13,508 research outputs found
A Hybrid Quantum Encoding Algorithm of Vector Quantization for Image Compression
Many classical encoding algorithms of Vector Quantization (VQ) of image
compression that can obtain global optimal solution have computational
complexity O(N). A pure quantum VQ encoding algorithm with probability of
success near 100% has been proposed, that performs operations 45sqrt(N) times
approximately. In this paper, a hybrid quantum VQ encoding algorithm between
classical method and quantum algorithm is presented. The number of its
operations is less than sqrt(N) for most images, and it is more efficient than
the pure quantum algorithm.
Key Words: Vector Quantization, Grover's Algorithm, Image Compression,
Quantum AlgorithmComment: Modify on June 21. 10pages, 3 figure
Phonon Density of States and Anharmonicity of UO2
Phonon density of states (PDOS) measurements have been performed on
polycrystalline UO2 at 295 and 1200 K using time-of-flight inelastic neutron
scattering to investigate the impact of anharmonicity on the vibrational
spectra and to benchmark ab initio PDOS simulations performed on this strongly
correlated Mott-insulator. Time-of-flight PDOS measurements include anharmonic
linewidth broadening inherently and the factor of ~ 7 enhancement of the oxygen
spectrum relative to the uranium component by the neutron weighting increases
sensitivity to the oxygen-dominated optical phonon modes. The first-principles
simulations of quasi-harmonic PDOS spectra were neutron-weighted and
anharmonicity was introduced in an approximate way by convolution with
wavevector-weighted averages over our previously measured phonon linewidths for
UO2 that are provided in numerical form. Comparisons between the PDOS
measurements and the simulations show reasonable agreement overall, but they
also reveal important areas of disagreement for both high and low temperatures.
The discrepancies stem largely from an ~ 10 meV compression in the overall
bandwidth (energy range) of the oxygen-dominated optical phonons in the
simulations. A similar linewidth-convoluted comparison performed with the PDOS
spectrum of Dolling et al. obtained by shell-model fitting to their historical
phonon dispersion measurements shows excellent agreement with the
time-of-flight PDOS measurements reported here. In contrast, we show by
comparisons of spectra in linewidth-convoluted form that recent
first-principles simulations for UO2 fail to account for the PDOS spectrum
determined from the measurements of Dolling et al. These results demonstrate
PDOS measurements to be stringent tests for ab initio simulations of phonon
physics in UO2 and they indicate further the need for advances in theory to
address lattice dynamics of UO2.Comment: Text slightly modified, results unchange
Normal families and fixed points of iterates
Let F be a family of holomorphic functions and let K be a constant less than
4. Suppose that for all f in F the second iterate of f does not have fixed
points for which the modulus of the multiplier is greater than K. We show that
then F is normal. This is deduced from a result about the multipliers of
iterated polynomials.Comment: 5 page
Photoluminescence and spectral switching of single CdSe/ZnS colloidal nanocrystals in poly(methyl methacrylate)
Emission from single CdSe nanocrystals in PMMA was investigated. A fraction
of the nanocrystals exhibiting switching between two energy states, which have
similar total intensities, but distinctly different spectra were observed. We
found that the spectral shift characteristic frequency increases with the pump
power. By using the dynamic shift in the spectral position of emission peaks,
we were able to correlate peaks from the same nanocrystal. The measured
correlation is consistent with assignment of low energy lines to phonon
replicas.Comment: 5 pages, 4 figure
Application of new physical storage technology in fruit and vegetable industry
With the development of science and technology, consumers not only require food to be safe, but also require them to keep the original natural flavor and nutritional value as well, while the traditional chemical storage method has been increasingly unable to satisfy consumers’ demand. When compared with chemical method, physical technology has more obvious advantage. This article introduces some commonly-used chemical methods and some modern methods.Key words: New physical storage technology, plasma storage technology, electrolyzed reduction water technology, super ice-temperature technolog
Nanodot-Cavity Electrodynamics and Photon Entanglement
Quantum electrodynamics of excitons in a cavity is shown to be relevant to
quantum operations. We present a theory of an integrable solid-state quantum
controlled-phase gate for generating entanglement of two photons using a
coupled nanodot-microcavity-fiber structure. A conditional phase shift of
is calculated to be the consequence of the giant optical
nonlinearity keyed by the excitons in the cavities. Structural design and
active control, such as electromagnetic induced transparency and pulse shaping,
optimize the quantum efficiency of the gate operation.Comment: 4 pages 3 figure
Particle production and equilibrium properties within a new hadron transport approach for heavy-ion collisions
The microscopic description of heavy-ion reactions at low beam energies is
achieved within hadronic transport approaches. In this article a new approach
SMASH (Simulating Many Accelerated Strongly-interacting Hadrons) is introduced
and applied to study the production of non-strange particles in heavy-ion
reactions at GeV. First, the model is described including
details about the collision criterion, the initial conditions and the resonance
formation and decays. To validate the approach, equilibrium properties such as
detailed balance are presented and the results are compared to experimental
data for elementary cross sections. Finally results for pion and proton
production in C+C and Au+Au collisions is confronted with HADES and FOPI data.
Predictions for particle production in collisions are made.Comment: 30 pages, 30 figures, replaced with published version; only minor
change
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