14,600 research outputs found
Fidelity susceptibility and general quench near an anisotropic quantum critical point
We study the scaling behavior of fidelity susceptibility density at or close to an anisotropic quantum critical point characterized by two
different correlation length exponents and along
parallel and perpendicular spatial directions, respectively. Our studies show
that the response of the system due to a small change in the Hamiltonian near
an anisotropic quantum critical point is different from that seen near an
isotropic quantum critical point. In particular, for a finite system with
linear dimension () in the parallel (perpendicular)
directions, the maximum value of is found to increases in a
power-law fashion with for small , with an exponent depending
on both and and eventually crosses over to a scaling
with for . We
also propose scaling relations of heat density and defect density generated
following a quench starting from an anisotropic quantum critical point and
connect them to a generalized fidelity susceptibility. These predictions are
verified exactly both analytically and numerically taking the example of a
Hamiltonian showing a semi-Dirac band-crossing point.Comment: 6 pages, 6 pigure
Practice of wastewater irrigation and its impacts on human health and environment: a state of the art
The practice of wastewater irrigation lessens the pressure on the aquatic environment by minimizing the use of freshwater resources. However, this may lead to significant damage to the human health and environments. Recycled wastewater possesses a substantial amount of nutrients that act as fertilizers for crops and facilitate the metabolic action of microorganisms. The major advantages of wastewater irrigation are increased agricultural production, nutrient recycling, reduced stress on freshwater, economical support and provision of livelihoods for farmers. However, several harmful impacts of wastewater irrigation are also prominent due to inappropriate wastewater management and irrigation practices. These include severe hazards to farmer’s health, contamination of agricultural land and crops with toxic metals, chemical compounds, salts and microbial pathogens. In addition, long-term irrigation using wastewater can significantly affect the groundwater through leakage of salty and toxic metal-rich wastewater making it unfit for human consumption. Wastewater irrigation may also alter the physicochemical properties and microbiota of soil, which in turn can disturb land fertility and crop productivity. Several factors need to be considered while using treated or partially treated wastewater for irrigation such as diversity and type of pollutants, available nutrients, pathogenic microorganisms and soil salinity. In this review paper, we assess the impact of wastewater irrigation on humans as well as on the environment based on available case studies globally, outline current use of wastewater for irrigation of agricultural crops such as cereals, vegetables, fodder crops, including agroforestry and discuss suitable management practices of wastewater reuse for irrigation
Switching of the topologically trivial and non-trivial quantum phase transitions in compressed 1T-TiTe2: Experiments and Theory
We report the structural, vibrational and electrical transport properties up
to 16 GPa of the 1T-TiTe2, a prominent layered 2D system, which is predicted to
show a series of topologically trivial - nontrivial transitions under
hydrostatic compression. We clearly show signatures of two iso-structural
transition at 2 GPa and 4 GPa obtained from the minima in c/a ratio concomitant
with the phonon linewidth anomalies of Eg and A1g modes at around the same
pressures, providing strong indication of unusual electron-phonon coupling
associated to these transitions. Resistivity presents nonlinear behavior over
similar pressure ranges providing a strong indication of the electronic origin
of these pressure driven isostructural transitions. Our data thus provide clear
evidences of topological changes at A and L point of the Brillouin zone
predicted to be present in the compressed 1T-TiTe2. Between 4 GPa and 8 GPa,
the c/a ratio shows a plateau suggesting a transformation from an anisotropic
2D layer to a quasi 3D crystal network. First principles calculations suggest
that the 2D to quasi 3D evolution without any structural phase transitions is
mainly due to the increased interlayer Te-Te interactions (bridging) via the
charge density overlap. In addition to the pressure dependent isostructural
phase transitions, our data also evidences the occurrence of a first order
structural phase transition from the trigonal (P-3m1) phase at higher
pressures. We estimate the start of this structural phase transition to be 8
GPa and the symmetric of the new high-pressure phase to be monoclinic (C2/m).Comment: 22 pages, 11 Figures, 2 Table
Substrate Inhibition Growth Kinetics for Cutinase Producing Pseudomonas cepacia Using Tomato-peel Extracted Cutin
