marco pettini
Aix-Marseille University, Centre de Physique Théorique, Faculty Member
The nonlinear propagation of a linearly polarized Alfvén wave along a uniform magnetic field is studied taking into account the back reaction of sound oscillations that have been excited by the wave itself. The Alfvén wave propagates... more
The nonlinear propagation of a linearly polarized Alfvén wave along a uniform magnetic field is studied taking into account the back reaction of sound oscillations that have been excited by the wave itself. The Alfvén wave propagates through a uniform, viscous, resistive, magnetized and weakly compressible plasma in typical astrophysical conditions. The back reaction mechanism yields a nonlinear cascade of Alfvén waves on small length scales. The discovered results are very promising with respect to the turbulent heating problem where the laminar heating is negligible.
Research Interests: Physics, Magnetohydrodynamics, Turbulence, Magnetic field, Numerical Simulation, and 14 morePower Law, Asic, Oscillations, Wave Equation, Wave propagation, Compressibility, Length scale, Nonlinear system, Large Scale, Reaction Mechanism, Velocity Field, Solar Corona, Magnetohydrodynamic Turbulence, and Springer Ebooks
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... (ricevuto il 31 Maggie 1985) PACS. 03.20. ... (4) JD MEISS, JR CARY, C. GREBOGI, JD CRAWFORD, AN KA~'FMAN and HDI ABAtC-BANEL: Physica D, 6, 375 (1983). (s) C, F. ~'. ]KARNEy: Physica D, 8, 360 (1983); F. VIVALDI, G.... more
... (ricevuto il 31 Maggie 1985) PACS. 03.20. ... (4) JD MEISS, JR CARY, C. GREBOGI, JD CRAWFORD, AN KA~'FMAN and HDI ABAtC-BANEL: Physica D, 6, 375 (1983). (s) C, F. ~'. ]KARNEy: Physica D, 8, 360 (1983); F. VIVALDI, G. CASATI and I. GUARNERII Phys. Rev. ...
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As in many physical and non physical systems chaos can have harmful consequences, the possibility is discussed of reducing or suppressing it without radically modifying the system.
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Research Interests: Stochastic Process, Physics, Statistical Physics, Fractals, Stochastic processes, and 13 moreMathematical Sciences, Correlation, Diffusion, Physical sciences, Fractal, Invariance, Port Hamiltonian system, Nonlinear system, Fractal Dimension, Degree of Freedom, Nonlinear Equations, Physics Letters A, and nonlinear equation
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Modelling, analysis and computation in phenomenological theories, C. Lo Surdo in quest of the biological soliton - the acetanilide case, A. Tenenbaum molecular dynamics and material science, V. Rosato and A. Ventura electron dynamics and... more
Modelling, analysis and computation in phenomenological theories, C. Lo Surdo in quest of the biological soliton - the acetanilide case, A. Tenenbaum molecular dynamics and material science, V. Rosato and A. Ventura electron dynamics and transport simulations in the linear and nonlinear response domain, F. Cleri numerical simulations of high dimensional Hamiltonian dynamics, M. Pettini and M. Cerruti-Sola n-body simulations of collisionless gravitating systems, A. Messina numerical simulation of compressible MHD turbulance, P. Londrillo numerical techniques for semi-implicit MHD spectral codes, F. Rubini and F. Malara microscopic and mesoscopic simulations of complex flows with cellular automata and related techniques, S. Succi et al nonlinear systems and climate dynamics, R. Legnani synergetic applications of complex ordered processes, I. Purica classifier systems as dynamical systems, R. Serra stochastic processes and analog simulation, L. Fronzoni and F. Cappello parallel architectures for simulations of complex systems, A. Mathis.
