2,034 research outputs found
Crackling Noise in Fractional Percolation -- Randomly distributed discontinuous jumps in explosive percolation
Crackling noise is a common feature in many systems that are pushed slowly,
the most familiar instance of which is the sound made by a sheet of paper when
crumpled. In percolation and regular aggregation clusters of any size merge
until a giant component dominates the entire system. Here we establish
`fractional percolation' where the coalescence of clusters that substantially
differ in size are systematically suppressed. We identify and study percolation
models that exhibit multiple jumps in the order parameter where the position
and magnitude of the jumps are randomly distributed - characteristic of
crackling noise. This enables us to express crackling noise as a result of the
simple concept of fractional percolation. In particular, the framework allows
us to link percolation with phenomena exhibiting non-self-averaging and power
law fluctuations such as Barkhausen noise in ferromagnets.Comment: non-final version, for final see Nature Communications homepag
Data Requirements for Oceanic Processes in the Open Ocean, Coastal Zone, and Cryosphere
The type of information system that is needed to meet the requirements of ocean, coastal, and polar region users was examined. The requisite qualities of the system are: (1) availability, (2) accessibility, (3) responsiveness, (4) utility, (5) continuity, and (6) NASA participation. The system would not displace existing capabilities, but would have to integrate and expand the capabilities of existing systems and resolve the deficiencies that currently exist in producer-to-user information delivery options
Spin Wave Response in the Dilute Quasi-one Dimensional Ising-like Antiferromagnet CsCo_{0.83}Mg_{0.17}Br_3
Inelastic neutron scattering profiles of spin waves in the dilute
quasi-one-dimensional Ising-like antiferromagnet CsCo_{0.83}Mg_{0.17}Br_3 have
been investigated. Calculations of S^{xx}(Q,omega), based on an effective spin
Hamiltonian, accurately describe the experimental spin wave spectrum of the 2J
mode. The Q dependence of the energy of this spin wave mode follows the
analytical prediction
omega_{xx}(Q)=(2J)(1-5epsilon^{2}cos^{2}Qa+2epsilon^{2})^{1/2}, calculated by
Ishimura and Shiba using perturbation theory.Comment: 13 pages, 4 figure
Genuine Non-Self-Averaging and Ultra-Slow Convergence in Gelation
In irreversible aggregation processes droplets or polymers of microscopic
size successively coalesce until a large cluster of macroscopic scale forms.
This gelation transition is widely believed to be self-averaging, meaning that
the order parameter (the relative size of the largest connected cluster)
attains well-defined values upon ensemble averaging with no sample-to-sample
fluctuations in the thermodynamic limit. Here, we report on anomalous gelation
transition types. Depending on the growth rate of the largest clusters, the
gelation transition can show very diverse patterns as a function of the control
parameter, which includes multiple stochastic discontinuous transitions,
genuine non-self-averaging and ultra-slow convergence of the transition point.
Our framework may be helpful in understanding and controlling gelation.Comment: 8 pages, 10 figure
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