1,414 research outputs found
Qutrit Dichromatic Calculus and Its Universality
We introduce a dichromatic calculus (RG) for qutrit systems. We show that the
decomposition of the qutrit Hadamard gate is non-unique and not derivable from
the dichromatic calculus. As an application of the dichromatic calculus, we
depict a quantum algorithm with a single qutrit. Since it is not easy to
decompose an arbitrary d by d unitary matrix into Z and X phase gates when d >
2, the proof of the universality of qudit ZX calculus for quantum mechanics is
far from trivial. We construct a counterexample to Ranchin's universality
proof, and give another proof by Lie theory that the qudit ZX calculus contains
all single qudit unitary transformations, which implies that qudit ZX calculus,
with qutrit dichromatic calculus as a special case, is universal for quantum
mechanics.Comment: In Proceedings QPL 2014, arXiv:1412.810
Stochastic Block Coordinate Frank-Wolfe Algorithm for Large-Scale Biological Network Alignment
With increasingly "big" data available in biomedical research, deriving
accurate and reproducible biology knowledge from such big data imposes enormous
computational challenges. In this paper, motivated by recently developed
stochastic block coordinate algorithms, we propose a highly scalable randomized
block coordinate Frank-Wolfe algorithm for convex optimization with general
compact convex constraints, which has diverse applications in analyzing
biomedical data for better understanding cellular and disease mechanisms. We
focus on implementing the derived stochastic block coordinate algorithm to
align protein-protein interaction networks for identifying conserved functional
pathways based on the IsoRank framework. Our derived stochastic block
coordinate Frank-Wolfe (SBCFW) algorithm has the convergence guarantee and
naturally leads to the decreased computational cost (time and space) for each
iteration. Our experiments for querying conserved functional protein complexes
in yeast networks confirm the effectiveness of this technique for analyzing
large-scale biological networks
Critical phenomena in gravitational collapse of Husain-Martinez-Nunez scalar field
We construct analytical models to study the critical phenomena in
gravitational collapse of the Husain-Martinez-Nunez massless scalar field. We
first use the cut-and-paste technique to match the conformally flat solution
( ) onto an outgoing Vaidya solution. To guarantee the continuity of the
metric and the extrinsic curvature, we prove that the two solutions must be
joined at a null hypersurface and the metric function in Vaidya spacetime must
satisfy some constraints. We find that the mass of the black hole in the
resulting spacetime takes the form , where the
critical exponent is equal to . For the case , we show
that the scalar field must be joined onto two pieces of Vaidya spacetimes to
avoid a naked singularity. We also derive the power-law mass formula with
. Compared with previous analytical models constructed from a
different scalar field with continuous self-similarity, we obtain the same
value of . However, we show that the solution with is not
self-similar. Therefore, we provide a rare example that a scalar field without
self-similarity also possesses the features of critical collapse.Comment: 14 pages, 6 figure
Negative Transfer of Chinese in English Learnersâ Lexical Learning: A Markedness Theory Perspective
Based on the markedness theory, the article discusses the negative transfer of Chinese in English learnersâ lexical learning from the morphological, semantic and pragmatic perspectives, proposes that raising the English learnersâ markedness awareness and encouraging the students to read extensively to enhance their communicative competence facilitates overcoming the negative transfer
Cultivating Online English Learner Autonomy in Internet Plus Era: A DST Perspective
Based on Dynamic Systems Theory (DST), the article proposes that cultivating online English learner autonomy is a complex dynamic system. Under the interactions of learners, learning resources, learning task and learning environment, the development of online English learner autonomy is featured with being non-linearity, self-organization and âbutterfly effectsâ. It proposes that in internet plus era, online English learner autonomy can be improved in resource-based, technology-based, student-based and teacher-based approach
Size and shape specific particles toward biomedical imaging: design, fabrication, and characterization
Thesis (Ph.D.)--Boston UniversityThe power of a biomedical imaging modality can be augmented and is, in large part, determined by the capabilities of the available contrast agents. For example, quantum dots represent a colorful palette of powerful contrast agents for optical fluorescence imaging and Raman spectroscopy, given their tunable multiplexing capability and long-term stability compared to traditional organic molecule-based fluorescent labels. On the contrary, as the workhorses in both clinical and research imaging, the full potentials of magnetic resonance imaging and computed tomography have yet to be actualized due to several existing fundamental limitations in the currently available contrast agents, including but not limited to, the lack of multiplexing capability, low sensitivity, as well as the lack of functional imaging capacity. Leveraging both traditional top-down micro- and nanoelectromechanical systems fabrication techniques and bottom-up self-assembly approaches, this dissertation explores the possibility of mitigating these limitations by engineering precisely controllable, size and shape (as well as a host of other materials properties) specific micro- and nanoparticles, for use as the next generation contrast agents for magnetic resonance imaging and computed tomography.
