694 research outputs found

    The Exact Potential Driving the Electron Dynamics in Enhanced Ionization

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    It was recently shown that the exact factorization of the electron-nuclear wavefunction allows the construction of a Schr\"odinger equation for the electronic system, in which the potential contains exactly the effect of coupling to the nuclear degrees of freedom and any external fields. Here we study the exact potential acting on the electron in charge-resonance enhanced ionization in a model one-dimensional H2+_2^+ molecule. We show there can be significant differences between the exact potential and that used in the traditional quasistatic analyses, arising from non-adiabatic coupling to the nuclear system, and that these are crucial to include for accurate simulations of time-resolved ionization dynamics and predictions of the ionization yield

    Mixed quantum-classical dynamics from the exact decomposition of electron-nuclear motion

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    We present a novel mixed quantum-classical approach to the coupled electron-nuclear dynamics based on the exact factorization of the electron-nuclear wave function, recently proposed in [A. Abedi, N. T. Maitra, and E. K. U. Gross, Phys. Rev. Lett. 105, 123002 (2010)]. In this framework, classical nuclear dynamics is derived as the lowest order approximation of the time dependent Schr\"odinger equation that describes the evolution of the nuclei. The effect of the time dependent scalar and vector potentials, representing the exact electronic back-reaction on the nuclear subsystem, is consistently derived within the classical approximation. We examine with an example the performance of the proposed mixed quantum-classical scheme in comparison with exact calculations

    Explaining and evaluating Alasdair MacIntyre's notion of tradition-constituted rationalities and justices

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    This thesis is a study on the notion of practical rationality. Its main objective is to explore whether there is a shared way of reasoning in practical and moral issues between different cultures and traditions. For this purpose, I chose MacIntyre's notion of tradition-constituted and tradition-constitutive rationality and justice (constitution thesis) as the key topic of the thesis, which holds there is no rationality and justice independent of a tradition. Rationality here is mainly practical rationality a most important outcome of which is the idea of justice. We can understand MacIntyre's constitution thesis in contrast to Cartesian epistemology and Kant's moral philosophy as they are understood by him. The constitution thesis runs counter to Cartesian epistemology by its anti-epistemological tendencies; that is to say, we do not and cannot start our substantial intellectual enquiries based on some indubitable ideas whose evidence can be shown to any rational human being. The constitution thesis runs also counter to Kantian moral philosophy by its opposition to providing a universalistic rule-based account of morality. The constitution thesis in this sense is related to virtue-ethics which emphasizes the importance of moral education and following moral masters for knowing moral duties. I will argue that we can have an account of morality that does not depend on the notion of the final good; rather, it assumes basic facts about human beings, which include their basic and intellectual needs the failure to satisfy which damages their normal and desirable functioning. The mark of real needs is that their satisfaction sustains and improves our normal and desirable functioning, and this point lets us distinguish real needs from our acquired desires and expectations. This would be against MacIntyre's claim that the justification of morality requires the notion of the human good

    Aquinas’ Theory of Knowledge and the Representative Theory of Perception

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    The representative theory of perception is one of the realist theories of perception which maintains we do not have direct access to the objects of perception; our ideas represent some objective objects in the world. In this paper, I will address the question about the representative nature of mental ideas from a Thomistic perspective. I will explore if some Thomists are entitled to claim that Aquinas’ theory of knowledge based on his metaphysics can provide a basis for resolving this issue. I will argue that this question is wrong-headed and it should be replaced with the following question: If we assume the existence of a real world and that we are not under the influence of hallucination, how we can know that our ideas truly represent the world?La teoria rappresentativa è una delle teorie “realiste” della percezione, le quali affermano che non è possibile avere un accesso diretto agli oggetti di percezione, per cui le nostre idee rappresentano solo gli oggetti nel mondo. In questo contributo, mi propongo di avvicinare la questione della natura rappresentativa delle idee mentali da una prospettiva tomista, tenendo anche in conto che per alcuni seguaci dell’Aquinate la teoria della conoscenza da lui formulata poteva effettivamente offrire una soluzione al problema. A mio avviso, la questione deve essere così riformulata: se si assume l’esistenza di un mondo reale, e nel contempo si è certi di non essere in uno stato di allucinazione, come è possibile affermare che le idee veramente rappresentano il mondo

    Alasdair MacIntyre’s Fallibilistic Interpretation of Aquinas’ Theory of Truth

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    Questo saggio cerca di fare luce sulla possibilità di un’interpretazione fallibilistica della teoria della verità di d’Aquino, attribuitagli da Alasdair MacIntyre. Prima facie, sembra strano leggere nella teoria della verità di d’Aquino un tipo di fallibilismo che si avvicina al pensiero di Popper, specialmente prendendo in considerazione la visione teologica e ottimistica di d’Aquino circa la capacità dell’intelletto di giungere alla verità. In questo saggio, argomenterò a partire da due prospettive, vale a dire i meccanismi dell’intelletto e la spiegazione di d’Aquino dei principi primi, a favore della possibilità di una versione condizionata di fallibilismo, la quale mantiene le sue differenze dalla versione popperiana.This paper seeks to shed some light on the possibility of a fallibilistic interpretation of Aquinas’ theory of truth, as attributed to him by Alasdair MacIntyre. Prima facia, it seems strange to read into Aquinas’ theory of truth a kind of fallibilism which approaches Poppers’ thought, especially taking into account the theological and optimistic view of Aquinas concerning the capacity of the intellect to arrive at truth. In this paper, I will argue from two perspectives, that is, the mechanisms of the intellect and Aquinas’ account of first principles for the possibility of a qualified version of fallibilism, which retains its differences from the Popperian version
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