904 research outputs found
RETURNS TO SCALE AND SIZE IN AGRICULTURAL ECONOMICS: REPLY
Research Methods/ Statistical Methods,
Tensor network simulation of multi-environmental open quantum dynamics via machine learning and entanglement renormalisation
The simulation of open quantum dynamics is a critical tool for understanding how the non-classical properties of matter might be functionalised in future devices. However, unlocking the enormous potential of molecular quantum processes is highly challenging due to the very strong and non-Markovian coupling of âenvironmentalâ molecular vibrations to the electronic âsystemâ degrees of freedom. Here, we present an advanced but general computational strategy that allows tensor network methods to effectively compute the non-perturbative, real-time dynamics of exponentially large vibronic wave functions of real molecules. We demonstrate how ab initio modelling, machine learning and entanglement analysis can enable simulations which provide real-time insight and direct visualisation of dissipative photophysics, and illustrate this with an example based on the ultrafast process known as singlet fission
An experiment for the measurement of the bound-beta decay of the free neutron
The hyperfine-state population of hydrogen after the bound-beta decay of the
neutron directly yields the neutrino left-handedness or a possible right-handed
admixture and possible small scalar and tensor contributions to the weak force.
Using the through-going beam tube of a high-flux reactor, a background free
hydrogen rate of ca. 3 s can be obtained. The detection of the neutral
hydrogen atoms and the analysis of the hyperfine states is accomplished by Lamb
shift source type quenching and subsequent ionization. The constraints on the
neutrino helicity and the scalar and tensor coupling constants of weak
interaction can be improved by a factor of ten.Comment: 9 pages, 5 figures. Submitted to EPJ
The QUEST large area CCD camera
We have designed, constructed, and put into operation a very large area CCD camera that covers the field of view of the 1.2 m Samuel Oschin Schmidt Telescope at the Palomar Observatory. The camera consists of 112 CCDs arranged in a mosaic of four rows with 28 CCDs each. The CCDs are 600 x 2400 pixel Sarnoff thinned, back-illuminated devices with 13 ”m x 13 ”m pixels. The camera covers an area of 4.6° x 3.6° on the sky with an active area of 9.6 deg_2. This camera has been installed at the prime focus of the telescope and commissioned, and scientific-quality observations on the Palomar-QUEST Variability Sky Survey were started in 2003 September. The design considerations, construction features, and performance parameters of this camera are described in this paper
Homogenous Meets Heterogenous and Electro-Catalysis: Iron-Nitrogen Molecular Complexes within Carbon Materials for Catalytic Applications
The Low-Redshift Quasar-Quasar Correlation Function from an Extragalactic Halpha Emission-Line Survey to z=0.4
We study the large-scale spatial distribution of low-redshift quasars and
Seyfert~1 galaxies using a sample of 106 luminous emission-line objects
() selected by their H emission lines in a
far-red objective prism survey (). Of the 106 objects, 25 were
previously known AGN (Veron-Cetty and Veron 2000), and follow-up spectroscopy
for an additional 53 objects (including all object pairs with separation r <
20 \hmpc) confirmed 48 AGN and 5 narrow emission-line galaxies (NELGs). The
calculated amplitude of the spatial two-point correlation function for the
emission-line sample is A = 0.4 \cdot \bar{\xi}(r < 20 \hmpc) \cdot 20^{1.8} =
142 \pm 53. Eliminating the confirmed NELGs from the sample we obtain the AGN
clustering amplitude . Using Monte Carlo simulations we reject
the hypothesis that the observed pair counts were drawn from a random
distribution at the 99.97% and 98.6% confidence levels for the entire sample
and the AGN subset respectively. We measure a decrease in the quasar clustering
amplitude by a factor of between and ,
and present the coordinates, redshifts, and follow-up spectroscopy for the 15
previously unknown AGN and 4 luminous NELGs that contribute to the clustering
signal.Comment: ApJ, in press, Vol 548, added follow-up spectroscop
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