arXiv subjects

S. Montangero

Publications and source records attributed to S. Montangero.

40 records · Page 3Linked to original sources

arXiv2003

A study of Complexity in Gamma Ray Burst using the Diffusion Entropy Approach

The Diffusion Entropy algorithm is a method that allows the study of correlated non stationary time series and allows the discrimination between signal and uncorrelated noise. DE provides a quantitative measure of the complexity by means of a scaling index delta. The aim of this paper is to apply this method to study and statistically characterize Gamma-Ray Burst light curves and to introduce a method to constrain and test GRB models.

astro-ph↗

arXiv2003

Measurement and Information Extraction in Complex Dynamics Quantum Computation

We address the problem related to the extraction of the information in the simulation of complex dynamics quantum computation. Here we present an example where important information can be extracted efficiently by means of quantum simulations. We show how to extract efficiently the localization length, the mean square deviation and the system characteristic frequency. We show how this methods work on a dynamical model, the Sawtooth Map, that is characterized by very different dynamical regimes: from near integrable to fully developed chaos; it also exhibits quantum dynamical localization.

quant-ph↗

arXiv2002

Statistical properties of eigenvalues for an operating quantum computer with static imperfections

We investigate the transition to quantum chaos, induced by static imperfections, for an operating quantum computer that simulates efficiently a dynamical quantum system, the sawtooth map. For the different dynamical regimes of the map, we discuss the quantum chaos border induced by static imperfections by analyzing the statistical properties of the quantum computer eigenvalues. For small imperfection strengths the level spacing statistics is close to the case of quasi-integrable systems while above the border it is described by the random matrix theory. We have found that the border drops exponentially with the number of qubits, both in the ergodic and quasi-integrable dynamical regimes of the map characterized by a complex phase space structure. On the contrary, the regime with integrable map dynamics remains more stable against static imperfections since in this case the border drops only algebraically with the number of qubits.

quant-ph↗

arXiv1999

The non-extensive version of the Kolmogorov-Sinai entropy at work

We address the problem of applying the Kolmogorov-Sinai method of entropic analysis, expressed in a generalized non-extensive form, to the dynamics of the logistic map at the chaotic threshold, which is known to be characterized by a power law rather than exponential sensitivity to initial conditions. The computer treatment is made difficult, if not impossible, by the multifractal nature of the natural invariant distribution: Thus the statistical average is carried out on the power index. The resulting entropy time evolution becomes a smooth and linear function of time with the non-extensive index Q < 1 prescribed by the heuristic arguments of earlier work, thereby showing how to make the correct entropic prediction in the spirit of the single-trajectory approach of Kolmogorov.

cond-mat↗