1,721,008 research outputs found
On certain canonoid transformations and invariants for the parametric oscillator
No full textIn classical mechanics a transformation in phase space is said to be canonoid if it maps only some Hamiltonian systems into Hamiltonian systems. Once canonoid transformations are considered, these systems can be classically described by means of Lagrangians or Hamiltonians other than the conventional ones. In this context, a basic role is played by the dynamical invariants generated through the Poisson brackets of the new independent variables in phase space. Here we obtain the explicit form of special canonoid transformations of the polynomial type for systems which can be classically described by an equation of the parametric oscillator type and discuss some algebraic properties shown by the associated dynamical invariants
Trans-Planckian effects in nonlinear-dispersion cosmologies
Full text linkWe apply a theoretical frame developed for the study of time-dependent oscillators to investigate trans-Planckian modifications induced to the standard inflationary cosmological models. Results concerning massless scalar fields subjected either the generalized Corley–Jacobson or the Unruh nonlinear dispersion relations are obtained and discussed
Generalized time-dependent oscillators:results from a group-theoretical approach and their application to cosmology
Full text linkSome results following from the analysis of generalized time-dependent oscillators in the framework of the Lie group theory are reviewed. Their role in treating aspects concerning the loss of coherence in cosmological models is discussed
Antonio Pérez (1599-1649) sobre la identidad intencional: un revisionismo del pensamiento de Pedro Auréolo
Full text linkEste artículo estudia la revisión que hace Antonio Pérez de la identidad intencional de Pedro Auréolo entre el ser aparente de una cosa como conocida y su ser real extramental. La teoría de la cognición de Pérez es claramente deudora de la teoría de la intencionalidad de Auréolo. Al igual que este, Pérez se apoya en el instrumento lógico de la connotación y en la identidad entre la especie inteligible y el acto de conocimiento. Pérez está de acuerdo con la teoría de Auréolo, afirmando una identidad de indistinción entre el ser aparente de la cosa como conocida y el ser real de la cosa extramental. Sin embargo, Pérez parece no estar plenamente satisfecho con la teoría de la cognición de Auréolo, e introduce algunos cambios relevantes. En primer lugar, emplea la doctrina suareziana de que todo acto intencional, aunque apunta directamente a un objeto, reflexiona virtual o indirectamente sobre sí mismo. Como consecuencia, apoya una identidad entre el lado formal –es decir, el acto de cognición– y el lado objetivo –es decir, la cosa reconocida–. En segundo lugar, ofrece una definición de la identidad de indistinción que difiere de la de Auréolo. Al hacerlo, Pérez equipara el ser aparente con una forma universal, es decir, el acto de cognición como tal, caracterizando todo acto particular de cognición como propio de todo ser inteligente. Esta forma indeterminada, entonces, puede ser determinada por todo objeto posible
Some Exact Solutions of the Two-Dimensional Navier-Stokes Equations
No full textINT.JOURNAL OF ENGINEERING SCIENC
Antonio Pérez (1599-1649) on Intentional Identity: A Revisionism of Peter Auriol’s Thought
No full textThis article is aimed to study Antonio Perez’s criticism against Peter Auriol’s theory of intentional identity. Pérez’s theory of cognition is clearly in debt with Auriol’s theory of intentionality. The Spanish Jesuit often uses the same linguistic expressions of Auriol (such as apparent being) and agrees with him about the intentional identity between the cogniser –conciding in act with the act of cognition–, and the cognised object, which is the same thing existing outside the intellect. Both Pérez and Auriol ground their theory of intentional identity on Aristotle’s De anima, but the Spanish Jesuit highlights an inconsistency in Auriol’s doctrine which contradicts what succinctly stated by Aristotle about the identity between the cogniser and the cognised during the act of cognition. By reviewing in-depth Auriol’s theory of intentional identity, conceived as a kind of identity of indistinction, Pérez points out an inconsistency between Auriol’s description of the act of cognition and his conception of the identity of indistinction. Furthermore, Pérez seems to consider insufficient Auriol’s identity of indistinction used to describe the intentional identity characterising the act of cognition. Consequently, he offers a new definition of the identity of indistinction in order to present the apparent being as an undetermined reality which can be determined by any intelligible content. This Perezian review of Auriol’s theory of the apparent being, on the one hand, can be considered as a case of the early modern scholastic revisionism applied to a medieval thinker and, on the other hand, finds a wider application in Pérez’s metaphysics and philosophical anthropology
Novel approach to the study of quantum effects in the early Universe
Full text linkWe develop a theoretical frame for the study of quantum gravitational waves. All the significant physical quantities can be formulated using Bogolubov transformations and the quadratic Hamiltonian operator corresponding to the classical version of a damped parametrically excited oscillator where the varying mass is replaced by the square cosmological scale factor. The destruction of quantum coherence due to the gravitational evolution in de Sitter scenarios is discussed
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