8,842 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
Ferromagnetism in the Infinite-U Hubbard Model
We have studied the stability of the ferromagnetic state in the infinite-U
Hubbard model on a square lattice by approximate diagonalization of finite
lattices using the density matrix renormalization group technique. By studying
lattices with up to 5X20 sites, we have found the ferromagnetic state to be
stable below the hole density of 22 percent. Beyond 22 percent of hole doping,
the total spin of the ground state decreased gradually to zero with increasing
hole density.Comment: 13 pages, RevteX 3.0, seven figures appended in uuencoded form,
correcting problems with uuencoded figure
Novel water-assisting low firing MoO3 microwave dielectric ceramics
MoO3 ceramics can not be well densified via conventional solid state method and a low relative density (ρ) was obtained (˜64.5% at 680 °C) with a permittivity (εr) ˜ 7.58, a quality factor (Qf) ˜ 35,000 GHz and a temperature coefficient of resonant frequency (TCF) ˜ − 39 ppm/°C. However, cold sintering at 150 °C using 4 wt. % H2O at 150 MPa enhanced densification and give a relative ρ ˜76.8% and εr ˜ 8.31 but with a Qf of only ˜ 900 GHz. The addition of (NH4)6Mo7O24·4H2O further improved densification to give a relative ρ ˜ 83.7% after annealing at 700 °C, resulting in a εr ˜ 9.91 with a Qf ˜ 11,800 GHz. We conclude therefore that oxides that are difficult to be sintered via a conventional solid state route may benefit from cold sintering but despite the higher density, lower Qf cannot be avoided due to the impurities and grain boundary phases that are introduced
On the kinks and dynamical phase transitions of alpha-helix protein chains
Heuristic insights into a physical picture of Davydov's solitonic model of
the one-dimensional protein chain are presented supporting the idea of a
non-equilibrium competition between the Davydov phase and a complementary,
dynamical- `ferroelectric' phase along the chainComment: small latex file with possible glue problems, just go on !, no
figures, small corrections with respect to the published text, follow-up work
to cond-mat/9304034 [PRE 47 (June 1993) R3818
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
Analytic Lifshitz black holes in higher dimensions
We generalize the four-dimensional R^2-corrected z=3/2 Lifshitz black hole to
a two-parameter family of black hole solutions for any dynamical exponent z and
for any dimension D. For a particular relation between the parameters, we find
the first example of an extremal Lifshitz black hole. An asymptotically
Lifshitz black hole with a logarithmic decay is also exhibited for a specific
critical exponent depending on the dimension. We extend this analysis to the
more general quadratic curvature corrections for which we present three new
families of higher-dimensional D>=5 analytic Lifshitz black holes for generic
z. One of these higher-dimensional families contains as critical limits the z=3
three-dimensional Lifshitz black hole and a new z=6 four-dimensional black
hole. The variety of analytic solutions presented here encourages to explore
these gravity models within the context of non-relativistic holographic
correspondence.Comment: 14 page
Ultraviolet emission of silicon quantum tips
Silicon tips used as field emitters have dimensions that are within the quantum confinement regime. Therefore they can be considered as freestanding silicon tips. In this letter, a photoluminescence spectrum of a 100×100100×100 array of silicon tips was taken at 10 K. Narrow ultraviolet luminescence peaks were observed. Using the empirical pseudopotential homojunction model, it is demonstrated that these luminescence peaks come from energy levels arising from quantum confinement. By fitting the theoretical result to the experimental result, we conclude that the luminescence peaks come from Si quantum tips of about 20 Å in width and that they are covered by silicon dioxide. © 1999 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71101/2/APPLAB-74-3-386-1.pd
Preliminary Observations on the Effects In Vivo and In Vitro of Low Dose Laser on the Epithelia of the Bladder, Trachea and Tongue of the Mouse
The effects of low dose CW laser were studied by in vivo and in vitro systems. The experimental tissues that were used included bladders, tracheas and tongues as experimental tissues. Buddings (round surface projections) from the transitional epithelium of bladder were frequently observed 3 days after laser treatment in both in vivo and in vitro systems. The trachea and tongue were less affected. In both the in vivo and in vitro systems, some epithelial cells of the trachea showed decreased microvilli and cilia 3 days after treatment whereas the epithelial cells of the tongue revealed no response to laser treatment in both systems. Low dose laser, however, appeared to promote the rate of healing of experimental tongue ulcer: healing was about 1 day earlier in the laser treated than non-treated animals and vessel infiltration and epithelialization were detected earlier in the treated
Solution of two channel spin-flavor Kondo model
We investigate a model where an impurity couples to both the spin and the
flavor currents of the two channel conduction electrons. This model can be used
as a prototype model of a magnetic impurity tunneling between two sites in a
metal and of some heavy fermion systems where the ground state of the impurity
has a fourfold degeneracy. The system is shown to flow to a doubly degenerate
non fermi-liquid(NFL) fixed point; the thermodynamic quantities show NFL
behaviors, but the transport quantities show fermi liquid (FL) behaviors . A
spin-flavor coupling double tensor term is shown to drive the system to one of
the two singlet FL fixed points. The relation with SU(4) Coqblin-Schrieffer
model is studied. The implications on the possible experiments are given.Comment: 11 pages, REVTEX, no figures. To appear in Phys. Rev. B (Rapid Comm.)
July 1, 199
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