Using tomato-peel extracted cutin, an economically viable substrate, cutinase production by Pseudomonas cepacia was studied at different initial substrate concentrations (2–20 g L–1). The highest volumetric enzyme activity was observed at 10 g L–1 of cutin, which was inhibited at further higher concentrations. Various 3-, 4- and 5- parametric Monod-variant models were chosen to analyze the inhibition kinetics. The model parameters as well as goodness of fit were estimated using non-linear regression analysis. The
4- parameter Webb model was the best-fit model (R2 = 0.933), followed by the 3-parameter Andrews model (R2 = 0.92). Parameter sensitivity analysis revealed that the maximum specific growth rate was the most sensitive parameter for both the models, and the
Webb constant was the least sensitive. Finally, based on a strong evidence ratio 190.65 from Akaike’s information content criteria analysis as well as extra sum of square F test (P > 0.05), it was found that 3-parameter Andrews model gave the best fit
How did the discussion go: Discourse act classification in social media conversations
We propose a novel attention based hierarchical LSTM model to classify
discourse act sequences in social media conversations, aimed at mining data
from online discussion using textual meanings beyond sentence level. The very
uniqueness of the task is the complete categorization of possible pragmatic
roles in informal textual discussions, contrary to extraction of
question-answers, stance detection or sarcasm identification which are very
much role specific tasks. Early attempt was made on a Reddit discussion
dataset. We train our model on the same data, and present test results on two
different datasets, one from Reddit and one from Facebook. Our proposed model
outperformed the previous one in terms of domain independence; without using
platform-dependent structural features, our hierarchical LSTM with word
relevance attention mechanism achieved F1-scores of 71\% and 66\% respectively
to predict discourse roles of comments in Reddit and Facebook discussions.
Efficiency of recurrent and convolutional architectures in order to learn
discursive representation on the same task has been presented and analyzed,
with different word and comment embedding schemes. Our attention mechanism
enables us to inquire into relevance ordering of text segments according to
their roles in discourse. We present a human annotator experiment to unveil
important observations about modeling and data annotation. Equipped with our
text-based discourse identification model, we inquire into how heterogeneous
non-textual features like location, time, leaning of information etc. play
their roles in charaterizing online discussions on Facebook
Quantum Discord in a spin-1/2 transverse XY Chain Following a Quench
We report a study on the zero-temperature quantum discord as a measure of
two-spin correlation of a transverse XY spin chain following a quench across a
quantum critical point and investigate the behavior of mutual information,
classical correlations and hence of discord in the final state as a function of
the rate of quenching. We show that though discord vanishes in the limit of
very slow as well as very fast quenching, it exhibits a peak for an
intermediate value of the quenching rate. We show that though discord and also
the mutual information exhibit a similar behavior with respect to the quenching
rate to that of concurrence or negativity following an identical quenching,
there are quantitative differences. Our studies indicate that like concurrence,
discord also exhibits a power law scaling with the rate of quenching in the
limit of slow quenching though it may not be expressible in a closed power law
form. We also explore the behavior of discord on quenching linearly across a
quantum multicritical point (MCP) and observe a scaling similar to that of the
defect density.Comment: 6 pages, 5 figure
Quantum Poincare Recurrences for Hydrogen Atom in a Microwave Field
We study the time dependence of the ionization probability of Rydberg atoms
driven by a microwave field, both in classical and in quantum mechanics. The
quantum survival probability follows the classical one up to the Heisenberg
time and then decays algebraically as P(t) ~ 1/t. This decay law derives from
the exponentially long times required to escape from some region of the phase
space, due to tunneling and localization effects. We also provide parameter
values which should allow to observe such decay in laboratory experiments.Comment: revtex, 4 pages, 4 figure
Intermediate scale as a source of lepton flavor violation in SUSY SO(10)
In supersymmetric SO(10) grand unified models, we examine the lepton flavor
violation process from having the SU(2)U(1) gauge symmetry broken at an intermediate scale below the
SO(10) grand unification scale . Even in the case that supersymmetry is
broken by universal soft terms introduced at the scale , we find
significant rates for with GeV or
less. These rates are further enhanced if the universal soft terms appear at a
scale greater than .Comment: 12 pages (Latex), 3 PS Figures (uuencoded, epsf.tex), small addition
to discussion in the text, as to appear in Phys. Rev. D Rapid Communication
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