95,463 research outputs found
Extending the Energy Framework for Network Simulator 3 (ns-3)
The problem of designing and simulating optimal transmission protocols for
energy harvesting wireless networks has recently received considerable
attention, thus requiring for an accurate modeling of the energy harvesting
process and a consequent redesign of the simulation framework to include it.
While the current ns-3 energy framework allows the definition of new energy
sources that incorporate the contribution of an energy harvester, the
integration of an energy harvester component into an existing energy source is
not straightforward using the existing energy framework. In this poster, we
propose an extension of the energy framework currently released with ns-3 in
order to explicitly introduce the concept of an energy harvester. Starting from
the definition of the general interface, we then provide the implementation of
two simple models for the energy harvester. In addition, we extend the set of
implementations of the current energy framework to include a model for a
supercapacitor energy source and a device energy model for the energy
consumption of a sensor. Finally, we introduce the concept of an energy
predictor, that gathers information from the energy source and harvester and
use this information to predict the amount of energy that will be available in
the future, and we provide an example implementation. As a result of these
efforts, we believe that our contributions to the ns-3 energy framework will
provide a useful tool to enhance the quality of simulations of energy-aware
wireless networks.Comment: 2 pages, 4 figures. Poster presented at WNS3 2014, Atlanta, G
Non-Markovian quantum state diffusion for an open quantum system in fermionic environments
Non-Markovian quantum state diffusion (NMQSD) provides a powerful approach to
the dynamics of an open quantum system in bosonic environments. Here we develop
an NMQSD method to study the open quantum system in fermionic environments.
This problem involves anticommutative noise functions (i.e., Grassmann
variables) that are intrinsically different from the noise functions of bosonic
baths. We obtain the NMQSD equation for quantum states of the system and the
non-Markovian master equation. Moreover, we apply this NMQSD method to single
and double quantum-dot systems.Comment: 9 pages, 1 figur
Solutions to the Jaynes-Cummings model without the rotating-wave approximation
By using extended bosonic coherent states, the solution to the
Jaynes-Cummings model without the rotating-wave approximation can be mapped to
that of a polynomial equation with a single variable. The solutions to this
polynomial equation can give all eigenvalues and eigenfunctions of this model
with all values of the coupling strength and the detuning exactly, which can be
readily applied to recent circuit quantum electrodynamic systems operating in
the ultra-strong coupling regime.Comment: 6 pages,3 figure
Dressed Feshbach molecules in the BEC-BCS crossover
We present the RPA theory of the BEC-BCS crossover in an atomic Fermi gas
near a Feshbach resonance that includes the relevant two-body atomic physics
exactly. This allows us to determine the probability for the dressed
molecules in the Bose-Einstein condensate to be in the closed channel of the
Feshbach resonance and to compare with the recent experiments of Partridge {\it
et al.} [cond-mat/0505353] with Li. We determine for this extremely broad
resonance also the condensate density of the dressed molecules throughout the
BEC-BCS crossover.Comment: 4 pages, 3 figure
Nuclear modification factor in intermediate-energy heavy-ion collisions
The transverse momentum dependent nuclear modification factors (NMF), namely
, is investigated for protons produced in Au + Au at 1 GeV within
the framework of the isospin-dependent quantum molecular dynamics (IQMD) model.
It is found that the radial collective motion during the expansion stage
affects the NMF at low transverse momentum a lot. By fitting the transverse
mass spectra of protons with the distribution function from the Blast-Wave
model, the magnitude of radial flow can be extracted. After removing the
contribution from radial flow, the can be regarded as a thermal one
and is found to keep unitary at transverse momentum lower than 0.6 GeV/c and
enhance at higher transverse momentum, which can be attributed to Cronin
effect.Comment: 8 pages, 5 figures; aceepted by Physics Letters
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