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Introduction In psychotherapy, the object of study is not directly perceptible and material, but involves human mind complexity and specific content Objectives In psychotherapeutic relationship we propose a method to inspect by deduction... more
Introduction In psychotherapy, the object of study is not directly perceptible and material, but involves human mind complexity and specific content Objectives In psychotherapeutic relationship we propose a method to inspect by deduction non-conscious mind, patient hidden mood, hate, affectivity. Aims The aim of this work is using a modern physics research method in psychotherapy, in order to focus on what is not directly perceptible in clinical practice. Methods We can examine, instead of 'inductive method”, the 'deductive method”, adapted from physics theoretical approach. We have taken into consideration 'Human Birth Theory”, formulated in 1971 by psychiatrist Fagioli. The author conceived the beginning of human life as a neuropsyche reaction to light. Given the intrauterine dark, Fagioli deducted that brain at birth are activated by 'the absolutely new stimulus”, light. He also deducted 'vitality” and 'capability to imagine” as non-conscious mind features. We have checked recent neurobiological data in literature. Results Functional maturation of 'subplate zone”, light-inducted Immediate Early Genes activation, SATs variations, from foetus to newborn, retina instant activation by photon, 'viability” support Fagioli’s theory. Conclusions In relativistic physics and quantum field theory, deduction is finalised to discover hidden processes, in order to know the primum movens, not perceptible. In psychodynamic psychotherapy, the object par excellence is not just brain, like in neurology, but psyche. Its content is not directly knowable, but can be known also by deductive method, involving intuition, together perception of patient. In psychotherapy physics method can be applied, to discover the non-conscious thought, previous to pathological behaviour. Clinical examples can be reported.
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The preceding Comment [Cuadros and Chacón, Phys. Rev. E 47, 4628 (1993)] on the paper by Lima and Pettini [Phys. Rev. A 41, 726 (1990)] contains a correct premise; however, erroneous consequences are drawn from it. In this Reply we... more
The preceding Comment [Cuadros and Chacón, Phys. Rev. E 47, 4628 (1993)] on the paper by Lima and Pettini [Phys. Rev. A 41, 726 (1990)] contains a correct premise; however, erroneous consequences are drawn from it. In this Reply we explain why. ... (Some reference links ...
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Abstract The absorption spectrum of neutral atomic iodine has been photographed in the EUV region and three strong autoionized resonances have been identified. A broad absorption feature has been observed and is ascribed to a collective... more
Abstract The absorption spectrum of neutral atomic iodine has been photographed in the EUV region and three strong autoionized resonances have been identified. A broad absorption feature has been observed and is ascribed to a collective excitation of the 4d inner shell.
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This paper aims at determining the validity limits of a linear analysis for a resistive instability. To this purpose, the effects of mode-coupling on the magnetic field structure are investigated in the reconnecting layer. Given an... more
This paper aims at determining the validity limits of a linear analysis for a resistive instability. To this purpose, the effects of mode-coupling on the magnetic field structure are investigated in the reconnecting layer. Given an equilibrium magnetic field and a perturbation field, the conditions are found under which the equations for the magnetic field lines of force can be expressed in Hamiltonian form. These conditions can be fulfilled by a resistive instability. Consequently, in a simple equilibrium magnetic field the resistive eigenmodes have been analytically derived. This result is used to give an explicit expression of the Hamiltonian for field-line equations when two resistive eigenmodes are taken into account. The analytical form of the resulting Hamiltonian coincides with the so-called paradigm Hamiltonian (1·5 degrees of freedom) for which the Escande–Doveil renormalization procedure leads to an explicit expression for the global stochasticity threshold. Thus it can b...
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The absence of ergodicity is investigated analytically and numerically for classical field theories and for Euler equations in two dimensions. In the latter case the arguments of Patrascioiu (1984) are extended to the inviscid... more
The absence of ergodicity is investigated analytically and numerically for classical field theories and for Euler equations in two dimensions. In the latter case the arguments of Patrascioiu (1984) are extended to the inviscid two-dimensional fluid dynamical case. The risks of truncation introduced by a numerical simulation of continuous systems reflecting on the analytical properties of the solution of the field equation are discussed. It appears that ergodicity is a property only of the discretized problem. Results are tested on a simple model of a radiant cavity, which shows the absence of the ultraviolet catastrophe and the possibility of wrong interpretations of numerical simulations of field theory.
