85,766 research outputs found
Quantumness beyond quantum mechanics
Bohmian mechanics allows us to understand quantum systems in the light of
other quantum traits than the well-known ones (coherence, diffraction,
interference, tunneling, discreteness, entanglement, etc.). Here the discussion
focusses precisely on two of these interesting aspects, which arise when
quantum mechanics is though within this theoretical framework: the non-crossing
property, which allows for distinguishability without erasing interference
patterns, and the possibility to define quantum probability tubes, along which
the probability remains constant all the way. Furthermore, taking into account
this hydrodynamic-like description as a link, it is also shown how this
knowledge (concepts and ideas) can be straightforwardly transferred to other
fields of physics (for example, the transmission of light along waveguides).Comment: 11 pages, 4 figures; based on a talk at the Conference "Emergent
Quantum Mechanics" / 5th Heinz von Foerster Congress (Vienna, Nov 11-13,
2011
Investigating transition state resonances in the time domain by means of Bohmian mechanics: The F+HD reaction
In this work, we investigate the existence of transition state resonances on
atom-diatom reactive collisions from a time-dependent perspective, stressing
the role of quantum trajectories as a tool to analyze this phenomenon. As it is
shown, when one focusses on the quantum probability current density, new
dynamical information about the reactive process can be extracted. In order to
detect the effects of the different rotational populations and their
dynamics/coherences, we have considered a reduced two-dimensional dynamics
obtained from the evolution of a full three-dimensional quantum time-dependent
wave packet associated with a particular angle. This reduction procedure
provides us with information about the entanglement between the radial degrees
of freedom (r,R) and the angular one (\gamma), which can be considered as
describing an environment. The combined approach here proposed has been applied
to study the F+HD reaction, for which the FH+D product channel exhibits a
resonance-mediated dynamics.Comment: 12 pages, 9 figure
Intelligence, Control and the Artificial Mind
Artificial intelligence and cognitive science must look at the world of industrial-process control to find the technological reifications of the concept of mind
Signatures of Non-Standard Electroweak Symmetry Breaking
This is the write-up of a talk given at the EW session in Moriond (March
2012). I summarize some non-standard electroweak scenarios, and how they
predict the existence of new spin-two resonances. Spin-two resonances, whether
coming from the compactification of extra-dimensions or from a new sector of
strong interactions, exhibit the same interactions with the Standard Model.
This is a consequence of Lorentz and CP invariance, which we assume would be
preserved by the new strong sector. Although this would seem to support the
holographic duality between strongly interacting theories in four-dimensions
and extra-dimensional theories, I show that there is a way to distinguish
between the two sides of the "duality", which constitutes an explicit example
of its breakdown
Income Tax Revenue Elasticities in Spain: Individual and Aggregate Measures
This paper derives analytical expressions for the revenue elasticity of the Spanish personal income tax system, as applied to tax units and in aggregate. This is complicated by the schedular nature of the system, and the role of central and regional governments, along with the existence of a range of tax credits and eligible expenditures and deductions. Empirical estimates are obtained using a cross-sectional dataset which enables a number of important ancillary elasticities (relating to allowances and tax credits, and different income sources) to be estimated. It was found that there is considerable variation among tax units in the revenue elasticity, with highly (positively)skewed distributions. The nature of the distributions varies among regions of Spain, and the aggregate elasticities for each region were found to display some variation associated with income distribution differences. The national aggregate is found to be around 1.3.
Modelling Personal Income Taxation in Spain:Revenue Elasticities and Regional Comparisons
This paper derives analytical expressions for the revenue elasticity of the Spanish personal income tax system, as applied to tax units and in aggregate. This is complicated by the schedular nature of the system, and the role of central and regional governments, along with the existence of a range of tax credits and eligible expenditures and deductions. Empirical estimates are obtained using a cros -sectional dataset which enables a number of important ancillary elasticities (relating to allowances and tax credits, and different income sources) to be estimated. It was found that there is considerable variation among tax units in the revenue elasticity, with highly (positively) skewed distributions. The nature of the distributions varies among regions of Spain, and the aggregate elasticities for each region were found to display some variation associated with income distribution differences. The national aggregate is found to be around 1.3. The paper also derives aggregate tax revenue as a function of characteristics of the distribution of taxable income in each region. This allows the sources of revenue differences among regions to be identified.
Modelling Aggregate Personal Income Tax Revenue in Multi-Schedular and Multi-Regional Structures
This paper derives analytical expressions for aggregate personal income tax revenue obtained from a multi-schedular and multi-regional personal income tax system, with revenue divided among central and regional governments. Aggregate income tax revenue is expressed as a function of characteristics of the distribution of taxable income, making it possible to identify the sources of revenue differences among regions. The approach is applied to the tax structure in Spain, and the effects of income distribution differences among the Spanish regions is examined.
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