2,542 research outputs found
Phonon sidebands of color centers in hexagonal boron nitride
Low temperature photoluminescence spectra of a color center in hexagonal
boron nitride are analyzed. The acoustic phonon sideband can be described by a
deformation coupling proportional to strain to a phonon bath that is
effectively two dimensional. The optical phonon band is described by Frohlich
coupling to the LO-branches, and a deformation coupling proportional to lattice
displacement for the TO-branch. The resonances expressed in the optical band
vary from defect to defect, in some emitters, coupling to out-of-plane
polarized phonons is reported.Comment: 7 pages, 4 fig
Photophysical Properties of Single Photon Emitters in Hexagonal Boron Nitride
The development of photonic based quantum technologies such as quantum encryption and quantum computing is mainly restrained by the quality of single photon emitter. Effects like phonon interaction, emission purity, stability and decoherence are the major issues. So far quantum dots are leading the race in terms of indistinguishability, emission purity and stability but low collection efficiency and operation at cryogenic/low temperature are major roadblocks. Hexagonal-Boron Nitride (hBN) is a 2D material with stable single photon emission even at 800 °C. hBN is an emerging material, attracting interest from a wider research community but information about the identity of the emitting defects is very limited. The aim of this work is to use the experimental techniques to probe the emitter and comment on the possible origins of the emission.Engineering and Physical Sciences Research Council (EPSRC)Engineering and Physical Sciences Research Council (EPSRC
Practical figures of merit and thresholds for entanglement distribution in quantum networks
Before global-scale quantum networks become operational, it is important to
consider how to evaluate their performance so that they can be built to achieve
the desired performance. We propose two practical figures of merit for the
performance of a quantum network: the average connection time and the average
largest entanglement cluster size. These quantities are based on the generation
of elementary links in a quantum network, which is a crucial initial
requirement that must be met before any long-range entanglement distribution
can be achieved and is inherently probabilistic with current implementations.
We obtain bounds on these figures of merit for a particular class of quantum
repeater protocols consisting of repeat-until-success elementary link
generation followed by joining measurements at intermediate nodes that extend
the entanglement range. Our results lead to requirements on quantum memory
coherence times, requirements on repeater chain lengths in order to surpass the
repeaterless rate limit, and requirements on other aspects of quantum network
implementations. These requirements are based solely on the inherently
probabilistic nature of elementary link generation in quantum networks, and
they apply to networks with arbitrary topology.Comment: 17 pages, 7 figures. v2: extensively revised and rewritten. Title and
abstract modified; added a section on overcoming the repeaterless rate limit;
modified statement of Theorem 1. v3: minor changes to match the published
versio
Smart Asset Management for Electric Utilities: Big Data and Future
This paper discusses about future challenges in terms of big data and new
technologies. Utilities have been collecting data in large amounts but they are
hardly utilized because they are huge in amount and also there is uncertainty
associated with it. Condition monitoring of assets collects large amounts of
data during daily operations. The question arises "How to extract information
from large chunk of data?" The concept of "rich data and poor information" is
being challenged by big data analytics with advent of machine learning
techniques. Along with technological advancements like Internet of Things
(IoT), big data analytics will play an important role for electric utilities.
In this paper, challenges are answered by pathways and guidelines to make the
current asset management practices smarter for the future.Comment: 13 pages, 3 figures, Proceedings of 12th World Congress on
Engineering Asset Management (WCEAM) 201
Morphea (Localized Scleroderma) Presenting With Recurrent Skin and Soft Tissue Infections: A Diagnostic Dilemma.
Morphea or localized scleroderma is reported to be triggered through diverse stimuli. We present a case of morphea that presented as a non-healing wound with superimposed methicillin-sensitive Staphylococcus aureus (MSSA) infection. In our case, morphea was thought to have been potentially triggered by a post-surgical infection. We discuss the potential infectious triggers and common infections that may confound the diagnosis
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