Research Interests: Field Theory, Ergodic Theory, Physics, Statistical Mechanics, Fluid Dynamics, and 11 moreNumerical Simulation, Mathematical Sciences, Ultraviolet, Classical Field Theory, Physical sciences, Unknown, Euler Lagrange Equation, Boltzmann Transport Equation, Two Dimensions, Continuous System, and Euler Equation
A concise account is given of the early motivations for introducing parametric methods to achieve control of chaos. The heuristic argument that made us think that this kind of method could have been successful is also given. A key study... more
A concise account is given of the early motivations for introducing parametric methods to achieve control of chaos. The heuristic argument that made us think that this kind of method could have been successful is also given. A key study is then reviewed. This concerns a parametric perturbation of a damped and forced Duffing–Holmes oscillator in a chaotic regime. The theoretical analysis, based on the Melnikov treatment of homoclinic tangles, provides a clear understanding of the intimate mechanism that controls chaos. Numerical results confirm and extend the theoretical predictions. A brief discussion of an experimental test on a magneto-elastic device is finally presented.
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International audienc
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Research Interests: Physics, Thermodynamics, Hamiltonian dynamics, Medicine, Phase transition, and 10 morePhysical, Nonlinear Dynamics and Chaos, Temperature Dependence, Quantum and classical statistical mechanics, Phase Space, Lyapunov exponent, Three Dimensional, Numerical computation, Largest Lyapunov Exponent Test, and Geometric mean
A central issue of the science of complex systems is the quantitative characterization of complexity. In the present work a new entropic measure of complexity is proposed which has unprecedented advantages. Starting from the framework of... more
A central issue of the science of complex systems is the quantitative characterization of complexity. In the present work a new entropic measure of complexity is proposed which has unprecedented advantages. Starting from the framework of the so-called information geometry we propose a new and constructive way to associate to a - in principle any - network a differentiable object (a Riemannian manifold) whose volume is used to define an entropy. The effectiveness of this new entropic measure of networks complexity is successfully proved through its capability of detecting a classical phase transition in random graphs: the emergence of the "giant component" according to the celebrated Erdös-Rényi theorem.
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We prove a theorem that establishes a necessary topological condition for the occurrence of first or second order phase transitions; in order for these to occur, the topology of certain submanifolds of configuration space must necessarily... more
We prove a theorem that establishes a necessary topological condition for the occurrence of first or second order phase transitions; in order for these to occur, the topology of certain submanifolds of configuration space must necessarily change at the phase transition point. The theorem applies to a wide class of smooth, finite-range and confining potentials V bounded below, describing systems confined in finite regions of space with continuously varying coordinates. The relevant configuration space submanifolds are the level sets {Σv: = V −1 N (v)}v∈R of the potential function V, N is the number of degrees of freedom and v is the potential energy. The proof proceeds by showing that, under the assumption of diffeomorphicity of the equipotential hypersurfaces {Σv}v∈R in an arbitrary interval of values for v, the Helmoltz free energy is uniformly convergent in N to its thermodynamic limit, at least within the class of twice differentiable functions, in the corresponding interval of t...
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By resorting to a model inspired to the standard Davydov and Holstein-Fröhlich models, in the present paper we study the motion of an electron along a chain of heavy particles modeling a sequence of nucleotides proper to a DNA fragment.... more
By resorting to a model inspired to the standard Davydov and Holstein-Fröhlich models, in the present paper we study the motion of an electron along a chain of heavy particles modeling a sequence of nucleotides proper to a DNA fragment. Starting with a model Hamiltonian written in second quantization, we use the Time Dependent Variational Principle to work out the dynamical equations of the system. It can be found that, under the action of an external source of energy transferred to the electron, and according to the excitation site, the electron current can display either a broad frequency spectrum or a sharply peaked frequency spectrum. This sequence-dependent charge transfer phenomenology is suggestive of a potentially rich variety of electrodynamic interactions of DNA molecules under the action of electron excitation. This could imply the activation of interactions between DNA and transcription factors, or between DNA and external electromagnetic fields.
