56 research outputs found
Anti-Stokes Excitation of Solid-State Quantum Emitters for Nanoscale Thermometry
© 2019 The Author(s) 2019 OSA. We report the first demonstration of Anti-Stokes excitation on a single solid-state quantum emitter-namely the germanium-vacancy center in diamond and its application as a high-sensitive nanoscale thermal sensor
Direct WIMP identification: Physics performance of a segmented noble-liquid target immersed in a Gd-doped water veto
We evaluate background rejection capabilities and physics performance of a
detector composed of two diverse elements: a sensitive target (filled with one
or two species of liquefied noble gasses) and an active veto (made of Gd-doped
ultra-pure water). A GEANT4 simulation shows that for a direct WIMP search,
this device can reduce the neutron background to O(1) event per year per tonne
of material. Our calculation shows that an exposure of one tonne year
will suffice to exclude spin-independent WIMP-nucleon cross sections ranging
from pb to pb.Comment: 17 pages, 5 figures. Version accepted for publication in JCA
Near‐Field Energy Transfer between a Luminescent 2D Material and Color Centers in Diamond
Energy transfer between fluorescent probes lies at the heart of many
applications ranging from bio-sensing and -imaging to enhanced photo-detection
and light harvesting. In this work, we study F\"orster resonance energy
transfer (FRET) between shallow defects in diamond --- nitrogen-vacancy (NV)
centers --- and atomically-thin, two-dimensional materials --- tungsten
diselenide (WSe). By means of fluorescence lifetime imaging, we demonstrate
the occurrence of FRET in the WSe/NV system. Further, we show that in the
coupled system, NV centers provide an additional excitation pathway for WSe
photoluminescence. Our results constitute the first step towards the
realization of hybrid quantum systems involving single-crystal diamond and
two-dimensional materials that may lead to new strategies for studying and
controlling spin transfer phenomena and spin valley physics
Topological Defects in Nematic Droplets of Hard Spherocylinders
Using computer simulations we investigate the microscopic structure of the
singular director field within a nematic droplet. As a theoretical model for
nematic liquid crystals we take hard spherocylinders. To induce an overall
topological charge, the particles are either confined to a two-dimensional
circular cavity with homeotropic boundary or to the surface of a
three-dimensional sphere. Both systems exhibit half-integer topological point
defects. The isotropic defect core has a radius of the order of one particle
length and is surrounded by free-standing density oscillations. The effective
interaction between two defects is investigated. All results should be
experimentally observable in thin sheets of colloidal liquid crystals.Comment: 13 pages, 16 figures, Phys. Rev.
The Real Gauge Singlet Scalar Extension of Standard Model: A Possible Candidate of Cold Dark Matter
We consider a simplest extension of Standard Model in which a real SM gauge
singlet scalar with an additional discrete symmetry is introduced to SM.
This additional scalar can be a viable candidate of cold dark matter since the
stability of is achieved by the application of symmetry on .
Considering as a possible candidate of cold dark matter we have solved
Boltzmann's equation to find the freeze out temperature and relic density of
for Higgs mass 120 GeV in the scalar mass range 5 GeV to 1 TeV. As
coupling appearing in Lagrangian depends upon the value of scalar
mass and Higgs mass , we have constrained the
parameter space by using the WMAP limit on the relic density of dark matter in
the universe and the results of recent ongoing dark matter direct search
experiments namely CDMS-II, CoGeNT, DAMA, EDELWEISS-II, XENON-10, XENON-100.
From such analysis we find two distinct mass regions (a lower and higher mass
domain) for such a dark matter candidate that satisfy both the WMAP limit and
the experimental results considered here. We have estimated the possible
differential direct detection rates and annual variation of total detection
rates for this scalar dark matter candidate for two detector materials
namely Ge, Xe. Finally we have calculated the ray flux from the
galactic centre due to annihilation of two 130 GeV scalar dark matter into two
monoenergetic rays.Comment: 21 pages, New calculations, figures and references adde
Sensitivity and Insensitivity of Galaxy Cluster Surveys to New Physics
We study the implications and limitations of galaxy cluster surveys for
constraining models of particle physics and gravity beyond the Standard Model.
Flux limited cluster counts probe the history of large scale structure
formation in the universe, and as such provide useful constraints on
cosmological parameters. As a result of uncertainties in some aspects of
cluster dynamics, cluster surveys are currently more useful for analyzing
physics that would affect the formation of structure than physics that would
modify the appearance of clusters. As an example we consider the Lambda-CDM
cosmology and dimming mechanisms, such as photon-axion mixing.Comment: 24 pages, 8 eps figures. References added, discussion of scatter in
relations between cluster observables lengthene
Autistic children's language imitation shows reduced sensitivity to ostracism
In dialogue, speakers tend to imitate, or align with, a partner’s language choices. Higher levels of alignment facilitate communication and can be elicited by affiliation goals. Since autistic children have interaction and communication impairments, we investigated whether a failure to display affiliative language imitation contributes to their conversational difficulties. We measured autistic children’s lexical alignment with a partner, following an ostracism manipulation which induces affiliative motivation in typical adults and children. While autistic children demonstrated lexical alignment, we observed no affiliative influence on ostracised children’s tendency to align, relative to controls. Our results suggest that increased language imitation—a potentially valuable form of social adaptation—is unavailable to autistic children, which may reflect their impaired affective understanding
A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)
Meeting abstrac
Quantum Energy and Charge Transfer at Two-Dimensional Interfaces.
Energy and charge transfer processes in interacting donor-acceptor systems are the bedrock of many fundamental studies and technological applications ranging from biosensing to energy storage and quantum optoelectronics. Central to the understanding and utilization of these transfer processes is having full control over the donor-acceptor distance. With their atomic thickness and ease of integrability, two-dimensional materials are naturally emerging as an ideal platform for the task. Here, we review how van der Waals semiconductors are shaping the field. We present a selection of some of the most significant demonstrations involving transfer processes in layered materials that deepen our understanding of transfer dynamics and are leading to intriguing practical realizations. Alongside current achievements, we discuss outstanding challenges and future opportunities
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