44,403 research outputs found
Mean-Field and Non-Mean-Field Behaviors in Scale-free Networks with Random Boolean Dynamics
We study two types of simplified Boolean dynamics over scale-free networks,
both with synchronous update. Assigning only Boolean functions AND and XOR to
the nodes with probability and , respectively, we are able to analyze
the density of 1's and the Hamming distance on the network by numerical
simulations and by a mean-field approximation (annealed approximation). We show
that the behavior is quite different if the node always enters in the dynamic
as its own input (self-regulation) or not. The same conclusion holds for the
Kauffman KN model. Moreover, the simulation results and the mean-field ones (i)
agree well when there is no self-regulation, and (ii) disagree for small
when self-regulation is present in the model.Comment: 12 pages, 7 figure
Effective action for a quantum scalar field in warped spaces
We investigate the one-loop corrections at zero, as well as finite
temperature, of a scalar field taking place in a braneworld motived warped
background. After to reach a well defined problem, we calculate the effective
action with the corresponding quantum corrections to each case.Comment: 10 pages, to appear in The European Physical Journal
Oxygen clamps in gold nanowires
We investigate how the insertion of an oxygen atom in an atomically thin gold
nanowire can affect its rupture. We find, using ab initio total energy density
functional theory calculations, that O atoms when inserted in gold nanowires
form not only stable but also very strong bonds, in such a way that they can
extract atoms from a stable tip, serving in this way as a clamp that could be
used to pull a string of gold atoms.Comment: 4 pages; 4 figure
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