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In the present paper we address the problem of the energy downconversion of the light absorbed by a protein into its internal vibrational modes. We consider the case in which the light receptors are fluorophores either naturally... more
In the present paper we address the problem of the energy downconversion of the light absorbed by a protein into its internal vibrational modes. We consider the case in which the light receptors are fluorophores either naturally co-expressed with the protein or artificially covalently bound to some of its amino acids. In a recent work [Phys. Rev. X 8, 031061 (2018)], it has been experimentally found that by shining a laser light on the fluorophores attached to a protein the energy fed to it can be channeled into the normal mode of lowest frequency of vibration thus making the subunits of the protein coherently oscillate. Even if the phonon condensation phenomenon has been theoretically explained, the first step - the energy transfer from electronic excitation into phonon excitation - has been left open. The present work is aimed at filling this gap.
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s Book Understanding COMPLEXITY and CONCURRENCY through TOPOLOGY of DATA 2nd EATCS joint with TOPDRIM YOUNG RESEARCHERS SCHOOL & TOPDRIM WORKSHOP Emanuela Merelli (Editor) Camerino 13-22 July 2015
In the present paper we address the problem of the energy downconversion of the light absorbed by a protein into its internal vibrational modes. We consider the case in which the light receptors are fluorophores either naturally... more
In the present paper we address the problem of the energy downconversion of the light absorbed by a protein into its internal vibrational modes. We consider the case in which the light receptors are fluorophores either naturally co-expressed with the protein or artificially covalently bound to some of its amino acids. In a recent work [Phys. Rev. X 8, 031061 (2018)], it has been experimentally found that by shining a laser light on the fluorophores attached to a protein the energy fed to it can be channeled into the normal mode of lowest frequency of vibration thus making the subunits of the protein coherently oscillate. Even if the phonon condensation phenomenon has been theoretically explained, the first step - the energy transfer from electronic excitation into phonon excitation - has been left open. The present work is aimed at filling this gap.
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The phase transition in the mean-field XY model is shown analytically to be related to a topological change in its configuration space. Such a topology change is completely described by means of Morse theory allowing a computation of the... more
The phase transition in the mean-field XY model is shown analytically to be related to a topological change in its configuration space. Such a topology change is completely described by means of Morse theory allowing a computation of the Euler characteristic--of suitable submanifolds of configuration space--which shows a sharp discontinuity at the phase transition point, also at finite N. The present analytic result provides, with previous work, a new key to a possible connection of topological changes in configuration space as the origin of phase transitions in a variety of systems.
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Agent-based modelling and simulation have been effectively applied to the study of complex biological systems, especially when composed by a large number of interacting entities. Representing biomolecules as autonomous agents allows this... more
Agent-based modelling and simulation have been effectively applied to the study of complex biological systems, especially when composed by a large number of interacting entities. Representing biomolecules as autonomous agents allows this approach to bring out the global behaviour of biochemical processes as resulting from local molecular interactions. In this paper, we leverage the capabilities of the agent paradigm to construct an in silico replica of the glycolytic pathway of baker’s yeasts; the aim is to detect the role that long-range electrodynamic forces might have on the rate of glucose oxidation. Experimental evidences have shown that random encounters and short-range potentials might not be sufficient to explain the high efficiency of biochemical reactions in living cells. However, while the latest in vitro studies are limited by the present-day technology, agent-based simulations provide an in silico support to the outcomes hitherto obtained and shed light on behaviours no...
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In the present work we intend to investigate how to detect the behaviour of the immune system reaction to an external stimulus in terms of phase transitions. The immune model considered follows Jerne’s idiotypic network theory. We... more
In the present work we intend to investigate how to detect the behaviour of the immune system reaction to an external stimulus in terms of phase transitions. The immune model considered follows Jerne’s idiotypic network theory. We considered two graph complexity measures—the connectivity entropy and the approximate von Neumann entropy—and one entropy for topological spaces, the so-called persistent entropy. The simplicial complex is obtained enriching the graph structure of the weighted idiotypic network, and it is formally analyzed by persistent homology and persistent entropy. We obtained numerical evidences that approximate von Neumann entropy and persistent entropy detect the activation of the immune system. In addition, persistent entropy allows also to identify the antibodies involved in the immune memory.