329 research outputs found
Running demands in New Zealand club, semi-professional and professional rugby union competitions
Game demands of professional rugby players are well documented, however, there is minimal research on the running demands in amateur and semi-professional competitions. To the authors knowledge, no research has compared the running demands in club, national (division 1 (NPC) and division 2 (Heartland)) or international provincial (Super rugby) competitions. Information on the running demands of each competition would enable trainers to develop training programs specific to player’s needs and assist in the transition of players between competitions. Players from a team in each competition level wore a 10 Hz GPS unit during all games in a rugby season. Total distance (m), running distance (≥7 km.h-1(m)) and high intensity running (≥16 km.h-1(m)) were recorded. The research was approved by an Institutional Ethics Board and the NZ Rugby Union. Lower competition (club and division 2) players covered greater distances (150m to 400m) per game than higher level players. As in total distance, division 2 players ran (≥7 km.h-1) more in games (120m) compared to higher level players. However, club players typically covered less running distance than higher level players (3102m vs 3237 to 3319m, p=0.10 to 0.00). In contrast, Super rugby players typically ran greater distances (962m) at higher speeds (≥16 km.h-1) per game. This information could assist in the development of competition-specific training programs, and the monitoring of training loads during a season and when a player returns from an injury. Further analysis will investigate running demands of rugby positions in each competition to enable the development of position-specific-training programs
Mitigation of Nitrogen Vacancy Ionization from Material Integration for Quantum Sensing
The nitrogen-vacancy (NV) color center in diamond has demonstrated great
promise in a wide range of quantum sensing. Recently, there have been a series
of proposals and experiments using NV centers to detect spin noise of quantum
materials near the diamond surface. This is a rich complex area of study with
novel nano-magnetism and electronic behavior, that the NV center would be ideal
for sensing. However, due to the electronic properties of the NV itself and its
host material, getting high quality NV centers within nanometers of such
systems is challenging. Band bending caused by space charges formed at the
metal-semiconductor interface force the NV center into its insensitive charge
states. Here, we investigate optimizing this interface by depositing thin metal
films and thin insulating layers on a series of NV ensembles at different
depths to characterize the impact of metal films on different ensemble depths.
We find an improvement of coherence and dephasing times we attribute to
ionization of other paramagnetic defects. The insulating layer of alumina
between the metal and diamond provide improved photoluminescence and higher
sensitivity in all modes of sensing as compared to direct contact with the
metal, providing as much as a factor of 2 increase in sensitivity, decrease of
integration time by a factor of 4, for NV relaxometry measurements
High-fidelity single-shot readout for a spin qubit via an enhanced latching mechanism
The readout of semiconductor spin qubits based on spin blockade is fast but
suffers from a small charge signal. Previous work suggested large benefits from
additional charge mapping processes, however uncertainties remain about the
underlying mechanisms and achievable fidelity. In this work, we study the
single-shot fidelity and limiting mechanisms for two variations of an enhanced
latching readout. We achieve average single-shot readout fidelities > 99.3% and
> 99.86% for the conventional and enhanced readout respectively, the latter
being the highest to date for spin blockade. The signal amplitude is enhanced
to a full one-electron signal while preserving the readout speed. Furthermore,
layout constraints are relaxed because the charge sensor signal is no longer
dependent on being aligned with the conventional (2, 0) - (1, 1) charge dipole.
Silicon donor-quantum-dot qubits are used for this study, for which the dipole
insensitivity substantially relaxes donor placement requirements. One of the
readout variations also benefits from a parametric lifetime enhancement by
replacing the spin-relaxation process with a charge-metastable one. This
provides opportunities to further increase the fidelity. The relaxation
mechanisms in the different regimes are investigated. This work demonstrates a
readout that is fast, has one-electron signal and results in higher fidelity.
It further predicts that going beyond 99.9% fidelity in a few microseconds of
measurement time is within reach.Comment: Supplementary information is included with the pape
Fabrication of thin diamond membranes by Ne implantation
Color centers in diamond are one of the most promising tools for quantum
information science. Of particular interest is the use of single-crystal
diamond membranes with nanoscale-thickness as hosts for color centers. Indeed,
such structures guarantee a better integration with a variety of other quantum
materials or devices, which can aid the development of diamond-based quantum
technologies, from nanophotonics to quantum sensing. A common approach for
membrane production is what is known as "smart-cut", a process where membranes
are exfoliated from a diamond substrate after the creation of a thin
sub-surface amorphous carbon layer by He implantation. Due to the high ion
fluence required, this process can be time-consuming. In this work, we
demonstrated the production of thin diamond membranes by neon implantation of
diamond substrates. With the target of obtaining membranes of 200 nm
thickness and finding the critical damage threshold, we implanted different
diamonds with 300 keV Ne ions at different fluences. We characterized the
structural properties of the implanted diamonds and the resulting membranes
through SEM, Raman spectroscopy, and photoluminescence spectroscopy. We also
found that a SRIM model based on a two-layer diamond/sp-carbon target
better describes ion implantation, allowing us to estimate the diamond critical
damage threshold for Ne implantation. Compared to He smart-cut, the use
of a heavier ion like Ne results in a ten-fold decrease in the ion fluence
required to obtain diamond membranes and allows to obtain shallower smart-cuts,
i.e. thinner membranes, at the same ion energy
Excitonic condensate and quasiparticle transport in electron-hole bilayer systems
Bilayer electron-hole systems undergo excitonic condensation when the
distance d between the layers is smaller than the typical distance between
particles within a layer. All excitons in this condensate have a fixed dipole
moment which points perpendicular to the layers, and therefore this condensate
of dipoles couples to external electromagnetic fields. We study the transport
properties of this dipolar condensate system based on a phenomenological model
which takes into account contributions from the condensate and quasiparticles.
We discuss, in particular, the drag and counterflow transport, in-plane
Josephson effect, and noise in the in-plane currents in the condensate state
which provides a direct measure of the superfluid collective-mode velocity.Comment: 7 pages, 3 figure
Cosmic Histories of Stars, Gas, Heavy Elements, and Dust
We present a set of coupled equations that relate the stellar, gaseous,
chemical, and radiation constituents of the universe averaged over the whole
galaxy population. Using as input the available data from quasar
absorption-line surveys, optical imaging and redshift surveys, and the COBE
DIRBE and FIRAS extragalactic infrared background measurements, we obtain
solutions for the cosmic histories of stars, interstellar gas, heavy elements,
dust, and radiation from stars and dust in galaxies. Our solutions reproduce
remarkably well a wide variety of observations that were not used as input,
including the integrated background light from galaxy counts, the optical and
near-infrared emissivities from galaxy surveys, the local infrared emissivities
from the IRAS survey, the mean abundance of heavy elements from surveys of
damped Lyman-alpha systems, and the global star formation rates from H
surveys and submillimeter observations. The solutions presented here suggest
that the process of galaxy formation appears to have undergone an early period
of substantial inflow to assemble interstellar gas at , a subsequent
period of intense star formation and chemical enrichment at , and a recent period of rapid decline in the gas content, star
formation rate, optical stellar emissivity, and infrared dust emission at
. [abridged version]Comment: 29 pages, ApJ in press, 10 Sept 9
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