Anharmonic quantum contribution to vibrational dephasing

Based on a quantum Langevin equation and its corresponding Hamiltonian within a c-number formalism we calculate the vibrational dephasing rate of a cubic oscillator. It is shown that leading order quantum correction due to anharmonicity of the potential makes a significant contribution to the rate and the frequency shift. We compare our theoretical estimates with those obtained from experiments for small diatomics $N_2$, $O_2$ and $CO$.Comment: 21 pages, 1 figure and 1 tabl

Origin, heterogeneity, and interconversion of noncanonical bistable switches from the positive feedback loops under dual signaling

Summary Designing new functional motifs with unique properties is an important objective in the realm of synthetic biology. We uncover emergent properties of positive feedback loops (PFLs) under dual input signaling using pseudo potential energy-based high-throughput bifurcation analysis. We show that under dual signaling a single PFL generates a variety of noncanonical bistable switches, with one or more bistable regions, due to fusion of multiple canonical bistable switches. Regulatory signs of the dual signaling must be coherent for mutual inhibition loop and incoherent for mutual activation loop of the PFL. Occurrence probabilities show that some of the noncanonical switches, such as isola and mushroom, are highly recurrent under random parameterization. Phase diagrams of the noncanonical switches reveal that feedback strengths of the PFL control the transition from one switch to another. Our calculations decipher the design principles of noncanonical bistable switches that originate from synthetically feasible simple PFL motifs under dual signaling

Protocol for potential energy-based bifurcation analysis, parameter searching, and phase diagram analysis of noncanonical bistable switches

We have explored the design principles of noncanonical bistable switches using high-throughput bifurcation analysis of positive feedback loops under dual signaling. Here, we present a protocol to carry out bifurcation analysis using pseudo-potential energy of the dynamical system. We also describe steps to perform automated parameter searching for canonical and noncanonical switches and multi-parameter phase diagram analysis of these switches. For complete details on the use and execution of this protocol, please refer to Das et al.

Half unit cell shift defect induced helical states in Fe-based chalcogenide superconductors

Recent scanning tunneling spectroscopy along crystalline domain-walls associated with a half unit cell shift have revealed sub-gap density of states that are expected to arise from helical Majorana modes. Such propagating Majorana modes have been proposed to exist on the surface state of topological materials similar to FeTe$_{\text{1-x}}$Se$_\text{x}$ (FTS) along line defects where the superconducting order parameter (OP) is phase shifted by $\pi$. Here we show that such a $\pi$ shift in theOP across the half unit-cell shift domain-wall can occur in quite conventional tight-binding models of superconducting FTS as a result of the $s_{\pm}$ pairing symmetry across $\Gamma$ and M pockets of FTS. The resultant inter-pocket transmission between $\Gamma$ and M pockets is found to be typically larger than the intra-pocket transmissions. We confirm these conclusions with a calculation based on the Bogoliubov-de-Gennes (BdG) formalism which shows that a $\pi$-shift across the domain-wall is favored for a large range of model parameters for FTS. We discuss parameter regimes where this mechanism might explain the STS experiments as well as propose to test this explanation by searching for evidence of large inter-pocket scattering.Comment: 8 pages, 8 figure

Electrical conductive properties of some composites of gum arabic biopolymer and magnetite nanoparticles

DC electrical conductive properties of some composites of gum arabic biopolymer (host) and magnetite nanoparticles (guest) synthesized in different weight percentages have been studied as a function of temperature and applied bias voltage to explore the effect of the guest on the electrical conduction of the host. Two types of trap distributions (single discrete and exponential) have been found in these composites. The observed results show that the conductivity of the composites increases with increasing guest content along with a decrease in activation energy. Percolation theory has been employed for the analysis of the room temperature electrical conductivity enhancement with the variation of guest content. The activation energy and the pre-exponential factor values estimated following Arrhenius relation satisfies the compensation law

FogGIS: Fog Computing for Geospatial Big Data Analytics

Cloud Geographic Information Systems (GIS) has emerged as a tool for analysis, processing and transmission of geospatial data. The Fog computing is a paradigm where Fog devices help to increase throughput and reduce latency at the edge of the client. This paper developed a Fog-based framework named Fog GIS for mining analytics from geospatial data. We built a prototype using Intel Edison, an embedded microprocessor. We validated the FogGIS by doing preliminary analysis. including compression, and overlay analysis. Results showed that Fog computing hold a great promise for analysis of geospatial data. We used several open source compression techniques for reducing the transmission to the cloud.Comment: 6 pages, 4 figures, 1 table, 3rd IEEE Uttar Pradesh Section International Conference on Electrical, Computer and Electronics (09-11 December, 2016) Indian Institute of Technology (Banaras Hindu University) Varanasi, Indi