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Tidal dynamics in cosmological spacetimes
(Institute of Physics, 2007)
We study the relative motion of nearby free test particles in cosmological spacetimes, such as the FLRW and LTB models. In particular, the influence of spatial inhomogeneities on local tidal accelerations is investigated ...
Nonlocal Dirac equation for accelerated observers
(American Physical Society, 2007)
The nonlocal theory of accelerated systems is extended to the propagation of Dirac particles. The implications of nonlocality for the phenomenon of spin-rotation coupling are discussed. The Lorentz-invariant nonlocal Dirac ...
Decaying dark energy in higher-dimensional gravity
(EDP Sciences, 2007)
Aims. We use data from observational cosmology to put constraints on higher-dimensional extensions of general relativity in which the effective four-dimensional dark-energy density (or cosmological “constant”) decays with ...
An Embedding for General Relativity and its Implications for New Physics
(arXiv, 2007)
We show that any solution of the 4D Einstein equations of general relativity in vacuum with a cosmological constant may be embedded in a solution of the 5D Ricci-flat equations with an effective 4D cosmological "constant" ...
Nonlocal Electrodynamics of Accelerated Systems
(arXiv, 2007)
Acceleration-induced nonlocality is discussed and a simple field theory of nonlocal electrodynamics is developed. The theory involves a pair of real parameters that are to be determined from observation. The implications ...
Generation of fast propagating combustion and shock waves with copper oxide/aluminum nanothermite composites
(American Institute of Physics, 2007)
Nanothermite composites containing metallic fuel and inorganic oxidizer are gaining importance due to their outstanding combustion characteristics. In this paper, the combustion behaviors of copper oxide/aluminum nanothermites ...
Eukaryotic membrane tethers revisited using magnetic tweezers
(Institute of Physics, 2007)
Membrane nanotubes, under physiological conditions, typically form en masse. We employed magnetic tweezers (MTW) to extract tethers from human brain tumor cells and compared their biophysical properties with tethers extracted ...
Crystallization of amorphous silicon by self-propagation of nanoengineered thermites
(American Institute of Physics, 2007)
Crystallization of amorphous silicon (a-Si) thin film occurred by the self-propagation of copper oxide/aluminum thermite nanocomposites. Amorphous Si films were prepared on glass at a temperature of 250 °C by plasma ...
Nanoclustering of vacancies in thin metal films revealed by x-ray diffuse scattering
(American Institute of Physics, 2007)
The authors report the incorporation of unexpectedly large vacancy clusters into homoepitaxial Ag(001) films. These results, which are for a simple noble metal system, have important implications for understanding the ...
Electronic viscosity in a quantum well: A test for the local-density approximation
(American Physical Society, 2007)
In the local-density approximation (LDA) for electronic time-dependent current-density-functional theory, many-body effects are described in terms of the viscoelastic constants of the homogeneous three-dimensional electron ...
Theory of the Pseudospin Resonance in Semiconductor Bilayers
(American Physical Society, 2007)
The pseudospin degree of freedom in a semiconductor bilayer gives rise to a collective mode analogous to the ferromagnetic-resonance mode of a ferromagnet. We present a many-body theory of the dependence of the energy and ...
Introductory Physics: Writing scheme teaches science to non-scientists
(Institute of Physics, 2007)
Writing-intensive activities can be made use of to implement a 'narrow-but-deep' approach in an undergraduate introductory physics course for non-science majors. In this approach, a carefully selected number of topics are ...
Complex pore spaces create record-breaking methane storage system for natural-gas vehicles
(American Institute of Physics, 2007)
It has been proposed that nearly space-filling networks of nanopores in biocarbon may provide a “sponge” for lowpressure,
high-capacity storage of methane CH4 for advanced transportation.1 Such pores, a few molecular ...
Intersubband spin-orbit coupling and spin splitting in symmetric quantum wells
(arXiv, 2007)
In semiconductors with inversion asymmetry, spin-orbit coupling gives rise to the well-known Dresselhaus and Rashba effects. If one considers quantum wells with two or more conduction subbands, an additional, intersubband-induced ...
Spin Drag and Spin-Charge Separation in Cold Fermi Gases
(American Physical Society, 2007)
Low-energy spin and charge excitations of one-dimensional interacting fermions are completely decoupled and propagate with different velocities. These modes, however, can decay due to several possible mechanisms. In this ...
Money for Nothing? The Impact of Changes in the Pell Grant Program on Institutional Revenues and the Placement of Needy Students
(American Education Finance Association, 2007)
Using new institutional-level data, we assess the impact of changing federal aid levels on institutional-level Pell revenues. Using various policy instruments associated with Pell generosity, we quantify the sensitivity ...
Imaging 2D Optical Diffuse Reflectance in Skeletal Muscle
(The Optical Society of America, 2007-04)
We discovered a unique pattern of optical reflectance from fresh prerigor skeletal muscles, which can not be described using existing theories. A numerical fitting function was developed to quantify the equiintensity ...
Exchange and correlation effects on plasmon dispersions and Coulomb drag in low-density electron bilayers
(American Physical Society, 2007)
We investigate the effect of exchange and correlation (XC) on the plasmon spectrum and the Coulomb drag between spatially separated low-density two-dimensional electron layers. We adopt a different approach, which employs ...
Degenerate ground states and nonunique potentials: Breakdown and restoration of density functionals
(American Physical Society, 2007)
The Hohenberg-Kohn (HK) theorem is one of the most fundamental theorems of quantum mechanics, and constitutes the basis for the very successful density-functional approach to inhomogeneous interacting many-particle systems. ...
Gilbert damping and spin Coulomb drag in a magnetized electron liquid with spin-orbit interaction
(American Physical Society, 2007)
We present a microscopic calculation of the Gilbert damping constant for the magnetization of a two-dimensional spin- polarized electron liquid in the presence of intrinsic spin-orbit interaction. First, we show that the ...