3,749 research outputs found
Fluctuations of the inverse participation ratio at the Anderson transition
Statistics of the inverse participation ratio (IPR) at the critical point of
the localization transition is studied numerically for the power-law random
banded matrix model. It is shown that the IPR distribution function is
scale-invariant, with a power-law asymptotic ``tail''. This scale invariance
implies that the fractal dimensions are non-fluctuating quantities,
contrary to a recent claim in the literature. A recently proposed relation
between and the spectral compressibility is violated in the regime
of strong multifractality, with in the limit .Comment: 4 pages, 3 eps figure
Zero-bias molecular electronics: Exchange-correlation corrections to Landauer's formula
Standard first principles calculations of transport through single molecules
miss exchange-correlation corrections to the Landauer formula. From Kubo
response theory, both the Landauer formula and these corrections in the limit
of zero bias are derived and calculations are presented.Comment: 4 pages, 3 figures, final version to appear in Phys. Rev. B, Rapid
Communication
Wave function statistics at the symplectic 2D Anderson transition: bulk properties
The wavefunction statistics at the Anderson transition in a 2d disordered
electron gas with spin-orbit coupling is studied numerically. In addition to
highly accurate exponents (), we report three qualitative results: (i) the anomalous dimensions are
invariant under which is in agreement with a recent analytical
prediction and supports the universality hypothesis. (ii) The multifractal
spectrum is not parabolic and therefore differs from behavior suspected, e.g.,
for (integer) quantum Hall transitions in a fundamental way. (iii) The critical
fixed point satisfies conformal invariance.Comment: 4 pages, 3 figure
Universality of the edge tunneling exponent of fractional quantum Hall liquids
Recent calculations of the edge tunneling exponents in quantum Hall states
appear to contradict their topological nature. We revisit this issue and find
no fundamental discrepancies. In a microscopic model of fractional quantum Hall
liquids with electron-electron interaction and confinement, we calculate the
edge Green's function via exact diagonalization. Our results for
and 2/3 suggest that in the presence of Coulomb interaction, the sharpness of
the edge and the strength of the edge confining potential, which can lead to
edge reconstruction, are the parameters that are relevant to the universality
of the electron tunneling I-V exponent.Comment: 5 pages, 3 figure
The IDEAL (Integrated Design and Engineering Analysis Languages) modeling methodology: Capabilities and Applications
The IDEAL (Integrated Design and Engineering Analysis Languages) modeling methodology has been formulated and applied over a five-year period. It has proven to be a unique, integrated approach utilizing a top-down, structured technique to define and document the system of interest; a knowledge engineering technique to collect and organize system descriptive information; a rapid prototyping technique to perform preliminary system performance analysis; and a sophisticated simulation technique to perform in-depth system performance analysis
- …