5,152 research outputs found
The time-history of a satellite around an oblate planet
Time history of satellite around oblate plane
Satellite motion for all inclinations around an oblate planet
Satellite motion for all inclinations around oblate plane
Phase separation in the particle-hole asymmetric Hubbard model
The paramagnetic phase diagram of the Hubbard model with nearest-neighbor
(NN) and next-nearest-neighbor (NNN) hopping on the Bethe lattice is computed
at half-filling and in the weakly doped regime using the self-energy functional
approach for dynamical mean-field theory. NNN hopping breaks the particle-hole
symmetry and leads to a strong asymmetry of the electron-doped and hole-doped
regimes. Phase separation occurs at and near half-filling, and the critical
temperature of the Mott transition is strongly suppressed.Comment: 8 pages, 8 figure
Shrub and tree growth in southeast Tibet: new information for dendroclimatology
Abstract HKT-ISTP 2013
B
Relaxation dynamics of the Kondo lattice model
We study the relaxation properties of the Kondo lattice model using the
nonequilibrium dynamical mean field formalism in combination with the
non-crossing approximation. The system is driven out of equilibrium either by a
magnetic field pulse which perturbs the local singlets, or by a sudden quench
of the Kondo coupling. For relaxation processes close to thermal equilibrium
(after a weak perturbation), the relaxation time increases substantially as one
crosses from the local moment regime into the heavy Fermi liquid. A strong
perturbation, which injects a large amount of energy, can rapidly transform the
heavy Fermi liquid into a local moment state. Upon cooling, the heavy Fermi
liquid reappears in a two-stage relaxation, where the first step opens the
Kondo gap and the second step corresponds to a slow approach of the equilibrium
state via a nonthermal pathway
Design approaches in technology enhanced learning
Design is a critical to the successful development of any interactive learning environment (ILE). Moreover, in technology enhanced learning (TEL), the design process requires input from many diverse areas of expertise. As such, anyone undertaking tool development is required to directly address the design challenge from multiple perspectives. We provide a motivation and rationale for design approaches for learning technologies that draws upon Simon's seminal proposition of Design Science (Simon, 1969). We then review the application of Design Experiments (Brown, 1992) and Design Patterns (Alexander et al., 1977) and argue that a patterns approach has the potential to address many of the critical challenges faced by learning technologists
Internal Anisotropy of Collision Cascades
We investigate the internal anisotropy of collision cascades arising from the
branching structure. We show that the global fractal dimension cannot give an
adequate description of the geometrical structure of cascades because it is
insensitive to the internal anisotropy. In order to give a more elaborate
description we introduce an angular correlation function, which takes into
account the direction of the local growth of the branches of the cascades. It
is demonstrated that the angular correlation function gives a quantitative
description of the directionality and the interrelation of branches. The power
law decay of the angular correlation is evidenced and characterized by an
exponent and an angular correlation length different from the radius of
gyration. It is demonstrated that the overlapping of subcascades has a strong
effect on the angular correlation.Comment: RevteX, 8 pages, 6 .eps figures include
Anomalous superconducting state gap size versus Tc behavior in underdoped Bi_2Sr_2Ca_1-xDy_xCu_2O_8+d
We report angle-resolved photoemission spectroscopy measurements of the
excitation gap in underdoped superconducting thin films of
Bi_2Sr_2Ca_{1-x}Dy_xCu_2O_{8+d}. As Tc is reduced by a factor of 2 by
underdoping, the superconducting state gap \Delta does not fall proportionally,
but instead stays constant or increases slightly, in violation of the BCS
mean-field theory result. The different doping dependences of \Delta and kT_c
indicate that they represent different energy scales. The measurements also
show that \Delta is highly anisotropic and consistent with a d_{x^2-y^2} order
parameter, as in previous studies of samples with higher dopings. However, in
these underdoped samples, the anisotropic gap persists well above T_c. The
existence of a normal state gap is related to the failure of \Delta to scale
with T_c in theoretical models that predict pairing without phase coherence
above T_c.Comment: 10 pages, 4 postscript figures, revtex forma
Systematic Control of Carrier Doping without Disorder at Interface of Oxide Heterostructures
We propose a method to systematically control carrier densities at the
interface of transition-metal oxide heterostructures without introducing
disorders. By inserting non-polar layers sandwiched by polar layers, continuous
carrier doping into the interface can be realized. This method enables us to
control the total carrier densities per unit cell systematically up to high
values of the order unity.Comment: 8 pages, 9 figure
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