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Search Results: 1 - 10 of 86544 matches for " José Roberto Castilho Piqueira "
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Teoria quantica da informa??o: impossibilidade de cópia, entrela?amento e teletransporte
Piqueira, José Roberto Castilho;
Revista Brasileira de Ensino de Física , 2011, DOI: 10.1590/S1806-11172011000400003
Abstract: the idea of developing computers with dynamics obeying quantum mechanics laws comes from the last quarter of 20th century assuming, nowadays, a remarkable technological and scientific importance, as the use of quantum algorithms has been disseminated on implementing cryptography systems and, besides, quantum channel experiments start to become present in the literature. there are, even, conjectures about quantum behaviors in synapses and in other natural phenomena considered to be macroscopic. all these developments are based on quantum information theory that, generally speaking, could be considered an extension of classical information theory, due to shannon, taking into account two peculiar aspects of quantum phenomena: the impossibility of copying a quantum state and the mutual dependence shown by two states originated in their preparation. this work is about these two points without originality intentions, presents the concept of entanglement and the proof of the non-conning theorem. some applications, mixed with fiction, are presented and possible similarity with real facts is a mere coincidence.
N?o-linearidades: da dinamica do simples à dinamica do complexo
Piqueira, José Roberto Castilho;
Trans/Form/A??o , 1994, DOI: 10.1590/S0101-31731994000100011
Abstract: some concepts related to the utilization of dynamical systems theory on complex systems problems are presented. using these concepts, we suggest that two dynamics can be established: a short-term one and a long-term one, and both of them are connected to the system's organization processes.
Biomatemática: métodos e limita??es
Piqueira, José Roberto Castilho;
Trans/Form/A??o , 1996, DOI: 10.1590/S0101-31731996000100009
Abstract: this article tries to give a general vision of the mathematical methods used to model biological processes. there are two kinds of methods: deterministics using dynamical systems theory and probabilistics, using stochastic differential equations. however, three points can not be neglected for biological processes: complexity, unpredictability and diversity of time scales.
O sonho de Bernouilli
Piqueira, José Roberto Castilho;Nahas, Tatiana Rodrigues;
Estudos Avan?ados , 2011, DOI: 10.1590/S0103-40142011000200022
Abstract: this paper presents some ideas about the application of mathematical tools to the study of biological problems, in a historic context. by using the dynamical system theory, some models for biological systems presenting emergence of global complex behavior are discussed.
Auto-organiza??o psíquica
Candido, Carla Laino;Piqueira, José Roberto Castilho;
Psicologia: Reflex?o e Crítica , 2002, DOI: 10.1590/S0102-79722002000300020
Abstract: being animated by a little bit more tension differs the human from non-human, in a psychoanalytic perspective, creating a dynamics in which a new psychiatric reality emerges. taking the body stimulus as dispersion, without providing a structured set and emphasizing a mental semantics based on sexuality, we point out that freud traced a parallel between two different domains: mental sciences and brain sciences, setting the idea of complexity in his theories. in this paper, we try to show the connections between the concepts of drive and unconscious, putting the origins of the signifying in an uncontrollable territory, providing the of understanding of the emergence of psychical life as a self-organizing process of a brain sensitive to initial conditions. small disturbances in the initial conditions are amplified in the global fluctuation and this idea could contribute towards the comprehension of the modern perspectives of the study of the mind.
Auto-organiza o psíquica
Candido Carla Laino,Piqueira José Roberto Castilho
Psicologia: Reflex?o e Crítica , 2002,
Abstract: Sermos animados por um "a mais de tens o" difere o humano do n o-humano na perspectiva psicanalítica, situa o que cria um dinamismo no qual emerge a realidade psíquica. Ao tomar os estímulos corporais como pura dispers o, sem formarem de início um conjunto estruturado e ao enfatizar a existência de uma semantica mental apoiada na sexualidade, apontamos que Freud tra ou um paralelo entre dois domínios diferentes: ciências mentais e ciências do cérebro, incorporando precocemente preceitos de complexidade às suas teorias. Neste artigo, tentamos mostrar que a articula o entre as no es de puls o e de inconsciente, a qual coloca a gênese da significa o em território n o-controlável, possibilitando a compreens o da emergência do psiquismo como um processo de auto-organiza o de um cérebro sensível às condi es iniciais. Perturba es pequenas s o amplificadas na flutua o global e essa idéia pode contribuir para a compreens o das modernas perspectivas de estudo da mente.