Herein, the ways by which engineering approaches can impact the design, fabrication and characterization of contrast agents is investigated. Specifically, different configmations of magnetic micro- and nanoparticles, including double-disk and hollow-cylinder structmes, fabricated using a top-down approach were employed as magnetic resonance imaging contrast agents enabled with a multiplexing capability and improved sensitivity. Subsequently, a scalable nanomanufactming platform, utilizing nanoporous anodized aluminum oxide membranes as templates for pattern transfer as well as thermal/ultraviolet nanoimprinting techniques, was developed for the high throughput fabrication of size and shape specific polymeric nanorods. When ladened with X-ray attenuating tantalum oxide nanoparticle payloads, these polymeric nanorods can be used as contrast agents for computed tomography, yielding prolonged vascular circulation times, improved sensitivity, as well as targeted imaging capabilities. Furthermore, by applying various payload materials, this nanomanufacturing platform also has the flexibility to produce contrast agents for other imaging modalities, as well as the potential to realize dual-purpose agents for both diagnostic and therapeutic applications
Charm Production in Deep Inelastic Scattering from Threshold to High $Q^{2}
Charm final states in deep inelastic scattering constitute of the
inclusive cross-section at small as measured at HERA. These data can reveal
important information on the charm and gluon structure of the nucleon if they
are interpreted in a consistent perturbative QCD framework which is valid over
the entire energy range from threshold to the high energy limit. We describe in
detail how this can be carried out order-by-order in PQCD in the generalized
\msbar formalism of Collins (generally known as the ACOT approach), and
demonstrate the inherent smooth transition from the 3-flavor to the 4-flavor
scheme in a complete order calculation, using a Monte Carlo
implementation of this formalism. This calculation is accurate to the same
order as the conventional NLO calculation in the limit . It includes the resummed large logarithm contributions of the 3-flavor
scheme (generally known in this context as the fixed-flavor-number or FFN
scheme) to all orders of . For the inclusive structure
function, comparison with recent HERA data and the existing FFN calculation
reveals that the relatively simple order- (NLO) 4-flavor () calculation can, in practice, be extended to rather low energy scales,
yielding good agreement with data over the full measured range. The Monte
Carlo implementation also allows the calculation of differential distributions
with relevant kinematic cuts. Comparisons with available HERA data show
qualitative agreement; however, they also indicate the need to extend the
calculation to the next order to obtain better description of the differential
distributions.Comment: 22 pages (LATEX), 8 figures (EPS); A few clarifying changes made;
version published in JHE
An Aircraft Ranging Algorithm Based on Two Frames of Image in Monocular Image Sequence
We proposed a novel rotation-invariant feature based passive ranging algorithm to estimate the distance of an imaged non-cooperation target to camera. This improved algorithm avoids sometimes occurrence of physically unreasonable results in solving the existing quartic equation, such as the happening of complex or negative value. This method uses three matched points in two adjacent frames of an image sequence to extract depth-dependent line features of the target. With this line features combination of the observerâs displacement and imaging directions, a quadratic equation was build to estimate the distance. Analysis shows that the proposed new passive ranging equation would be solvable when the observer is with non-zero displacement in adjacent sampling instances. Our reduced-model experiment also demonstrates that the proposed algorithm is not only simple and feasible but also with a relative ranging error no more than 4 per cent in most cases.Defence Science Journal, Vol. 64, No. 1, January 2014, DOI:10.14429/dsj.64.288
Numerical simulation of clouds and precipitation depending on different relationships between aerosol and cloud droplet spectral dispersion
The aerosol effects on clouds and precipitation in deep convective cloud systems are investigated using the Weather Research and Forecast (WRF) model with the Morrison two-moment bulk microphysics scheme. Considering positive or negative relationships between the cloud droplet number concentration (Nc) and spectral dispersion (É), a suite of sensitivity experiments are performed using an initial sounding data of the deep convective cloud system on 31 March 2005 in Beijing under either a maritime (âcleanâ) or continental (âpollutedâ) background. Numerical experiments in this study indicate that the sign of the surface precipitation response induced by aerosols is dependent on the ÉâNc relationships, which can influence the autoconversion processes from cloud droplets to rain drops. When the spectral dispersion É is an increasing function of Nc, the domain-average cumulative precipitation increases with aerosol concentrations from maritime to continental background. That may be because the existence of large-sized rain drops can increase precipitation at high aerosol concentration. However, the surface precipitation is reduced with increasing concentrations of aerosol particles when É is a decreasing function of Nc. For the ÉâNc negative relationships, smaller spectral dispersion suppresses the autoconversion processes, reduces the rain water content and eventually decreases the surface precipitation under polluted conditions. Although differences in the surface precipitation between polluted and clean backgrounds are small for all the ÉâNc relationships, additional simulations show that our findings are robust to small perturbations in the initial thermal conditions.
Keywords: aerosol indirect effects, cloud droplet spectral dispersion, autoconversion parameterization, deep convective systems, two-moment bulk microphysics schem
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