14,953 research outputs found
Wigner distribution, nonclassicality and decoherence of generalized and reciprocal binomial states
There are quantum states of light that can be expressed as finite
superpositions of Fock states (FSFS). We demonstrate the nonclassicality of an
arbitrary FSFS by means of its phase space distributions such as the Wigner
function and the -function. The decoherence of the FSFS is studied by
considering the time evolution of its Wigner function in amplitude decay and
phase damping channels. As examples, we determine the nonclassicality and
decoherence of generalized and reciprocal binomial states.Comment: 18 pages, 8 Figure
Accuracy of urinary human papillomavirus testing for presence of cervical HPV: systematic review and meta-analysis
This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 3.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/3.0/.Funding: This study did not receive any fundin
Dynamic Density Response of Trapped Interacting Quantum Gases
An expression for the dynamic density response function has been obtained for
an interacting quantum gas in Random Phase Approximation (RPA) including first
order self and exchange contribution. It involves the single particle wave
functions and eigen values. The expression simplifies when diagonal elements
are considered. The diagonal elements of the imaginary part of Fourier
transformed response function is relevant in the measurement of Bragg
scattering cross-section and in several other applications.Comment: 2 pages, 0 figure, conferenc
URINARY TESTING FOR HPV Authors' reply to Vorsters and colleagues
This is the peer reviewed published version of the following article: URINARY TESTING FOR HPV Authors' reply to Vorsters and colleagues, which has been published in final form at 10.1136/bmj.g6253. This article may be used for non-commercial purposes in accordance with BMJ's Terms and Conditions for Self-Archiving.
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Dynamics of Uniform Quantum Gases, I: Density and Current Correlations
A unified approach valid for any wavenumber, frequency, and temperature is
presented for uniform ideal quantum gases allowing for a comprehensive study of
number density and particle-current density response functions. Exact
analytical expressions are obtained for spectral functions in terms of
polylogarithms. Also, particle-number and particle-current static
susceptibilities are presented which, for fugacity less than unity,
additionally involve Kummer functions. The wavenumber and temperature dependent
transverse-current static susceptibility is used to show explicitly that
current correlations are of a long range in a Bose-condensed uniform ideal gas
but for bosons above the critical temperature and for Fermi and Boltzmann gases
at all temperatures these correlations are of short range. Contact repulsive
interactions for systems of neutral quantum particles are considered within the
random-phase approximation. The expressions for particle-number and
transverse-current susceptibilities are utilized to discuss the existence or
nonexistence of superfluidity in the systems under consideration
Effects on Amorphous Silicon Photovoltaic Performance from High-temperature Annealing Pulses in Photovoltaic Thermal Hybrid Devices
There is a renewed interest in photovoltaic solar thermal (PVT) hybrid
systems, which harvest solar energy for heat and electricity. Typically, a main
focus of a PVT system is to cool the photovoltaic (PV) cells to improve the
electrical performance, however, this causes the thermal component to
under-perform compared to a solar thermal collector. The low temperature
coefficients of amorphous silicon (a-Si:H) allow for the PV cells to be
operated at higher temperatures and are a potential candidate for a more
symbiotic PVT system. The fundamental challenge of a-Si:H PV is light-induced
degradation known as the Staebler-Wronski effect (SWE). Fortunately, SWE is
reversible and the a-Si:H PV efficiency can be returned to its initial state if
the cell is annealed. Thus an opportunity exists to deposit a-Si:H directly on
the solar thermal absorber plate where the cells could reach the high
temperatures required for annealing.
In this study, this opportunity is explored experimentally. First a-Si:H PV
cells were annealed for 1 hour at 100\degreeC on a 12 hour cycle and for the
remaining time the cells were degraded at 50\degreeC in order to simulate
stagnation of a PVT system for 1 hour once a day. It was found that, when
comparing the cells after stabilization at normal 50\degreeC degradation, this
annealing sequence resulted in a 10.6% energy gain when compared to a cell that
was only degraded at 50\degreeC
Competition between antiferromagnetism and superconductivity, electron-hole doping asymmetry and "Fermi Surface" topology in cuprates
We investigate the asymmetry between electron and hole doping in a 2D Mott
insulator, and the resulting competition between antiferromagnetism (AF) and
d-wave superconductivity (SC), using variational Monte Carlo for projected wave
functions. We find that key features of the T = 0 phase diagram, such as
critical doping for SC-AF coexistence and the maximum value of the SC order
parameter, are determined by a single parameter which characterises the
topology of the "Fermi surface" at half filling defined by the bare
tight-binding parameters. Our results give insight into why AF wins for
electron doping, while SC is dominant on the hole doped side. We also suggest
using band structure engineering to control the parameter for enhancing SC.Comment: 4 pages, 4 figure
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