19,734 research outputs found
Fisher Information and Kinetic-energy Functionals: A Dequantization Approach
We strengthen the connection between Information Theory and
quantum-mechanical systems using a recently developed dequantization procedure
whereby quantum fluctuations latent in the quantum momentum are suppressed. The
dequantization procedure results in a decomposition of the quantum kinetic
energy as the sum of a classical term and a purely quantum term. The purely
quantum term, which results from the quantum fluctuations, is essentially
identical to the Fisher information. The classical term is complementary to the
Fisher information and, in this sense, it plays a role analogous to that of the
Shannon entropy. We demonstrate the kinetic energy decomposition for both
stationary and nonstationary states and employ it to shed light on the nature
of kinetic-energy functionals.Comment: 13 pages, 3 figures. To appear in J. Comput. Appl. Mat
Energy and urban built form: an empirical and statistical approach
The geometrical forms of buildings have important effects on their use of energy. These relationships are explored at the scale of the entire non-domestic building stock of London. A three-dimensional digital model of the city is used to make a series of geometrical measures: building volume, exposed surface area (walls plus roof) and plan depth. These are compared with figures for the consumption of gas and electricity published by the UK Department of Energy and Climate Change (DECC). The comparisons are made at different levels of spatial aggregation, from boroughs to census districts. Strong correlations are demonstrated between exposed surface area and both gas and electricity use. The analysis also provides some evidence of a sharp increase in electricity use in districts with buildings whose depth in plan exceeds 14 m (in which air-conditioning and permanent artificial lighting are typically required). A multiple regression model is used to measure the contribution of these effects to total energy use, as compared with floor area, activities and number of employees
Designing Carbon Taxation to Protect Low-Income Households
Would it be possible to increase carbon taxes on household energy use and transport, while protecting low-income households from negative impacts
On the generalized continuity equation
A generalized continuity equation extending the ordinary continuity equation
has been found using quanternions. It is shown to be compatible with Dirac,
Schrodinger, Klein-Gordon and diffusion equations. This generalized equation is
Lorentz invariant. The transport properties of electrons are found to be
governed by Schrodinger-like equation and not by the diffusion equation.Comment: 9 Latex pages, no figure
Erratum: "Ab initio calculations on the ground and excited states of BeOH and MgOH" [J. Chem. Phys. 111, 10484 (1999)]
Journal URL: http://jcp.aip.org
Ab initio calculations on the ground and excited states of BeOH and MgOH
Journal URL: http://jcp.aip.org
Ricci flow for homogeneous compact models of the universe
Using quaternions, we give a concise derivation of the Ricci tensor for
homogeneous spaces with topology of the 3-dimensional sphere. We derive
explicit and numerical solutions for the Ricci flow PDE and discuss their
properties. In the collapse (or expansion) of these models, the interplay of
the various components of the Ricci tensor are studied. We dedicate this paper
to honor the work of Josh Goldberg.Comment: 18 pages, 2 figure
Interplay between one-dimensional confinement and crystallographic anisotropy in ballistic hole quantum wires
We study the Zeeman splitting in induced ballistic 1D quantum wires aligned
along the [233] and [011] axes of a high mobility (311)A undoped
heterostructure. Our data shows that the g-factor anisotropy for magnetic
fields applied along the high symmetry [011] direction can be explained by the
1D confinement only. However when the magnetic field is along [233] there is an
interplay between the 1D confinement and 2D crystal anisotropy. This is
highlighted for the [233] wire by an unusual non-monotonic behavior of the
g-factor as the wire is made narrower
Extensive Prefrontal Cortex Haemodynamic Changes Provoked By Intense Aerobic Exercise, Measured Via FNIRS
Probing the Sensitivity of Electron Wave Interference to Disorder-Induced Scattering in Solid-State Devices
The study of electron motion in semiconductor billiards has elucidated our
understanding of quantum interference and quantum chaos. The central assumption
is that ionized donors generate only minor perturbations to the electron
trajectories, which are determined by scattering from billiard walls. We use
magnetoconductance fluctuations as a probe of the quantum interference and show
that these fluctuations change radically when the scattering landscape is
modified by thermally-induced charge displacement between donor sites. Our
results challenge the accepted understanding of quantum interference effects in
nanostructures.Comment: 8 pages, 5 figures, Submitted to Physical Review
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