13,609 research outputs found
Two-dimensional small-world networks: navigation with local information
Navigation process is studied on a variant of the Watts-Strogatz small world
network model embedded on a square lattice. With probability , each vertex
sends out a long range link, and the probability of the other end of this link
falling on a vertex at lattice distance away decays as .
Vertices on the network have knowledge of only their nearest neighbors. In a
navigation process, messages are forwarded to a designated target. For and , a scaling relation is found between the average actual
path length and , where is the average length of the additional long
range links. Given , dynamic small world effect is observed, and the
behavior of the scaling function at large enough is obtained. At and 3, this kind of scaling breaks down, and different functions of the
average actual path length are obtained. For , the average actual
path length is nearly linear with network size.Comment: Accepted for publication in Phys. Rev.
Small-World Network Effect in Competing Glauber- and Kawasaki-type Dynamics
In this article, we investigate the competing Glauber-type and Kawasaki-type
dynamics with small-world network (SWN) effect, in the framework of the
Gaussian model. The Glauber-type single-spin transition mechanism with
probability p simulates the contact of the system with a heat bath and the
Kawasaki-type dynamics with probability 1-p simulates an external energy flux.
Two different types of SWN effect are studied, one with the total number of
links increased and the other with it conserved. The competition of the
dynamics leads to an interesting self-organization process that can be
characterized by a phase diagram with two identifiable temperatures. By
studying the modification of the phase diagrams, the SWN effect on the two
dynamics is analyzed. For the Glauber-type dynamics, more important is the
altered average coordination number while the Kawasaki-type dynamics is
enhanced by the long range spin interaction and redistribution.Comment: 18 pages, 1 figure. Accepted for publication in "The European
Physical Journal B (EPJB)
Tracking ocean heat uptake during the surface warming hiatus.
Ocean heat uptake is observed to penetrate deep into the Atlantic and Southern Oceans during the recent hiatus of global warming. Here we show that the deep heat penetration in these two basins is not unique to the hiatus but is characteristic of anthropogenic warming and merely reflects the depth of the mean meridional overturning circulation in the basin. We find, however, that heat redistribution in the upper 350 m between the Pacific and Indian Oceans is closely tied to the surface warming hiatus. The Indian Ocean shows an anomalous warming below 50 m during hiatus events due to an enhanced heat transport by the Indonesian throughflow in response to the intensified trade winds in the equatorial Pacific. Thus, the Pacific and Indian Oceans are the key regions to track ocean heat uptake during the surface warming hiatus
Quantum coherence of the molecular states and their corresponding currents in nanoscale Aharonov-Bohm interferometers
By considering a nanoscale Aharonov-Bohm (AB) interferometer containing a
parrallel-coupled double dot coupled to the source and drain electrodes, we
investigate the AB phase oscillations of transport current via the bonding and
antibonding state channels. The results we obtained justify the experimental
analysis given in [Phys. Rev. Lett. \textbf{106}, 076801 (2011)] that bonding
state currents in different energy configurations are almost the same. On the
other hand, we extend the analysis to the transient transport current
components flowing through different channels, to explore the effect of the
parity of bonding and antibonding states on the AB phase dependence of the
corresponding current components in the transient regime. The relations of the
AB phase dependence between the quantum states and the associated current
components are analyzed in details, which provides useful information for the
reconstruction of quantum states through the measurement of the transport
current in such systems. With the coherent properties in the quantum dot states
as well as in the transport currents, we also provide a way to manipulate the
bonding and antibonding states by the AB magnetic flux.Comment: 10 pages, 7 figure
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