Search results for "Algorithms"
showing 10 items of 1716 documents
Quantum algorithm complexity
2008
Elektroniskā versija nesatur pielikumus
Ultrametric Vs. Quantum Query Algorithms
2014
Ultrametric algorithms are similar to probabilistic algorithms but they describe the degree of indeterminism by p-adic numbers instead of real numbers. This paper introduces the notion of ultrametric query algorithms and shows an example of advantages of ultrametric query algorithms over deterministic, probabilistic and quantum query algorithms.
Quantum query algorithms for certain functions and general algorithm construction techniques
2007
Quantum algorithms can be analyzed in a query model to compute Boolean functions where input is given in a black box, but the aim is to compute function value for arbitrary input using as few queries as possible. In this paper we concentrate on quantum query algorithm designing tasks. The main aim of research was to find new efficient algorithms and develop general algorithm designing techniques. We present several exact quantum query algorithms for certain problems that are better than classical counterparts. Next we introduce algorithm transformation methods that allow significant enlarging of sets of exactly computable functions. Finally, we propose quantum algorithm designing methods. G…
Energy dependence of the differences between the quark and gluon jet fragmentation
1996
Three jet events arising from decays of the Z beson, collected by the DELPHI detector, were used to measure differences in quark and gluon fragmentation. Gluon jets were anti-tagged by identifying b quark jets. Unbiased quark jets came from events with two jets plus one photon. Quark and gluon jet properties in different energy ranges were compared for the first time within the same detector. Quark and gluon jets of nearly the same energy in symmetric three jet event topologies were also compared. Using three independent methods, the average value of the ratio of the mean charged multiplicities of gluon and quark jets is [ r ] = 1.241 +/- 0.015 (stat.) +/- 0.025 (syst.). Gluon jets are broa…
Scalar quark searches in $e^+ e^-$ collisions at $\sqrt{s}$ = 181-184 GeV
1998
Searches for scalar top, scalar bottom and degenerate scalar quarks have been performed with data collected with the ALEPH detector at LEP. The data sample consists of 57 pb^-1 taken at sqrt{s} = 181-184 GeV. No evidence for scalar top, scalar bottom or degenerate scalar quarks was found in the channels tilde{t} --> c chi, tilde{t} --> b l snu, tilde{b} --> b chi, and tilde{q} --> q chi. From the channel tilde{t} --> c chi a limit of 74 GeV/c^2 has been set on the scalar top quark mass, independent of the mixing angle. This limit assumes a mass difference between the stop and the chi in the range 10-40 GeV/c^2. From the channel tilde{t} --> b l snu the mixing-angle-indepen…
Search for pair production of the scalar top quark in muon+tau final states
2012
We present a search for the pair production of scalar top quarks ($\tilde{t}_{1}$), the lightest supersymmetric partners of the top quarks, in $p\bar{p}$ collisions at a center-of-mass energy of 1.96 TeV, using data corresponding to an integrated luminosity of {7.3 $fb^{-1}$} collected with the \dzero experiment at the Fermilab Tevatron Collider. Each scalar top quark is assumed to decay into a $b$ quark, a charged lepton, and a scalar neutrino ($\tilde{\nu}$). We investigate final states arising from $\tilde{t}_{1} \bar{\tilde{t}_{1}} \rightarrow b\bar{b}\mu\tau \tilde{\nu} \tilde{\nu}$ and $\tilde{t}_{1} \bar{\tilde{t}_{1}} \rightarrow b\bar{b}\tau\tau \tilde{\nu} \tilde{\nu}$. With no si…
Search for Pair Production of Supersymmetric Top Quarks in Dilepton Events frompp¯Collisions ats=1.96 TeV
2010
We present the results of a search for pair production of the supersymmetric partner of the top quark (the top squark (t) over tilde (1)) decaying to a b quark and a chargino (chi) over tilde (+/-)(1) with a subsequent (chi) over tilde (+/-)(1) decay into a neutralino (chi) over tilde (0)(1), lepton l, and neutrino nu Using a data sample corresponding to 2.7 fb(-1) of integrated luminosity of p (p) over bar collisions at root s = 1: 96 TeV collected by the CDF II detector, we reconstruct the mass of top squark candidate events and fit the observed mass spectrum to a combination of standard model processes and (t) over tilde (1)(t) over tilde (1). We find no evidence for (t) over tilde (1)(t…
A combined molecular dynamics and Monte Carlo study of the approach towards phase separation in colloid-polymer mixtures.
2011
A coarse-grained model for colloid-polymer mixtures is investigated where both colloids and polymer coils are represented as point-like particles interacting with spherically symmetric effective potentials. Colloid-colloid and colloid-polymer interactions are described by Weeks-Chandler-Andersen potentials, while the polymer-polymer interaction is very soft, of strength k(B)T/2 for maximum polymer-polymer overlap. This model can be efficiently simulated both by Monte Carlo and molecular dynamics methods, and its phase diagram closely resembles that of the well-known Asakura-Oosawa model. The static and dynamic properties of the model are presented for systems at critical colloid density, va…
The modulation transfer function and signal-to-noise ratio of different digital filters: a technical approach.
2011
The aim of this study was to illustrate the influence of digital filters on the signal-to-noise ratio (SNR) and modulation transfer function (MTF) of digital images. The article will address image pre-processing that may be beneficial for the production of clinically useful digital radiographs with lower radiation dose.Three filters, an arithmetic mean filter, a median filter and a Gaussian filter (standard deviation (SD) = 0.4), with kernel sizes of 3 × 3 pixels and 5 × 5 pixels were tested. Synthetic images with exactly increasing amounts of Gaussian noise were created to gather linear regression of SNR before and after application of digital filters. Artificial stripe patterns with defin…
Numerical expressions for the computation of coincidence-summing correction factors in γ-ray spectrometry with HPGe detectors
2009
Numerical expressions to compute gamma-gamma and gamma-X(K) coincidence summing corrections were deduced by using a suitable computer program and a matrix representation of a decay scheme. For point sources only full-energy peak and total efficiencies are needed. Alternatively, values of peak-to-total ratio can be introduced. For extended sources, the same expressions can be considered with the introduction of "effective efficiencies". Examples of the use of the expressions for point sources and a particulate filter sample measured with a 60% relative efficiency HPGe detector are reported.