Dynamically localized systems: entanglement exponential sensitivity and efficient quantum simulations

We study the pairwise entanglement present in a quantum computer that simulates a dynamically localized system. We show that the concurrence is exponentially sensitive to changes in the Hamiltonian of the simulated system. Moreover, concurrence is exponentially sensitive to the ``logic'' position of the qubits chosen. These sensitivities could be experimentally checked efficiently by means of quantum simulations with less than ten qubits. We also show that the feasibility of efficient quantum simulations is deeply connected to the dynamical regime of the simulated system.Comment: 5 pages, 6 figure

Fractal Fidelity as a signature of Quantum Chaos

We analyze the fidelity of a quantum simulation and we show that it displays fractal fluctuations iff the simulated dynamics is chaotic. This analysis allows us to investigate a given simulated dynamics without any prior knowledge. In the case of integrable dynamics, the appearance of fidelity fractal fluctuations is a signal of a highly corrupted simulation. We conjecture that fidelity fractal fluctuations are a signature of the appearance of quantum chaos. Our analysis can be realized already by a few qubit quantum processor.Comment: 5 pages, 5 figure

Problematizações das práticas psi : articulações com o pensamento foucaultiano

A problematização das práticas de intervenção na área psi tem sido orientada, muitas vezes, por alguns conceitos foucaultianos como poder, saber e regimes de verdade e tem introduzido questões diferenciadas em relação àquelas que tradicionalmente tem-se caracterizado como uma compreensão do que são as práticas psicológicas. Se por um lado essas reflexões passam por uma desacomodação produzidas pelo olhar foucaultiano, por outro lado, esse incômodo é suscitado pelas práticas psicológicas tradicionais que desfrutam de um estatuto de legitimidade. Esses questionamentos instigam o pensar sobre deslocamentos nas formas de intervenção e compreensão das práticas psi.The problematization of the practices of intervention in Psychology has been helped by foucauldian concepts such as power, knowledge, and truth regimes. These concepts have altered the questions which have traditionally characterized views of psychological practices. However, such analysis has been accused of focusing only on the condition of visibility of power relations and modes of production of truth regimes, instead of instituting new forms of action or intervention. In this article we aim to produce a space for new links between foucauldian thought and current ways of conceiving the interventions in the psychology field

On the Joint Distribution of Energy Levels of Random Schroedinger Operators

We consider operators with random potentials on graphs, such as the lattice version of the random Schroedinger operator. The main result is a general bound on the probabilities of simultaneous occurrence of eigenvalues in specified distinct intervals, with the corresponding eigenfunctions being separately localized within prescribed regions. The bound generalizes the Wegner estimate on the density of states. The analysis proceeds through a new multiparameter spectral averaging principle

Massive young clusters in the disc of M31

We have studied the properties of a sample of 67 very blue and likely young massive clusters in M31 extracted from the Bologna Revised Catalog of globular clusters, selected according to their color [(B-V) < 0.45] and/or to the strength of their Hbeta spectral index (Hbeta > 3.5 A). Their existence in M31 has been noted by several authors in the past; we show here that these Blue Luminous Compact Clusters (BLCCs) are a significant fraction (>~ 15%) of the whole globular cluster system of M31. Compared to the global properties of the M31 globular cluster system, they appear to be intrinsically fainter, morphologically less concentrated, and with a shallower Balmer jump and enhanced $H\beta$ absorption in their spectra. Empirical comparison with integrated properties of clusters with known age as well as with theoretical SSP models consistently indicate that their typical age is less than ~2 Gyr, while they probably are not so metal-poor as deduced if considered to be old. Either selecting BLCCs by their (B-V) colors or by the strength of their Hbeta index the cluster sample turns out to be distributed onto the outskirts of M31 disc, sharing the kinematical properties of the thin, rapidly rotating disc component. If confirmed to be young and not metal-poor, these clusters indicate the occurrence of a significant recent star formation in the thin disc of M31, although they do not set constraints on the epoch of its early formation.Comment: Submitted for publication in the Astronomical Journal. Aastex Latex file of 22 pages, 12 figures and 3 table

Constraining the Cratering Chronology of Vesta

Vesta has a complex cratering history, with ancient terrains as well as recent large impacts that have led to regional resurfacing. Crater counts can help constrain the relative ages of different units on Vesta's surface, but converting those crater counts to absolute ages requires a chronology function. We present a cratering chronology based on the best current models for the dynamical evolution of asteroid belt, and calibrate it to Vesta using the record of large craters on its surface. While uncertainties remain, our chronology function is broadly consistent with an ancient surface of Vesta as well as other constraints such as the bombardment history of the rest of the inner Solar System and the Ar-Ar age distribution of howardite, eucrite and diogenite (HED) meteorites from Vesta.Comment: Accepted to Planetary and Space Science on May 1, 201

SiPM and front-end electronics development for Cherenkov light detection

The Italian Institute of Nuclear Physics (INFN) is involved in the development of a demonstrator for a SiPM-based camera for the Cherenkov Telescope Array (CTA) experiment, with a pixel size of 6$\times$6 mm$^2$. The camera houses about two thousands electronics channels and is both light and compact. In this framework, a R&D program for the development of SiPMs suitable for Cherenkov light detection (so called NUV SiPMs) is ongoing. Different photosensors have been produced at Fondazione Bruno Kessler (FBK), with different micro-cell dimensions and fill factors, in different geometrical arrangements. At the same time, INFN is developing front-end electronics based on the waveform sampling technique optimized for the new NUV SiPM. Measurements on 1$\times$1 mm$^2$, 3$\times$3 mm$^2$, and 6$\times$6 mm$^2$ NUV SiPMs coupled to the front-end electronics are presentedComment: In Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions at arXiv:1508.0589

Hamiltonian analysis of subcritical stochastic epidemic dynamics

We extend a technique of approximation of the long-term behavior of a supercritical stochastic epidemic model, using the WKB approximation and a Hamiltonian phase space, to the subcritical case. The limiting behavior of the model and approximation are qualitatively different in the subcritical case, requiring a novel analysis of the limiting behavior of the Hamiltonian system away from its deterministic subsystem. This yields a novel, general technique of approximation of the quasistationary distribution of stochastic epidemic and birth-death models, and may lead to techniques for analysis of these models beyond the quasistationary distribution. For a classic SIS model, the approximation found for the quasistationary distribution is very similar to published approximations but not identical. For a birth-death process without depletion of susceptibles, the approximation is exact. Dynamics on the phase plane similar to those predicted by the Hamiltonian analysis are demonstrated in cross-sectional data from trachoma treatment trials in Ethiopia, in which declining prevalences are consistent with subcritical epidemic dynamics