1,692 research outputs found
Towards semantic software engineering environments
Software tools processing partially common set of data should share an understanding of what these data mean. Since ontologies have been used to express formally a shared understanding of information, we argue that they are a way towards Semantic SEEs. In this paper we discuss an ontology-based approach to tool integration and present ODE, an ontology-based SEE
Quantum dynamics of a high-finesse optical cavity coupled with a thin semi-transparent membrane
We study the quantum dynamics of the cavity optomechanical system formed by a
Fabry-Perot cavity with a thin vibrating membrane at its center. We first
derive the general multimode Hamiltonian describing the radiation pressure
interaction between the cavity modes and the vibrational modes of the membrane.
We then restrict the analysis to the standard case of a single cavity mode
interacting with a single mechanical resonator and we determine to what extent
optical absorption by the membrane hinder reaching a quantum regime for the
cavity-membrane system. We show that membrane absorption does not pose serious
limitations and that one can simultaneously achieve ground state cooling of a
vibrational mode of the membrane and stationary optomechanical entanglement
with state-of-the-art apparatuses.Comment: 14 pages, 7 figure
Quantum dynamics of a vibrational mode of a membrane within an optical cavity
Optomechanical systems are a promising candidate for the implementation of
quantum interfaces for storing and redistributing quantum information. Here we
focus on the case of a high-finesse optical cavity with a thin vibrating
semitransparent membrane in the middle. We show that robust and stationary
optomechanical entanglement could be achieved in the system, even in the
presence of nonnegligible optical absorption in the membrane. We also present
some preliminary experimental data showing radiation-pressure induced optical
bistability.Comment: 6 pages, 2 figures. Work presented at the conference QCMC 2010 held
on 19-23 July 2010 at the University of Queensland, Brisbane, Australi
Optomechanical sideband cooling of a thin membrane within a cavity
We present an experimental study of dynamical back-action cooling of the
fundamental vibrational mode of a thin semitransparent membrane placed within a
high-finesse optical cavity. We study how the radiation pressure interaction
modifies the mechanical response of the vibrational mode, and the experimental
results are in agreement with a Langevin equation description of the coupled
dynamics. The experiments are carried out in the resolved sideband regime, and
we have observed cooling by a factor 350 We have also observed the mechanical
frequency shift associated with the quadratic term in the expansion of the
cavity mode frequency versus the effective membrane position, which is
typically negligible in other cavity optomechanical devices.Comment: 15 pages, 7 figure
Optomechanically induced transparency in membrane-in-the-middle setup at room temperature
We demonstrate the analogue of electromagnetically induced transparency in a
room temperature cavity optomechanics setup formed by a thin semitransparent
membrane within a Fabry-P\'erot cavity. Due to destructive interference, a weak
probe field is completely reflected by the cavity when the pump beam is
resonant with the motional red sideband of the cavity. Under this condition we
infer a significant slowing down of light of hundreds of microseconds, which is
easily tuned by shifting the membrane along the cavity axis. We also observe
the associated phenomenon of electromagnetically induced amplification which
occurs due to constructive interference when the pump is resonant with the blue
sideband.Comment: 5 pages, 4 figure
Trigger-disabling Acquisition System for Quantum Key Distribution failsafe against Self-blinding
Modern single-photon detectors based on avalanche photodiodes offer
increasingly higher triggering speeds, thus fostering their use in several
fields, prominently in the recent area of Quantum Key Distribution. To reduce
the probability of an afterpulse, these detectors are usually equipped with a
circuitry that disables the trigger for a certain time after a positive
detection event, known as dead time. If the acquisition system connected to the
detector is not properly designed, efficiency issues arise when the triggering
rate is faster than the inverse of detector's dead-time. Moreover, when this
happens with two or more detectors used in coincidence, a security risk called
"self-blinding" can jeopardize the distribution of a secret quantum key. In
this paper we introduce a trigger-disabling circuitry based on an FPGA-driven
feedback loop, so to avoid the above-mentioned inconveniences. In the regime of
single-photon-attenuated light, the electronics dynamically accept a trigger
only after detectors' complete recovery from dead-time. This technique proves
useful to work with detectors at their maximum speed and to increase the
security of a quantum key distribution setup.Comment: 5 pages, 3 figures. Version 2 corrected and improve
Trace-Element Distribution on Sulfide Mineralization in Trento Province, NE Italy
Sulfide mineralization in the province of Trento (northeastern Italy) includes various mineral assemblages that are often silver-rich and have been exploited in different phases from the Middle Ages until the 20th century. This study investigates mineralized rocks from three historically important sites (Calisio mount, Erdemolo lake, and the locality of Cinque Valli), providing new analytical data (Inductively Coupled Plasma-Mass Spectrometry on bulk rocks, and Scanning Electron Microscopy on thin sections) that demonstrate that parageneses do not only include galena, chalcopyrite, and sphalerite but also accessory minerals, such as tetrahedrite, tennantite, acanthite, and sulfosalts (matildite/polybasite). This explains the high content of As (up to 278 ppm), Bi (up to 176 ppm), and Sb (up to 691 ppm) that are associated with Pb–Cu–Zn mineralization. Notably, trace-element ratios indicate that, although closely associated from a geographical point of view, the studied sites are not genetically related and have to be referred to in distinct mineralization
events, possibly induced by three diverse magmatic and hydrothermal phases that occurred in the Variscan post-orogenic setting. Besides geological and petrogenetic reconstruction, the new data outline potential geochemical risks, as they reveal a high concentration of elements characterized by marked toxicity that can be transferred into the local soil and water. Therefore, future studies should be devoted to better investigating the metal distribution in the surroundings of ancient mining sites and their geochemical behavior during the weathering processes
A Magnetic Drug Delivery Capsule Based on a Coil Actuation Mechanism
Current Wireless Capsule Endoscopic systems (WCE) provide only diagnostic tools, but in the future, advanced functionalities such as controllable drug delivery could be available for clinicians. This work introduces a Magnetic Drug Delivery Capsule (MDDC). The MDCC is based on a coil actuation mechanism that enables the deployment of a drug chamber from the device body. In this work, we present the prototype design and the results of bench trials that demonstrated the device ability to trigger the drug deployment by characterizing the magnetic field and resulting force
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