2,422 research outputs found
Evolution of Goldstone mode in binary condensate mixtures
We show that the third Goldstone mode in the two-species condensate mixtures,
which emerges at phase-separation, gets hardened when the confining potentials
have separated trap centers. The {\em sandwich} type condensate density
profiles, in this case, acquire a {\em side-by-side} density profile
configuration. We use Hartree-Fock-Bogoliubov theory with Popov approximation
to examine the mode evolution and density profiles for these phase transitions
at .Comment: 5 pages, 2 figures. Some part of the theory is common to
arXiv:1307.5716 and arXiv:1405:6459, so that the article is self-contained
for the benefit of the reader
Distribution of mosquito larvae in rice field habitats: A spatial scale analysis in semi-field condition
The distribution of the mosquito larvae in the breeding habitats varies at the spatial scale depending on the availability of the resources and the predators. This proposition was assessed through the observation of the spatial distribution of Culex larvae (Culex tritaeniorhynchus) in artificially constructed rice field habitats. Using a binomial generalized linear model with logit link, the disparity in the abundance of the larvae was evaluated to justify the effects of light (light vs shade), vertical (surface vs bottom), and horizontal (wall vs center) distribution as explanatory variables. Under light availability, the spatial occupancy of the mosquito larvae was higher in the center than in the walls of the mesocosms. However, the larval orientation was higher on the surface than at the bottom of the mesocosms in all instances. In comparison to open spaces, the larval aggregation was higher in the presence of the floating vegetations like Azolla and Lemna, indicating that the habitat heterogeneity of the mesocosms influenced the distribution of the mosquito larvae in the available spaces. A reduction in the larval aggregation pattern in the spaces was observed in the presence of the predator (Anisops sp.) reflecting the possible evasion tactics of the mosquito larvae. The observations suggest that the mosquito larvae may utilize the vegetation in the rice field habitats quite effectively and occupy empty spaces of predators. The results may be considered as a prototype of the prospective localization of the mosquito larvae in the rice fields and help to frame the strategies of spraying the biopesticides to achieve optimal efficacy in mosquito regulation
New constraints on R-parity violation from proton stability
We derive stringent upper bounds on all the -type
combinations from the consideration of proton stability, where
are baryon-number-violating trilinear couplings and
are lepton-number-violating bilinear mass parameters in a R-parity-violating
supersymmetric theory.Comment: 4 pages, Latex, uses axodraw.sty (in the revised version all
combinations of the form have been constrained, using
one-loop graphs) To appear in Phys. Lett.
A novel and low-cost instrument for color identification of natural fibres
A new instrument has been developed to find out the color of natural fibres like jute and mesta using the light reflectance method and electronic light sensors. The system has been used to measure the color range of natural fibres very effectively and is also found very economical
Exergy Analysis of a Vapor Absorption Refrigeration System Using Carbon Dioxide as Refrigerant
Vapor absorption refrigeration systems can be an alternative to vapor compression systems in many applications as they can operate on a low-grade heat source and are environment friendly. Widely used refrigerants such as CFCs and HFCs cause significant global warming. Natural refrigerants can be used instead of them, among which carbon dioxide is promising. Its inherent safety, ability to withstand high pressure and high heat transfer coefficient coupled with easy availability make it a likely choice for refrigerant. [Bmim][PF6] is a room temperature ionic liquid (RTIL) composed of a large organic cation and an inorganic anion. Its properties such as non-toxicity, stability over a wide temperature range and ability to dissolve gases like carbon dioxide, make it a suitable absorbent for a vapor absorption refrigeration system. In this paper, an absorption chiller utilising the CO2-[bmim][PF6] working pair and consisting of a generator, condenser, evaporator and absorber has been proposed. A thermodynamic model was set up using the Redlich-Kwong cubic equations of state to predict the behavior of the refrigerant and absorbent pair at different points in the system. A MATLAB code was used to obtain the values of enthalpy and entropy at selected points in the system. The exergy destruction in each component and exergetic coefficient of performance (ECOP) of the system were calculated by performing an exergy analysis based on the second law of thermodynamics. The effect of every component on the ECOP was examined by calculating the amount of exergy destruction in each of them. The exergetic coefficient of performance was calculated for five generator temperatures in the range of 60-100⁰C for an evaporator temperature of 10⁰C and was found to be in the range of 0.02-0.2. Such a chiller can be employed for refrigeration purposes, such as in the storage of food items
FORTRESS: FORTRAN programs for solving coupled Gross-Pitaevskii equations for spin-orbit coupled spin-1 Bose-Einstein condensate
Here, we present simple and efficient numerical scheme to study static and
dynamic properties of spin-1 Bose-Einstein condensates (BECs) with spin-orbit
(SO) coupling by solving three coupled Gross-Pitaevskii equations (CGPEs) in
three-, quasi-two and quasi-one dimensional systems. We provide a set of three
codes developed in FORTRAN 90/95 programming language with user defined '{\em
option}' of imaginary and real-time propagation. We present the numerical
results for energy, chemical potentials, and component densities for the ground
state and compare with the available results from the literature. The results
are presented for both the ferromagnetic and antiferromagnetic spin-1 BECs with
and without SO coupling. To improve the computational speed, all the codes have
the option of OpenMP parallelization. We have also presented the results for
speedup and efficiency of OpenMP parallelization for the three codes with both
imaginary and real-time propagation
Quantum phases and spectrum of collective modes in a spin-1 BEC with spin-orbital-angular-momentum coupling
Motivated by the recent experiments [Chen et al., Phys. Rev. Lett 121, 113204
(2018), Chen et al., Phys. Rev. Lett. 121, 250401 (2018)], we investigate the
low-lying excitation spectrum of the ground-state phases of
spin-orbital-angular-momentum-coupled (SOAM-coupled) spin-1 condensates.At
vanishing detuning, a ferromagnetic SOAM-coupled spin-1 BEC can have two
ground-state phases, namely coreless and polar-core vortex states, whereas an
antiferromagnetic BEC supports only polar-core vortex solution. The angular
momentum per particle, longitudinal magnetization, and excitation frequencies
display discontinuities across the phase boundary between the coreless vortex
and polar-core vortex phases. The low-lying excitation spectrum evaluated by
solving the Bogoliubov-de-Gennes equations is marked by avoided crossings and
hence the hybridization of the spin and density channels. The spectrum is
further confirmed by the dynamical evolution of the ground state subjected to a
perturbation suitable to excite a density or a spin mode and a variational
analysis for the density-breathing mode
Optimization in Knowledge-Intensive Crowdsourcing
We present SmartCrowd, a framework for optimizing collaborative
knowledge-intensive crowdsourcing. SmartCrowd distinguishes itself by
accounting for human factors in the process of assigning tasks to workers.
Human factors designate workers' expertise in different skills, their expected
minimum wage, and their availability. In SmartCrowd, we formulate task
assignment as an optimization problem, and rely on pre-indexing workers and
maintaining the indexes adaptively, in such a way that the task assignment
process gets optimized both qualitatively, and computation time-wise. We
present rigorous theoretical analyses of the optimization problem and propose
optimal and approximation algorithms. We finally perform extensive performance
and quality experiments using real and synthetic data to demonstrate that
adaptive indexing in SmartCrowd is necessary to achieve efficient high quality
task assignment.Comment: 12 page
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