2,147,540 research outputs found
Does Geometric Coupling Generates Resonances?
Geometrical coupling in a co-dimensional one Randall-Sundrum scenario (RS) is
used to study resonances of form fields. The resonances are calculated
using the transfer matrix method. The model studied consider the standard RS
with delta-like branes, and branes generated by kinks and domain-wall as well.
The parameters are changed to control the thickness of the smooth brane. With
this a very interesting pattern is found for the resonances. The geometrical
coupling does not generate resonances for the reduced form in all cases
considered.Comment: 10 pages, 10 figure
Motion generates entanglement
We demonstrate entanglement generation between mode pairs of a quantum field
in a nonuniformly accelerated cavity in Minkowski space-time. The effect is
sensitive to the initial state, the choice of the mode pair and bosonic versus
fermionic statistics, and it can be stronger by orders of magnitude than the
entanglement degradation between a nonuniformly accelerated cavity and an
inertial cavity. Detailed results are obtained for massless scalar and spinor
fields in (1+1) dimensions. By the equivalence principle, the results provide a
model of entanglement generation by gravitational effects.Comment: 5 pages, 2 figures, Ivette Fuentes previously published as Ivette
Fuentes-Guridi and Ivette Fuentes-Schuller; v3: minor changes, updated
reference
Planar growth generates scale free networks
In this paper we introduce a model of spatial network growth in which nodes
are placed at randomly selected locations on a unit square in ,
forming new connections to old nodes subject to the constraint that edges do
not cross. The resulting network has a power law degree distribution, high
clustering and the small world property. We argue that these characteristics
are a consequence of the two defining features of the network formation
procedure; growth and planarity conservation. We demonstrate that the model can
be understood as a variant of random Apollonian growth and further propose a
one parameter family of models with the Random Apollonian Network and the
Deterministic Apollonian Network as extreme cases and our model as a midpoint
between them. We then relax the planarity constraint by allowing edge crossings
with some probability and find a smooth crossover from power law to exponential
degree distributions when this probability is increased.Comment: 27 pages, 9 figure
A Formula That Generates Hash Collisions
We present an explicit formula that produces hash collisions for the
Merkle-Damg{\aa}rd construction. The formula works for arbitrary choice of
message block and irrespective of the standardized constants used in hash
functions, although some padding schemes may cause the formula to fail. This
formula bears no obvious practical implications because at least one of any
pair of colliding messages will have length double exponential in the security
parameter. However, due to ambiguity in existing definitions of collision
resistance, this formula arguably breaks the collision resistance of some hash
functions.Comment: 10 page
Localized shear generates three-dimensional transport
Understanding the mechanisms that control three-dimensional (3D) fluid
transport is central to many processes including mixing, chemical reaction and
biological activity. Here a novel mechanism for 3D transport is uncovered where
fluid particles are kicked between streamlines near a localized shear, which
occurs in many flows and materials. This results in 3D transport similar to
Resonance Induced Dispersion (RID); however, this new mechanism is more rapid
and mutually incompatible with RID. We explore its governing impact with both
an abstract 2-action flow and a model fluid flow. We show that transitions from
one-dimensional (1D) to two-dimensional (2D) and 2D to 3D transport occur based
on the relative magnitudes of streamline jumps in two transverse directions.Comment: Copyright 2017 AIP Publishing. This article may be downloaded for
personal use only. Any other use requires prior permission of the author and
AIP Publishin
Individual heterogeneity generates explosive system network dynamics
Individual heterogeneity is a key characteristic of many real-world systems,
from organisms to humans. However its role in determining the system's
collective dynamics is typically not well understood. Here we study how
individual heterogeneity impacts the system network dynamics by comparing
linking mechanisms that favor similar or dissimilar individuals. We find that
this heterogeneity-based evolution can drive explosive network behavior and
dictates how a polarized population moves toward consensus. Our model shows
good agreement with data from both biological and social science domains. We
conclude that individual heterogeneity likely plays a key role in the
collective development of real-world networks and communities, and cannot be
ignored.Comment: 6 pages, 4 figure
When Inertia Generates Political Cycles
In this note, we propose a simple infinite horizon of elections with two candidates. We suppose that the government policy presents some degree of inertia, i.e. a new government cannot completely change the policy implemented by the incumbent. When the policy inertia is strong enough, no party can win the elections a consecutive infinite number of times.Policy inertia
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