Self-consistent characterization of light statistics

We demonstrate the possibility of a self-consistent characterization of the photon-number statistics of a light field by using photoemissive detectors with internal gain simply endowed with linear input/output responses. The method can be applied to both microscopic and mesoscopic photon-number regimes. The detectors must operate in the linear range without need of photon-counting capabilities.Comment: To be published in "Journal of Modern Optics

Multiphoton communication in lossy channels with photon-number entangled states

We address binary and quaternary communication channels based on correlated multiphoton two-mode states of radiation in the presence of losses. The protocol are based on photon number correlations and realized upon choosing a shared set of thresholds to convert the outcome of a joint photon number measurement into a symbol from a discrete alphabet. In particular, we focus on channels build using feasible photon-number entangled states (PNES) as two-mode coherently-correlated (TMC) or twin-beam (TWB) states and compare their performances with that of channels built using feasible classically correlated (separable) states. We found that PNES provide larger channel capacity in the presence of loss, and that TWB-based channels may transmit a larger amount of information than TMC-based ones at fixed energy and overall loss. Optimized bit discrimination thresholds, as well as the corresponding maximized mutual information, are explicitly evaluated as a function of the beam intensity and the loss parameter. The propagation of TMC and TWB in lossy channels is analyzed and the joint photon number distribution is evaluated, showing that the beam statistics, either sub-Poissonian for TMC or super-Poissonian for TWB, is not altered by losses. Although entanglement is not strictly needed to establish the channels, which are based on photon-number correlations owned also by separable mixed states, purity of the support state is relevant to increase security. The joint requirement of correlation and purity individuates PNES as a suitable choice to build effective channels. The effects of losses on channel security are briefly discussed.Comment: 8 pages, 19 figure

Statistical analysis on testing of an entangled state based on Poisson distribution framework

A hypothesis testing scheme for entanglement has been formulated based on the Poisson distribution framework instead of the POVM framework. Three designs were proposed to test the entangled states in this framework. The designs were evaluated in terms of the asymptotic variance. It has been shown that the optimal time allocation between the coincidence and anti-coincidence measurement bases improves the conventional testing method. The test can be further improved by optimizing the time allocation between the anti-coincidence bases.Comment: This paper is an extended version of the theoretical part of v1 of quant-ph/0603254.quant-ph/0603254 is revised so that it is more familiar to experimentalist

Measurement of two-mode squeezing with photon number resolving multi-pixel detectors

The measurement of the two-mode squeezed vacuum generated in an optical parametric amplifier (OPA) was performed with photon number resolving Multi-Pixel Photon Counters (MPPCs). Implementation of the MPPCs allows for the observation of noise reduction in a broad dynamic range of the OPA gain, which is inaccessible with standard single photon avalanche photodetectors.Comment: Accepted for Optics Letter

Programmazione e controllo

Il libro è l'edizione italiana di un testo, giunto ormai alla sua 13° edizione, di un classico della disciplina di programmazione e controllo

L'evoluzione della Funzione Amministrativa. Attività, professionalità e assetti nell'era dell'integrazione informativa

Il lavoro analizza l'impatto dell'integrazione informativa sulla funzione amministrativa, in relazione alla gestione delle attività, alla professionalità e agli assetti operativi. La ricerca pone in evidenza come la realizzazione dei benefici promessi dall'integrazione informativa dipenda in ultima analisi dalla capacità dei professionisti dell'amministrazione di estrarre il potenziale messo a disposizione dai sistemi informativi integrati

The PROMEHS project: a comprehensive multi-component curriculum to promote mental health in schools

Mental health is defined as a state of well-being in which every individual realizes his or her own potential, copes with the normal stresses of life, works productively and fruitfully, and is able to make a contribution to her or his community (WHO, 2014). Mental health problems among children have been increasing over the past decades. This underlines the urgent need for early intervention, with schools providing a unique opportunity for the promotion of mental health of students. This study describes the goals and methodology of PROMEHS, a European project aimed to develop an evidence-based curriculum to promote mental health at school. PROMEHS will also promote innovation in educational policies in collaboration with national and international public authorities. PROMEHS will be implemented in six European Countries using the training study methodology. The research design includes the collection of pre- and post-test data among students and their teachers from kindergarten to secondary school. Comparison between the experimental group and the control group will be carried out in order to assess the impact of the PROMEHS curriculum. The findings and outcomes will then serve as the basis for national educational policies in the Member States on mental health promotion in school

Quantum and classical correlations of intense beams of light investigated via joint photodetection

We address joint photodetection as a method for discriminating between the classical correlations of a thermal beam divided by a beam splitter and the quantum entanglement of a twin beam obtained by parametric down-conversion. We show that for intense beams of light the detection of the difference photocurrent may be used, in principle, in order to reveal entanglement, while the simple measurement of the correlation coefficient is not sufficient. We have experimentally measured the correlation coefficient and the variance of the difference photocurrent for several classical and quantum states. Results are in good agreement with theoretical predictions taking into account the extra noise in the generated fields that is due to the pump laser fluctuations