazione Coerente (SPARC), proposed by a collaboration among ENEA–INFN–CNR–Universita’ di Tor Vergata–INFM–ST, was recently approved by the Italian Government and will be built at LNF. The aim of the project is to promote an R&D activity oriented to the development of a coherent ultra-brilliant X-ray source in Italy. This collaboration has identified a program founded on two main issues: the generation of ultra-high peak brightness electron beams and of resonant higher harmonics in the SASE-FEL process, as presented in this paper.

A moiré deflectometer for antimatter

The precise measurement of forces is one way to obtain deep insight into the fundamental interactions present in nature. In the context of neutral antimatter, the gravitational interaction is of high interest, potentially revealing new forces that violate the weak equivalence principle. Here we report on a successful extension of a tool from atom optics—the moiré deflectometer—for a measurement of the acceleration of slow antiprotons. The setup consists of two identical transmission gratings and a spatially resolving emulsion detector for antiproton annihilations. Absolute referencing of the observed antimatter pattern with a photon pattern experiencing no deflection allows the direct inference of forces present. The concept is also straightforwardly applicable to antihydrogen measurements as pursued by the AEgIS collaboration. The combination of these very different techniques from high energy and atomic physics opens a very promising route to the direct detection of the gravitational acceleration of neutral antimatter.

Experimental estimation of one-parameter qubit gates in the presence of phase diffusion

We address estimation of one-parameter qubit gates in the presence of phase diffusion. We evaluate the ultimate quantum limits to precision, seek optimal probes and measurements, and demonstrate an optimal estimation scheme for polarization encoded optical qubits. An adaptive method to achieve optimal estimation in any working regime is also analyzed in detail and experimentally implemented.

Homodyne detection as a near-optimum receiver for phase-shift-keyed binary communication in the presence of phase diffusion

We address binary optical communication channels based on phase-shift-keyed coherent signals in the presence of phase diffusion. We prove theoretically and demonstrate experimentally that a discrimination strategy based on homodyne detection is robust against this kind of noise for any value of the channel energy. Moreover, we find that a homodyne receiver beats the performance of a Kennedy receiver as the signal energy increases and achieves the Helstrom bound in the limit of large noise.

Optical interferometry in the presence of large phase diffusion

Phase diffusion represents a crucial obstacle towards the implementation of high precision interferometric measurements and phase shift based communication channels. Here we present a nearly optimal interferometric scheme based on homodyne detection and coherent signals for the detection of a phase shift in the presence of large phase diffusion. In our scheme the ultimate bound to interferometric sensitivity is achieved already for a small number of measurements, of the order of hundreds, without using nonclassical light.

Conceptual design of a high-brightness linac for soft X-ray SASE-FEL source

Abstract FELs based on SASE are believed to be powerful tools to explore the frontiers of basic sciences, from physics to chemistry to biology. Intense R&D programs have started in the USA and Europe in order to understand the SASE physics and to prove the feasibility of these sources. The allocation of considerable resources in the Italian National Research Plan (PNR) brought about the formation of a CNR–ENEA–INFN–University of Roma “Tor Vergata” study group. A conceptual design study has been developed and possible schemes for linac sources have been investigated, leading to the SPARX proposal. We report in this paper the results of a preliminary start to end simulation concerning one option we are considering based on an S-band normal conducting linac with high-brightness photoinjector integrated in an RF compressor.

The Project Plasmonx for Plasma Acceleration Experiments and A Thomson X-Ray Source at SPARC

We present the status of the project PLASMONX, recently approved by INFN. This project, based on a collaboration between INFN and CNR-IPCF, aims at a long term upgrade of the SPARC system with the goal to develop at LNF an integrated facility for advanced beam-laser-plasma research in the field of advanced acceleration techniques and ultra-bright X-ray radiation sources and related applications. The project, in its first phase, foresees the development at LNF of a High Intensity Laser Laboratory (HILL) whose main component is a 100 TW-class Ti: Sa laser system synchronized to the SPARC photo-injector. Experiments of self-injection and acceleration of electrons into laser driven plasma waves will be conducted at HILL-LNF, early in this first project phase. Eventually an additional beam line will be built in the SPARC bunker in order to transport the SPARC electron beam at an interaction point, where a final focus system will allow to conduct experiments either of laser-beam co-propagation in plasma waves for high gradient acceleration, or experiments of laser-beam head-on collisions to develop a Thomson source of bright ultra-short X-ray radiation pulses, with X-ray energies tunable in the range 20 to 1000 keV and pulse duration from 30 fs to 20 ps. Preliminary simulations of plasma acceleration with self-injection are illustrated, as well as external injection of the SPARC electron beam.

Two-step procedure to discriminate discordant from classical correlated or factorized states

We devise and experimentally realize a procedure capable of detecting and distinguishing quantum discord and classical correlations as well the presence of factorized states in a joint system-environment setting. Our scheme builds on recent theoretical results showing how the distinguishability between two reduced states of a quantum system in a bipartite setting can convey important information about the correlations present in the bipartite state and the interaction between the subsystems. The two addressed subsystems are the polarization and spatial degrees of freedom of the signal beam generated by parametric down-conversion, which are suitably prepared by the idler beam. Different global and local operations allow for the detection of different correlationsbystudyingviastatetomographythetracedistancebehaviorbetweensuitablepolarizationsubsystem states.

AEgIS experiment commissioning at CERN

The AEgIS Experiment is an international collaboration based at CERN whose aim is to perform the first direct measurement of the gravitational acceleration g of antihydrogen in the gravitational field of the Earth. Cold antihydrogen will be produced with a pulsed charge exchange reaction in a cylindrical Penning trap where antiprotons will be cooled to 100mK. The cold antihydrogen will be produced in an excited Rydberg state and subsequently formed into a beam. The deflection of the antihydrogen beam will be measured by using Moire deflectometer gratings. After being approved in late 2008, AEgIS started taking data in a commissioning phase early 2012. This report presents an overview of the AEgIS experiment, describes its current status and shows the first measurements on antiproton catching and cooling in the 5 T Penning catching trap. We will also present details on the techniques needed for the 100mK antihydrogen production, such as pulsed positronium production and its excitation with lasers.