1,721,048 research outputs found
Quantum jump as an objective process of nature
No full textWe study the time evolution of a linear superposition of two spatially separated wave packets, and we focus on the entanglement of the two distinct branches of the state vector with the environment. We focus in particular on the dynamics of a dissipative oscillator under the influence of objective processes of wave-function collapse, the continuous spontaneous localizations (CSL) recently proposed by Ghirardi et al. [G. C. Ghirardi, P. Pearle, and A. Rimini, Phys. Rev. A 42, 78 (1990)]. We prove that the entanglement of the system of interest with the environment induces an accumulation of spontaneous wave-function collapses denoted by us as the environment-enhanced CSL process. This process of CSL accumulation is triggered by the same mechanism of interaction between the quantum system and the environment as that responsible for relaxation and dissipation. In agreement with the predictions of a preceding paper of our group [D. Vitali, L. Tessieri, and P. Grigolini, Phys. Rev. A 50, 967 (1994)], the CSL processes are shown to produce negligible effects at the statistical level. However, if we assume the attitude stimulated by the recent literature on optical quantum jumps, which is forcing us to adopt individual-system pictures, we show that the single runs are characterized by processes of wave-function collapses occurring at times compatible in principle with the experimental observation
Emergence and Exploitation of Collective Intelligence of Groups
Full text linkThis dissertation deals with the emergence and exploitation of the collective intelligence of human groups. The first part of the work (chapter 2) aims to review the mechanisms beyond the swarming behaviors in natural systems, focusing on their properties, potentialities, and limitations, as well as providing the state of the art in the developing field of swarm robotics. In chapter 3, some of the most known biologically inspired optimization algorithms, are introduced, highlighting their variants, merits and drawbacks.
In chapter 4, the author introduces a new decision-making model (DMM), firstly proposed by Carbone and Giannoccaro (Carbone & Giannoccaro, 2015) for solving complex combinatorial problems, showing a detailed analysis of its features and potentialities.
In Chapter 5 an application of the DMM to the simulation of a management problem, easily adaptable to the simulation of any kind of social decision-making problems, is reported.
In chapter 6 the author introduces a novel optimization algorithm belonging to the class of swarm intelligence optimization methods. The proposed algorithm, referred as Human Group Optimization algorithm (HGO), is developed within the previously mentioned DMM (Carbone & Giannoccaro, 2015) and emulates the collective decision making process of human groups. To test the ability of the HGO algorithm, we compare its performance with those of the Simulated Annealing (SA), and Genetic Algorithm (GA) in solving NP-complete problems, consisting in finding the optimum on a fitness landscape, the latter generated within the Kauffman NK model of complexity.
Chapter 8 contains all the mathematical tools and the basic notions, necessary to a complete understanding of the models and procedures mentioned in the work
ON THE CONTRACTION OF FAST VARIABLES IN STOCHASTIC-PROCESSES - THE INFLUENCE OF PUMPING ON RELAXATION
No full textN/
Non-gaussian distributions in computer triatomics
No full textA molecular dynamics simulation of 108 triatomic molecules of C2v symmetry reveals markedly non-gaussian statistical distributions of vectors such as the centre-of-mass linear velocity, molecular angular momentum, positional and orientational coordinates. The results are reproduced qualitatively in the case of linear velocity by a straightforward extension of the Fokker-Planck equation
BEYOND THE SEMICLASSICAL APPROXIMATION OF THE DISCRETE NONLINEAR SCHRODINGER-EQUATION - COLLAPSES AND REVIVALS AS A SIGN OF QUANTUM FLUCTUATIONS
No full textThe mutual interaction of molecular rotation and translation
No full textThe dynamics of molecular rototranslation are treated with an equation of motion with a non-Markovian, stochastic force/torque. It is shown that this Mori/Kubo/Zwanzig representation is equivalent to a multidimensional Markov equation which may be identified with analytical models of the molecular motion. Langevin and Fokker-Planck equations for two such models are derived from the general equations of motion. The analytical results are compared with a computer simulation of the velocity/angular velocity mixed autocorrelation function, C vω ( t ) = v (0) . ω( t )> for a triatomic of C 2 v symmetry
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