32,651 research outputs found
On superconformal anyons
In d=2+1 dimensions, there exist field theories which are non-relativistic
and superconformal. These theories describe two species of anyons, whose spins
differ by 1/2, interacting in a harmonic trap. We compute the dimensions of
chiral primary operators. These operators receive large anomalous dimensions
which are related to the unusual angular momentum properties of anyons.
Surprisingly, we find that the dimensions of some chiral primary operators
violate the unitarity bound and we trace this to the fact that the associated
wavefunctions become non-normalisable. We also study BPS non-perturbative
states in this theory: these are Jackiw-Pi vortices. We show that these emerge
at exactly the point where perturbative operators hit the unitarity bound. To
describe the low-energy dynamics of these vortices, we construct a novel type
of supersymmetric gauged linear sigma model.This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/JHEP01(2016)13
A matrix model for WZW
We study a U(N) gauged matrix quantum mechanics which, in the large N limit,
is closely related to the chiral WZW conformal field theory. This manifests
itself in two ways. First, we construct the left-moving Kac-Moody algebra from
matrix degrees of freedom. Secondly, we compute the partition function of the
matrix model in terms of Schur and Kostka polynomials and show that, in the
large limit, it coincides with the partition function of the WZW model.
This same matrix model was recently shown to describe non-Abelian quantum Hall
states and the relationship to the WZW model can be understood in this
framework.Science and Technology Facilities Council; European Research Council under the European Union’s Seventh Framework Programme (FP7/2007-2013), ERC grant agreement STG 279943, “Strongly Coupled Systems”This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/JHEP08(2016)00
What are the holistic care impacts among individuals living through the COVID-19 pandemic in residential or community care settings? An integrative systematic review.
The objective of this study was to critically synthesise evidence in relation to the holistic care impacts (physical, psychological, social, spiritual and environmental well-being) among individuals living in residential aged-care facilities (RACFs) with restrictions during the COVID-19 pandemic. An integrative systematic review followed a pre-registered protocol and has been reported according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) Guidelines. Electronic databases were searched from inception to June 2022. Qualitative, quantitative and mixed methods studies were included. All articles were double-screened according to a pre-determined eligibility criterion. The review process was managed using Covidence systematic review software. Data from the studies were extracted, methodological quality appraisal conducted and a narrative synthesis conducted. 18 studies were included. The impact of restrictive practices and periods of lockdown impacted older people on all levels of individual quality-of-life. With or without COVID-19, residents experienced functional decline and many experienced malnutrition, increased incontinence, increased pain, and poorer general health and significant psychological distress. Depression increased with reduced social contact, as did anxiety and loneliness. Some residents spoke of suicidal ideation. It is highly plausible that further outbreaks may prompt knee-jerk reactions from public health departments and governing bodies to continue to restrict and lockdown facilities. Public health COVID-19 outbreak policy for aged care across the globe will need to consider the benefits verses risk debate, given the findings uncovered in this review. These findings showed that it is vital that policy considers quality-of-life domains - not solely survival rates
Predicted efficiency of Si wire array solar cells
Solar cells based on arrays of CVD-grown Si nano- or micro-wires have attracted interest as potentially low-cost alternatives to conventional wafer-based Si photovoltaics [1-6], and single-wire solar cells have been reported with efficiencies of up to 3.4% [7]. We recently presented device physics simulations which predicted efficiencies exceeding 17%, based on experimentally observed diffusion lengths within our wires [8]. However, this model did not take into account the optical properties of a wire array device - in particular the inherently low packing fraction of wires within CVD-grown wire arrays, which might limit their ability to fully absorb incident sunlight. For this reason, we have combined a device physics model of Si wire solar cells with FDTD simulations of light absorption within wire arrays to investigate the potential photovoltaic efficiency of this cell geometry. We have found that even a sparsely packed array (14%) is expected to absorb moderate (66%) amounts of above-bandgap solar energy, yielding a simulated photovoltaic efficiency of 14.5%. Because the wire array comprises such a small volume of Si, the observed absorption represents an effective optical concentration, which enables greater operating voltages than previously predicted for Si wire array solar cells
Determinants of club head speed in PGA professional golfers
Club head speed (CHS) has been significantly correlated to golf performance, but only in amateurs. The purpose of this study therefore, was to investigate the relationship between field-based measures of strength and power with CHS in PGA professional golfers, and further, determine differences between age groups. A correlation design was used to test relationships between squat jump (SJ), seated medicine ball throw (SMBT), rotational medicine ball throw (RMBT) and CHS. Twenty participants volunteered to take part in the study (age: 31.95 +/- 8.7 years, height: 182.75 +/- 6.88cm, mass: 90.47 +/- 15.6kg). Intraclass correlation coefficients reported high reliability for performance variables (r = 0.85-0.95). Significant correlations (p 30 (n = 10; 39.7 +/- 5.5 years). Correlations to CHS for 30 also had significant correlations to CHS in SMBT (r = 0.881) and SJ (r = 0.729), but also in RMBT (r = 0.642). The results of this study suggest that SJ and SMBT have the largest contribution to CHS in PGA professional golfers. When comparing age groups, it appears that younger golfers ( 30 years) utilise more upper body strength. Results suggest that strength based leg exercises and power based chest exercises may improve CHS in professional golfers
Assessment of strength and power capacities in elite male soccer: a systematic review of test protocols used in practice and research
Strength and power represent two crucial physical qualities for the attainment of a high level of performance considering the frequency and the importance of explosive actions occurring during elite soccer match-play. Evaluation of strength and power is a multifaceted concept involving a vast array of tests and outcome variables. Nevertheless, a comprehensive and systematic search of strength and power assessment procedures in elite soccer has yet to be undertaken. The aims of this systematic review were to: (1) identify the tests and outcome variables used to assess strength and power of elite male soccer players; (2) provide normative values for the most common tests of strength and power across different playing levels; and (3) report the reliability values of these strength and power tests. A systematic review of the academic databases MEDLINE, CINAHL, SPORTDiscus, Web of Science and OVID for studies published until August 2023 was conducted, following the Preferred Reporting Items of Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies were eligible for inclusion if they: (1) were original research studies, published in a peer-reviewed journal, and written in English language; (2) had the primary aim to assess strength and/or power; (3) players were male and older than 17Â years of age (i.e., mean age of the group); and (4) their playing level was defined as "professional", "international" or "elite". Regarding strength testing, 115 studies and 29 different tests were identified. The three most frequent strength tests were the knee extensor isokinetic strength test (58 studies), the knee flexor isokinetic strength test (55 studies) and the Nordic hamstring strength test (13 studies). In terms of power testing, 127 studies with 31 different tests were included. The three most frequent power tests were the countermovement jump with hands fixed on hips (99 studies), the squat jump (48 studies) and the vertical jump with arm swing (29 studies). The wide range of different tests and outcome variables identified in this systematic review highlights the large diversity in the employed testing procedures. The establishment of a hybrid testing approach, combining standardised and widely accepted tests for establishing normative standards and enabling comparisons across different contexts, with flexible context-specific testing batteries, has the potential to maximise the impact of testing information for practitioners. In addition, the limited reporting of reliability data across studies highlights the need for practitioners to establish their own reliability measure within their specific contexts, informing the selection of certain tests and outcome variables
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