7,338 research outputs found
Arithmetic correlations over large finite fields
The auto-correlations of arithmetic functions, such as the von Mangoldt
function, the M\"obius function and the divisor function, are the subject of
classical problems in analytic number theory. The function field analogues of
these problems have recently been resolved in the limit of large finite field
size . However, in this limit the correlations disappear: the arithmetic
functions become uncorrelated. We compute averages of terms of lower order in
which detect correlations. Our results show that there is considerable
cancellation in the averaging and have implications for the rate at which
correlations disappear when ; in particular one cannot
expect remainder terms that are of the order of the square-root of the main
term in this context.Comment: The paper has been accepted by IMR
Multiatom Quantum Coherences in Micromasers as Fuel for Thermal and Nonthermal Machines
In this paper we address the question: To what extent is the quantum state
preparation of multiatom clusters (before they are injected into the microwave
cavity) instrumental for determining not only the kind of machine we may
operate but also the quantitative bounds of its performance? Figuratively
speaking, if the multiatom cluster is the "crude oil", the question is: Which
preparation of the cluster is the refining process that can deliver a
"gasoline" with a "specific octane"? We classify coherences or quantum
correlations among the atoms according to their ability to serve as (i) fuel
for nonthermal machines corresponding to atomic states whose coherences
displace or squeeze the cavity field, as well as cause its heating; and (ii)
fuel which is purely "combustible", i.e., corresponds to atomic states that
only allow for heat and entropy exchange with the field and can energize a
proper heat engine. We identify highly promising multiatom states for each kind
of fuel and propose viable experimental schemes for their implementation.Comment: 13 pages, 8 figure
Detection of non-Gaussian Fluctuations in a Quantum Point Contact
An experimental study of current fluctuations through a tunable transmission
barrier, a quantum point contact, are reported. We measure the probability
distribution function of transmitted charge with precision sufficient to
extract the first three cumulants. To obtain the intrinsic quantities,
corresponding to voltage-biased barrier, we employ a procedure that accounts
for the response of the external circuit and the amplifier. The third cumulant,
obtained with a high precision, is found to agree with the prediction for the
statistics of transport in the non-Poissonian regime.Comment: 4 pages, 4 figures; published versio
Observation of the rare decay B+ -> K+Ļ0Ļ0 and measurement of the quasi-two-body contributions B+ -> K*(892)+Ļ0, B+ -> f0(980)K+, and B+ -> Ļc0K+
We report an analysis of charmless hadronic decays of charged B mesons to the final state K(+) pi(0)pi(0), using a data sample of (470.9 +/- 2.8) x 10(6) B (B) over bar events collected with the BABAR detector at the Y(4S) resonance. We observe an excess of signal events, with a significance above 10 standard deviations including systematic uncertainties, and measure the branching fraction and CP asymmetry to be B(B(+) -> K(+) pi(0)pi(0)) = (16.2 +/- 1.2 +/- 1.5) x 10(-6) and A(CP)(B(+) -> K(+) pi(0)pi(0)) = -0.06 +/- 0.06 +/- 0.04, where the uncertainties are statistical and systematic, respectively. Additionally, we study the contributions of the B(+) -> K*(892)(+) pi(0), B(+) -> f(0)(980)K(+), and B(+) -> chi(c0)K(+) quasi-two-body decays. We report the world's best measurements of the branching fraction and CP asymmetry of the B(+) -> K(+) pi(0)pi(0) and B(+) -> K(+)(892)(+) pi(0) channels
Adopting Hybrid Energy Technology for Carbon Emissions Reduction in Nigeriaās Telecommunications Industry
Telecoms cell sites, powered by petrol and diesel generators, have high carbon
footprints and contribute increasingly to global warming, and thereby climate change. Utilizing
primary data from telecom cell sites of a major operator in Nigeria, this study empirically
determines the firmās CO2 emissions and considers how hybrid energy technology (HET) could be
adopted to reduce the industryās carbon footprint. Data of fuel utilization in power generation are
applied to compute CO2 emissions. Towards reducing the firmās and industryāsemissions, hybrid
energy technology options for incorporating solarin the energy mix are considered. Hybrid energy
technologies optimize existing hydrocarbon generating plants with photovoltaic panels and storage
batteries to provide minimum capacities for powering the electronic devises.Results show that
HET opportunities exist for most telecom firmsā cell sites given Nigeriaās geographical advantage
to access sunlight. In addition, through the adoption of hybrid energy, average daily fuel usage is
reduced by 50% (apart from periods of peak demand and weather disruptions). If adopted by the
major telecoms operators, as recommended, greenhouse gas emissions level in the industry will
reduce significantly.A few notable challenges are highlighted in the paper. However, job creation
in the renewable energy industry is a notable advantage of transforming power generation in the
telecommunications industry
Distinct subpopulations of enteric neuronal progenitors defined by time of development, sympathoadrenal lineage markers and Mash-1-dependence
Enteric and sympathetic neurons have previously been proposed to be lineally related. We present independent lines of evidence that suggest that enteric neurons arise from at least two lineages, only one of which expresses markers in common with sympathoadrenal cells. In the rat, sympathoadrenal markers are expressed, in the same order as in sympathetic neurons, by a subset of enteric neuronal precursors, which also transiently express tyrosine hydroxylase. If this precursor pool is eliminated in vitro by complement-mediated lysis, enteric neurons continue to develop; however, none of these are serotonergic. In the mouse, the Mash-1ā/ā mutation, which eliminates sympathetic neurons, also prevents the development of enteric serotonergic neurons. Other enteric neuronal populations, however, including those that contain calcitonin gene related peptide are present. Enteric tyrosine hydroxylase-containing cells co-express Mash-1 and are eliminated by the Mash-1ā/ā mutation, consistent with the idea that in the mouse, as in the rat, these precursors generate serotonergic neurons. Serotonergic neurons are generated early in development, while calcitonin gene related peptide-containing enteric neurons are generated much later. These data suggest that enteric neurons are derived from at least two progenitor lineages. One transiently expresses sympathoadrenal markers, is Mash-1-dependent, and generates early-born enteric neurons, some of which are serotonergic. The other is Mash-1-independent, does not express sympathoadrenal markers, and generates late-born enteric neurons, some of which contain calcitonin gene related peptide
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