9,248 research outputs found

    Full counting statistics of weak measurement

    Full text link
    A weak measurement consists in coupling a system to a probe in such a way that constructive interference generates a large output. So far, only the average output of the probe and its variance were studied. Here, the characteristic function for the moments of the output is provided. The outputs considered are not limited to the eigenstates of the pointer or of its conjugate variable, so that the results apply to any observable \Hat{o} of the probe. Furthermore, a family of well behaved complex quantities, the normal weak values, is introduced, in terms of which the statistics of the weak measurement can be described. It is shown that, within a good approximation, the whole statistics of weak measurement is described by a complex parameter, the weak value, and a real one.Comment: Expanded version: 9 pages, 3 Figs. Now the validity of the expansion for the moments is analysed. Introduced a one-parameter family of weak values, useful to express the correct characteristic function. More figures added. Thanks to Referee C of PRL for asking stimulating question

    Methodological problems in solvency assessment of an insurance company

    Get PDF
    The recent wide development and changes in insurance markets highlighted the necessity to map out the solvency analysis in a more complete framework. The approach we present in the paper comes up with an integrated analysis of the risk profile of an insurance business, taking into account the actual European directives about solvency assessment. The aim of the paper is to construct a methodology apt to incorporate properly the effect of the risk sources in calculating mathematical provisions related to a portfolio of insurance policies.Life insurance, financial risk, demographic risk, capital adequacy, reserves, conditional random processes

    Sequential measurement of conjugate variables as an alternative quantum state tomography

    Full text link
    It is shown how it is possible to reconstruct the initial state of a one-dimensional system by measuring sequentially two conjugate variables. The procedure relies on the quasi-characteristic function, the Fourier-transform of the Wigner quasi-probability. The proper characteristic function obtained by Fourier-transforming the experimentally accessible joint probability of observing "position" then "momentum" (or vice versa) can be expressed as a product of the quasi-characteristic function of the two detectors and that, unknown, of the quantum system. This allows state reconstruction through the sequence: data collection, Fourier-transform, algebraic operation, inverse Fourier-transform. The strength of the measurement should be intermediate for the procedure to work.Comment: v2, 5 pages, no figures, substantial improvements in the presentation, thanks to an anonymous referee. v3, close to published versio

    Separating the North and South Pacific Meridional Modes Contributions to ENSO and Tropical Decadal Variability

    Get PDF
    North and South Pacific Meridional Modes (NPMM and SPMM) are known precursors of El Niño–Southern Oscillation (ENSO) and Tropical Pacific decadal variability (TPDV). However, the relative importance of these precursors and the timescale on which they impact the tropics remain unclear. Using a 30-member ensemble of the Community Earth System Model as the control climate, we generate two additional members where the NPMM and SPMM are selectively suppressed. We find that both meridional modes energize the tropical variance independently on different timescales. The absence of NPMM leads to a significant reduction of the tropical interannual variability (~35%), while the absence of the SPMM has no appreciable impact on ENSO but significantly reduces the TPDV (~30%). While the relative importance of the NPMM and SPMM may be model dependent, the stochastic atmospheric variability in the extratropics that energizes the meridional modes emerges as a key source of TPDV

    Crisi e rimobilitazione: gli italiani, la politica, i partiti nelle indagini campionarie del CISE (2011-2012)

    Get PDF
    Nella primavera 2012, pochi mesi dopo l\u2019insediamento del governo Monti, i partiti italiani toccavano il punto pi\uf9 basso della loro presa sull\u2019opinione pubblica italiana: altissime percentuali di astenuti e indecisi, con un elettorato demotivato da un\u2019offerta politica ancora incerta (anche a causa della difficile convivenza con un governo tecnico) e quindi incapace di strategie innovative. Tuttavia, \ue8 forse vero che la politica ha orrore del vuoto: l\u2019imminenza delle elezioni amministrative (del maggio 2012) e soprattutto l\u2019ingresso nell\u2019ultimo anno prima delle elezioni politiche segnano una ripresa dell\u2019iniziativa politica, sia da parte dei partiti esistenti che da parte di nuovi attori politici. Il primo a muoversi \ue8 il Movimento 5 Stelle, con un\u2019aggressiva strategia per le elezioni amministrative, in cui registrer\ue0 un grande successo. Ma in secondo luogo \ue8 il centrosinistra a gettarsi in una impegnativa e rischiosa strategia politica basata sulle primarie, che otterr\ue0 tuttavia il grande risultato di una significativa rimobilitazione del proprio elettorato. Tutte queste tendenze sono state puntualmente registrate dalla serie di indagini demoscopiche Osservatorio Politico CISE, condotte ogni sei mesi a partire dalla primavera 2011. I risultati di queste indagini, gi\ue0 pubblicati sul sito web Cise nel corso del 2012, sono raccolti oggi in questo secondo Dossier CISE. Una riflessione sul clima di opinione pubblica che conduce alle elezioni politiche del 2013, che vuole fornire dati utili per interpretare le ultime fasi della campagna elettorale e per inquadrare l\u2019ormai imminente risultato delle elezioni

    Risk-adjusted performance indicators in life insurance

    Get PDF
    The paper approaches the potential of risk-adjusted performance indicators in life insurance, with special reference to a structured policy. The final issue is the computation of risk adjusted indicators as a tool to evaluate the portfolio given a policy structure. The computation of such indicator could be suitable for the appraisal of both portfolio optimization and potential profits of the structured policy. The selection tool is put into an asset and liability management decision making context, where the relationship between expected surplus and capital at risk are compared. The analysis is applied to a structured temporary annuity and is treated by means of Monte Carlo simulations
    corecore