145,371 research outputs found
Effects of disorder on conductance through small interacting systems
We study the effects of disorders on the transport through small interacting
systems based on a two-dimensional Hubbard cluster of finite size connected to
two noninteracting leads. This system can be regarded as a model for the
superlattice of quantum dots or atomic network of the nanometer size.
We calculate the conductance at T=0 using the order self-energy in an
electron-hole symmetric case. The results show that the conductance is ensitive
to the randomness when the resonance states are situated near the Fermi energy.Comment: 2 pages, 3 figures, to be published in Physica E, proceedings Low
Temperature Physics 23 (Hirosima, Japan
Transport through a single Anderson impurity coupled to one normal and two superconducting leads
We study the interplay between the Kondo and Andreev-Josephson effects in a
quantum dot coupled to one normal and two superconducting (SC) leads. In the
large gap limit, the low-energy states of this system can be described exactly
by a local Fermi liquid for the interacting Bogoliubov particles. The phase
shift and the renormalized parameters for the Bogoliubov particles vary
depending on the Josephson phase between the two SC leads. We explore the
precise features of a crossover that occurs between the Kondo singlet and local
Cooper-pairing states as the Josephson phase varies, using the numerical
renormalization group approach.Comment: 4 pages, 4 figures, contribution to SCES 201
Homogeneous SPC/E water nucleation in large molecular dynamics simulations
We perform direct large molecular dynamics simulations of homogeneous SPC/E
water nucleation, using up to molecules. Our large system
sizes allow us to measure extremely low and accurate nucleation rates, down to
, helping close the gap between
experimentally measured rates .
We are also able to precisely measure size distributions, sticking
efficiencies, cluster temperatures, and cluster internal densities. We
introduce a new functional form to implement the Yasuoka-Matsumoto nucleation
rate measurement technique (threshold method). Comparison to nucleation models
shows that classical nucleation theory over-estimates nucleation rates by a few
orders of magnitude. The semi-phenomenological nucleation model does better,
under-predicting rates by at worst, a factor of 24. Unlike what has been
observed in Lennard-Jones simulations, post-critical clusters have temperatures
consistent with the run average temperature. Also, we observe that
post-critical clusters have densities very slightly higher, , than
bulk liquid. We re-calibrate a Hale-type vs. scaling relation using
both experimental and simulation data, finding remarkable consistency in over
orders of magnitude in the nucleation rate range, and K in the
temperature range.Comment: Accepted for publication in the Journal of Chemical Physic
Abundance theorem for semi log canonical surfaces in positive characteristic
We prove the abundance theorem for semi log canonical surfaces in positive
characteristic.Comment: 33 pages. v2: I added Section 3, changed the definition of slc
surfaces, and adopted the one of Kollar. v3: minor change
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