Detection of multimode spatial correlation in PDC and application to the absolute calibration of a CCD camera

We propose and demonstrate experimentally a new method based on the spatial entanglement for the absolute calibration of analog detector. The idea consists on measuring the sub-shot-noise intensity correlation between two branches of parametric down conversion, containing many pairwise correlated spatial modes. We calibrate a scientific CCD camera and a preliminary evaluation of the statistical uncertainty indicates the metrological interest of the method

Analysis of the possibility of analog detectors calibration by exploiting Stimulated Parametric Down Conversion

Spontaneous parametric down conversion (SPDC) has been largely exploited as a tool for absolute calibration of photon-counting detectors, i.e detectors registering very small photon fluxes. In [J. Opt. Soc. Am. B 23, 2185 (2006)] we derived a method for absolute calibration of analog detectors using SPDC emission at higher photon fluxes, where the beam is seen as a continuum by the detector. Nevertheless intrinsic limitations appear when high-gain regime of SPDC is required to reach even larger photon fluxes. Here we show that stimulated parametric down conversion allow one to avoid this limitation, since stimulated photon fluxes are increased by the presence of the seed beam.Comment: 9 pages, 1 figur

The possibility of absolute calibration of analog detectors by using parametric down-conversion: a systematical study

Accurate calibration of photodetectors both in analog and in photon-counting regime is fundamental for various scientific applications, which range from "traditional" quantum optics to the studies on foundations of quantum mechanics, quantum cryptography, quantum computation, etc. In this paper we systematically study the possibility of the absolute calibration of analog photo-detectors based on the properties of parametric amplifiers. Our results show that such a method can be effectively developed with interesting possible metrological applications

A two regime model of inflation and unemployment fluctuations

In this paper we present a formal definition of the notions of economic regime and regime dynamics. Starting from these definitions, we discuss a multiple regime dynamic model generating an endogenous unemployment-price adjustment mechanism. Two different employment regimes are introduced and the regime dynamics properties of the model are analyzed. Specifically, we assume that the equations governing employment and prices dynamics undergo a discontinuous change in regime when a critical value of unemployment rate is reached. Depending on parameter values, we show that this model is capable of producing a rich variety of dynamic behavior, including complex irregular fluctuations. The main result of this paper is the representation of the regime dynamics via symbolic dynamics. In particular, we show that the regime dynamics of the model can be represented by a shift of finite type that depends on parameter values. In some particular cases, we can also have a representation via directed vertex graphs. An important consequence of this is the possibility of measuring the complexity of the model by using the entropy measure.

The gradient flow coupling from numerical stochastic perturbation theory

Perturbative calculations of gradient flow observables are technically challenging. Current results are limited to a few quantities and, in general, to low perturbative orders. Numerical stochastic perturbation theory is a potentially powerful tool that may be applied in this context. Precise results using these techniques, however, require control over both statistical and systematic uncertainties. In this contribution, we discuss some recent algorithmic developments that lead to a substantial reduction of the cost of the computations. The matching of the ${\overline{\rm MS}}$ coupling with the gradient flow coupling in a finite box with Schr\"odinger functional boundary conditions is considered for illustration.Comment: Talk given at the 34th annual International Symposium on Lattice Field Theory, 24-30 July 2016, University of Southampton, UK; LaTeX source, 7 pages, 2 figure

SMD-based numerical stochastic perturbation theory

The viability of a variant of numerical stochastic perturbation theory, where the Langevin equation is replaced by the SMD algorithm, is examined. In particular, the convergence of the process to a unique stationary state is rigorously established and the use of higher-order symplectic integration schemes is shown to be highly profitable in this context. For illustration, the gradient-flow coupling in finite volume with Schr\"odinger functional boundary conditions is computed to two-loop (i.e. NNL) order in the SU(3) gauge theory. The scaling behaviour of the algorithm turns out to be rather favourable in this case, which allows the computations to be driven close to the continuum limit.Comment: 35 pages, 4 figures; v2: corrected typos, coincides with published versio

Symbolic Time Series Analysis in Economics

In this paper I describe and apply the methods of Symbolic Time Series Analysis (STSA) to an experimental framework. The idea behind Symbolic Time Series Analysis is simple: the values of a given time series data are transformed into a finite set of symbols obtaining a finite string. Then, we can process the symbolic sequence using tools from information theory and symbolic dynamics. I discuss data symbolization as a tool for identifying temporal patterns in experimental data and use symbol sequence statistics in a model strategy. To explain these applications, I describe methods to select the symbolization of the data (Section 2), I introduce the symbolic sequence histograms and some tools to characterize and compare these histograms (Section 3). I show that the methods of symbolic time series analysis can be a good tool to describe and recognize time patterns in complex dynamical processes and to extract dynamical information about this kind of system. In particular, the method gives us a language in which to express and analyze these time patterns. In section 4 I report some applications of STSA to study the evolution of ifferent economies. In these applications data symbolization is based on economic criteria using the notion of economic regime introduced earlier in this thesis. I use STSA methods to describe the dynamical behavior of these economies and to do comparative analysis of their regime dynamics. In section 5 I use STSA to reconstruct a model of a dynamical system from measured time series data. In particular, I will show how the observed symbolic sequence statistics can be used as a target for measuring the goodness of fit of proposed models.

Experimental realization of a low-noise heralded single photon source

We present a heralded single-photon source with a much lower level of unwanted background photons in the output channel by using the herald photon to control a shutter in the heralded channel. The shutter is implemented using a simple field programable gate array controlled optical switch.Comment: 4 pages, 5 figure

Perceived authenticity and museum visitors' behavior: a case of South Tirol's museum of archeology in Bolzano

In this study we analyze perception of authenticity by visitors of South Tyrol's museum of archeology, best known as Otzi museum, in the Autonomous Province of Bolzano (Italy). With the help of factor analysis we individuate two factors related to authenticity and study the determinants of the perception of authenticity by the visitors. Individuated factors are then employed to explain visitors' behavior at the museum. In particular, we study how perception of authenticity is related to the time visitors spend at the museum. Next we investigate the influence of authenticity on shopping behavior of museum visitors. The relevant data were obtained from a survey undertaken in the months from June to August 2010 at site. The empirical findings provide important insights for the management of the Otzi museum.Authenticity, museum management, souvenirs, factor analysis, tobit regression.