246 research outputs found
Waveguide photonic limiters based on topologically protected resonant modes
We propose a concept of chiral photonic limiters utilising topologically
protected localised midgap defect states in a photonic waveguide. The chiral
symmetry alleviates the effects of structural imperfections and guaranties a
high level of resonant transmission for low intensity radiation. At high
intensity, the light-induced absorption can suppress the localised modes, along
with the resonant transmission. In this case the entire photonic structure
becomes highly reflective within a broad frequency range, thus increasing
dramatically the damage threshold of the limiter. Here we demonstrate
experimentally the principle of operation of such photonic structures using a
waveguide consisting of coupled dielectric microwave resonators.Comment: 6 pages, 4 figure
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Sheltering the Dream and Protecting the Dreamer : The Role of Place and Space in the Online Interactions of Fiction Authors and Readers
Fiction authors and readers have traditionally interacted through the mediation of a 3rd party (e.g. a publisher or agent), at events such as book signings or author readings. Held in physical spaces (e.g. bookshops or libraries), these events enable authors to discuss their book, and readers to ask them questions. In recent years, online social networking sites have introduced a new environment for direct, two-way interactions without this traditional mediation. Our understanding of how this change impacts authors and readers, and the role technology now plays as mediator, is currently limited. This paper describes a qualitative interview study held with six authors and six readers of Genre Fiction. The study revealed that neither party sees great benefit to interacting directly online - a finding partially explainable by the differences in how physical places and online spaces are structured to support their interactions. We drew on space and place research to develop an HCI perspective of the impact of this change. This paper contributes an enriched understanding of fiction author and reader interactions; in particular why they do not often interact directly - or wish to. We also demonstrate the usefulness of space and place theory in understanding the boundaries which divide author and reader
Iterative algorithm versus analytic solutions of the parametrically driven dissipative quantum harmonic oscillator
We consider the Brownian motion of a quantum mechanical particle in a
one-dimensional parabolic potential with periodically modulated curvature under
the influence of a thermal heat bath. Analytic expressions for the
time-dependent position and momentum variances are compared with results of an
iterative algorithm, the so-called quasiadiabatic propagator path integral
algorithm (QUAPI). We obtain good agreement over an extended range of
parameters for this spatially continuous quantum system. These findings
indicate the reliability of the algorithm also in cases for which analytic
results may not be available a priori.Comment: 15 pages including 11 figures, one reference added, minor typos
correcte
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“Webcomics Archive? Now I’m Interested”: Comics Readers Seeking Information in Web Archives
There is a longstanding tradition of understanding information needs and interaction behavior across different user groups to inform the design of digital products and services. There is a gap in such research of comics readers, specifically how they seek and interact with the information and interfaces of web-based archives provided by cultural institutions. For example, while information interaction research has now recognized that information-seeking for leisure and pleasure are important domains of study - consuming information based in fiction can help us escape to exciting worlds by captivating narratives - and while there have been studies of how people find fiction to read, there have to our knowledge been no user-centered studies on how people find and consume digital comics. This exploratory study provides an enriched understanding of the information needs and interaction behaviors of digital comics readers and how that understanding can inform the design of digital platforms to better support them
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"Webcomics Archive? Now I'm Interested": Comics Readers Seeking Information in Web Archives (Poster)
There is a longstanding tradition of understanding information needs and interaction behavior across different user groups to inform the design of digital products and services. There is a gap in such research of comics readers, specifically how they seek and interact with the information and interfaces of web-based archives provided by cultural institutions. For example, while information interaction research has now recognized that information-seeking for leisure and pleasure are important domains of study - consuming information based in fiction can help us escape to exciting worlds by captivating narratives - and while there have been studies of how people find fiction to read, there have to our knowledge been no user-centered studies on how people find and consume digital comics. This exploratory study provides an enriched understanding of the information needs and interaction behaviors of digital comics readers and how that understanding can inform the design of digital platforms to better support them
Bacteriology and Antimicrobial Susceptibility Patterns of Childhood Acute Bacterial Conjunctivitis in Western Greece
Acute bacterial conjunctivitis is a common, highly contagious infection in children and is usually treated empirically with broad spectrum topical antibiotics. In the current study we investigated bacteriology and antibiotic susceptibility patterns in childhood acute bacterial conjunctivitis in Western Greece. We conducted a retrospective analysis of presumed acute bacterial conjunctivitis cases in ''Karamandaneio'' Pediatric General Hospital of Patras, Western Greece, between February 1, 2013 and January 31, 2018. Specimens from the lower conjunctiva fornix were isolated from 191 cases and outcomes were analyzed to identify the pathogenic bacteria of acute bacterial conjunctivitis and their corresponding antibiotic susceptibility patterns. Patients were divided into 3 groups; Group A included neonates under 28 days of life, Group B children from 1 month to 2 years and Group C from 2 years to 14 years. Results revealed that Staphylococcus spp., Haemophilus spp. and Streptococcus spp. were the most prevalent pathogens. No significant differences in isolated pathogens were found between the age groups. Antibiotic resistance rates were higher against ampicillin, ceftriaxone, ceftazidime and sulfamethoxazole. Resistance rates to Ciprofloxacin were low while none of the evaluated isolates were resistant to vancomycin. We concluded that predominant pathogens of childhood acute bacterial conjunctivitis in Western Greece were Staphylococcus spp., Haemophilus spp. and Streptococcus spp. Continuous surveillance, focused in distinct geographic areas, is encouraged to prepare more precise protocols of empirical treatment. Epub: October 1, 2019
Phase diffusion as a model for coherent suppression of tunneling in the presence of noise
We study the stabilization of coherent suppression of tunneling in a driven
double-well system subject to random periodic function ``kicks''. We
model dissipation due to this stochastic process as a phase diffusion process
for an effective two-level system and derive a corresponding set of Bloch
equations with phase damping terms that agree with the periodically kicked
system at discrete times. We demonstrate that the ability of noise to localize
the system on either side of the double-well potenital arises from overdamping
of the phase of oscillation and not from any cooperative effect between the
noise and the driving field. The model is investigated with a square wave
drive, which has qualitatively similar features to the widely studied
cosinusoidal drive, but has the additional advantage of allowing one to derive
exact analytic expressions.Comment: 17 pages, 4 figures, submitted to Phys. Rev.
Suppression of decoherence via strong intra-environmental coupling
We examine the effects of intra-environmental coupling on decoherence by
constructing a low temperature spin--spin-bath model of an atomic impurity in a
Debye crystal. The impurity interacts with phonons of the crystal through
anti-ferromagnetic spin-spin interactions. The reduced density matrix of the
central spin representing the impurity is calculated by dynamically integrating
the full Schroedinger equation for the spin--spin-bath model for different
thermally weighted eigenstates of the spin-bath. Exact numerical results show
that increasing the intra-environmental coupling results in suppression of
decoherence. This effect could play an important role in the construction of
solid state quantum devices such as quantum computers.Comment: 4 pages, 3 figures, Revtex fil
Mixing Quantum and Classical Mechanics
Using a group theoretical approach we derive an equation of motion for a
mixed quantum-classical system. The quantum-classical bracket entering the
equation preserves the Lie algebra structure of quantum and classical
mechanics: The bracket is antisymmetric and satisfies the Jacobi identity, and,
therefore, leads to a natural description of interaction between quantum and
classical degrees of freedom. We apply the formalism to coupled quantum and
classical oscillators and show how various approximations, such as the
mean-field and the multiconfiguration mean-field approaches, can be obtained
from the quantum-classical equation of motion.Comment: 31 pages, LaTeX2
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