Quantum Entanglement Phase Transition in Werner State
Yuri Campbell,José Roberto Castilho Piqueira
Physics , 2011,
Abstract: An extension to computational mechanics complexity measure is proposed in order to tackle quantum states complexity quantification. The method is applicable to any $n-$partite state of qudits through some simple modifications. A Werner state was considered to test this approach. The results show that it undergoes a phase transition between entangled and separable versions of itself. Also, results suggest interplay between quantum state complexity robustness rise and entanglement. Finally, only via symbolic dynamics statistical analysis, the proposed method was able to distinguish separable and entangled dynamical structural differences.
Classical Hierarchical Correlation Quantification on Tripartite Qubit Mixed State Families
Yuri Campbell,José Roberto Castilho Piqueira
Mathematics , 2011,
Abstract: There are at least a number of ways to formally define complexity. Most of them relate to some kind of minimal description of the studied object. Being this one in form of minimal resources of minimal effort needed to generate the object itself. This is usually achieved by detecting and taking advantage of regularities within the object. Regularities can commonly be described in an information-theoretic approach by quantifying the amount of correlation playing a role in the system, this being spatial, temporal or both. This is the approach closely related to the extent that the whole cannot be understood as only the sum of its parts, but also by their interactions. Feature considered to be most fundamental. Nevertheless, this irreducibility, even in the basic quantum informational setting of composite states, is also present due to the intrinsic structure of Hilbert spaces' tensor product. In this approach, this irreducibility is quantified based on statistics of von Neumann measurements forming mutually unbiased bases. Upon two different kinds of tripartite qubit mixed state families, which hold the two possible distinct entangled states on this space. Results show that this quantification is sensible to the different kind of entanglement present on those families.
The Tight Coupling and Non-Linear Relationship between the Macroscopic Electrical and Optical Concomitants of Electrochemical CNS Waves Reflect the Non-Linear Dynamics of Neural Glial Propagation  [PDF]
Vera Maura Fernandes de Lima, José Roberto Castilho Piqueira, Wolfgang Hanke
Open Journal of Biophysics (OJBIPHY) , 2015, DOI: 10.4236/ojbiphy.2015.51001
Abstract: In isolated chick retina, the visualization of electrochemical self-organized patterns is possible due to the presence of macroscopic intrinsic optical signals (IOSs). Isolated circular waves, standing patterns, and self-sustained sequences of spirals are all easily obtained using an IOS approach. In this paper we present the tight coupling and non-linear relationship between optical and electrical wave concomitants, and potassium-induced whole tissue excitability changes. Elementary statistical methods and time series analyses were applied to two sets of data: 1) solitary circular retinal spreading depression waves, and 2) tissue response to exogenous potassium fast pulses. The results were interpreted from the point of view of non-linear thermodynamical concepts and volume phase transitions in polyanionic gels according to the Tasaki action potential model. From these and previous results, it is clear that the glial network and extracellular matrix contribute to the propagation and emergence of these patterns.
Models for Master-Slave Clock Distribution Networks with Third-Order Phase-Locked Loops
José Roberto Castilho Piqueira,Marcela de Carvalho Freschi
Mathematical Problems in Engineering , 2007, DOI: 10.1155/2007/18609
Abstract: The purpose of this work is to study the processing and transmission of clock signals in networks of geographically distributed nodes, in order to derive conditions for frequency and phase synchronization between the nodes. The focus is on the master-slave architecture, which presents a priority scheme of clock distribution. One-way master-slave (OWMS ) and two-way master-slave (TWMS) chains are studied, considering that the slave nodes are third-order phase-locked loops (PLLs). Third-order PLLs are chosen to improve the transient response but, if their parameters are not well adjusted, stability problems and chaotic behaviors appear, restricting the lock-in range of the network. Lock-in range for third-order PLLs with Sallen-Key filter is determined and it is verified whether this range is reduced when the PLLs are connected to a network. Numerical experiments show how chain size changes the lock-in ranges and the acquisition times.
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