2,082 research outputs found
Trajectory Design of Laser-Powered Multi-Drone Enabled Data Collection System for Smart Cities
This paper considers a multi-drone enabled data collection system for smart cities, where there are two kinds of drones, i.e., Low Altitude Platforms (LAPs) and a High Altitude Platform (HAP). In the proposed system, the LAPs perform data collection tasks for smart cities and the solar-powered HAP provides energy to the LAPs using wireless laser beams. We aim to minimize the total laser charging energy of the HAP, by jointly optimizing the LAPs’ trajectory and the laser charging duration for each LAP, subject to the energy capacity constraints of the LAPs. This problem is formulated as a mixed-integer and non-convex Drones Traveling Problem (DTP), which is a combinatorial optimization problem and NP-hard. We propose an efficient and novel search algorithm named DronesTraveling Algorithm (DTA) to obtain a near-optimal solution. Simulation results show that DTA can deal with the large scale DTP (i.e., more than 400 data collection points) efficiently. Moreover, the DTA only uses 5 iterations to obtain the nearoptimal solution whereas the normal Genetic Algorithm needs nearly 10000 iterations and still fails to obtain an acceptable solution
Scalable Generation and Characterization of a Four-Photon Twelve-Qubit Hyperentangled State
An experimentally feasible scheme for generating a 12-qubit hyperentangled
state via four photons, entangled in polarization, frequency and spatial mode,
is proposed. We study the nature of quantum non-locality of this hyperentangled
state by evaluating its violation degree to a Bell-type inequality, and find
that the result agrees well with quantum mechanics prediction while extremely
contradicts to the local realism constraint.Comment: 14 pages, 6 Postscript figure
Implications of chiral symmetry on -wave pionic resonances and the scalar charmed mesons
The chiral symmetry of QCD requires energy-dependent pionic strong
interactions at low energies. This constraint, however, is not fulfilled by the
usual Breit--Wigner parameterization of pionic resonances, leading to masses
larger than the real ones. We derive relations between nonleptonic three-body
decays of the -meson into a -meson and a pair of light pseudoscalar
mesons based on SU(3) chiral symmetry. Employing effective field theory
methods, we demonstrate that taking into account the final-state interactions,
the experimental data of the decays , , , and
can all be described by the nonperturbative
- scattering amplitudes previously obtained from a
combination of chiral effective field theory and lattice QCD calculations. The
results provide a strong support of the scenario that the broad scalar charmed
meson should be replaced by two states, the lower one of which
has a mass of around 2.1 GeV, much smaller than that extracted from
experimental data using a Breit--Wigner parameterization.Comment: 26 pages, 9 figuere
One-loop renormalization of the chiral Lagrangian for spinless matter fields in the SU(N) fundamental representation
We perform the leading one-loop renormalization of the chiral Lagrangian for
spinless matter fields living in the fundamental representation of SU(N). The
Lagrangian can also be applied to any theory with a spontaneous symmetry
breaking of to and spinless matter fields in
the fundamental representation. For QCD, the matter fields can be kaons or
pseudoscalar heavy mesons. Using the background field method and heat kernel
expansion techniques, the divergences of the one-loop effective generating
functional for correlation functions of single matter fields are calculated up
to . They are absorbed by counterterms not only from the
third order but also from the second order chiral Lagrangian.Comment: 13 page
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