Modulated bimaximal neutrino mixing

The present article is an endeavor to look into some fruitful frameworks based on "Bi-maximal" neutrino mixing, from a model independent stand. The possibilities involving the correction or attenuation of the original BM mixing matrix, followed by GUT-inspired charged lepton correction are invoked. The "symmetry-basis" thus constructed, accentuates some interesting facets such as: a modified QLC relation, $\theta_{12}+\theta_{c}\approx\frac{\pi}{4}-\theta_{13}\cos(n\pi-\delta_{CP})$, a possible link up between neutrino and charged lepton sectors, $\theta_{13}^{\nu}=\theta_{12}^{l}\sim\mathcal{O}(\theta_{C})$ or that between neutrinos and quarks, $\theta_{13}^{\nu}=\theta_{C}$. The study vindicates the relevance of the Bi-maximal mixing as a first approximation

Generating nonzero θ13\theta_{13} without breaking the 22-33 symmetry of neutrino mass matrix

The prediction of vanishing reactor angle was thought to be a signature of $2$-$3$ symmetry of neutrino mass matrix. But the present study addresses certain interesting facts related with $2$-$3$ symmetry which are not addressed so far. The investigation highlights that $\theta_{13}=0$, corresponds to a very special case in association with $2$-$3$ symmetry and to engender a non-zero $\theta_{13}$, the breakdown of $2$-$3$ symmetry is not essential

The mixing angle as a function of neutrino mass ratio

In the quark sector, we experience a correlation between the mixing angles and the mass ratios. A partial realization of the similar tie-up in the neutrino sector helps to constrain the parametrization of masses and mixing, and hints for a predictive framework. We derive five hierarchy dependent textures of neutrino mass matrix with minimum number of parameters ($\leq\,4$), following a model-independent strategy

Bi-Large neutrino mixing with charged lepton correction

The usual Bi-Maximal (BM) neutrino mixing faces an inherent problem in lowering the solar mixing angle below $\tan^{2}\theta_{12}=0.50$ when charged lepton correction is taken. This minimum $\theta_{12}$ is achievable only if CP violation is absent. We start with a new model which incorporates a new idea of mixing developed recently, called Bi-Large (BL) mixing, similar to BM mixing execpt that the former chooses rather $\theta_{13}$ as Cabibbo angle $(\theta_c)$ than zero. We apply this mixing in the neutrino sector, followed by a charged lepton correction with the CKM type matrix $U_{l}$. This model marks a prediction on $\theta_{23}$ to lie within the first octant. The CP violating phase $\delta_{CP}$ dictates the prediction of all the three mixing angles. A proper choice of $\delta_{CP}$ leads to the predictions of all the three mixing angles including $\theta_{12}$, to align very precisely with the experimental bestfits. This close agreement thus hoists Bi-Large mixing as an important and promising mixing scheme, in contrast to BM or TBM mixing as a first approximation. A formal derivation of BL mixing from discrete symmetry will be an important investigation in neutrino physics.Comment: 8 pages, 7 figure

Expansion of UPMNSU_{PMNS} and Neutrino mass matrix MνM_{\nu} in terms of sinθ13sin\theta_{13} for Inverted Hierarchical case

The recent observational data supports the deviation from Tri-bimaximal (TBM) mixings. Different neutrino mass models suggest the interdependency among the observational parameters involving the mixing angles. On phenomenological ground we try to construct the PMNS matrix $U_{PMNS}$ with certain analytic structure satisfying the unitary condition, in terms of a single observational parameter $sin\theta_{13}$. We hypothesise the three neutrino masses $m_{i}$ as functions of $sin\theta_{13}$ and then construct the neutrino mass matrix $M_{\nu}$. We assume the convergence of the model to TBM mixing when $\theta_{13}$ is taken zero. This mass matrix so far obtained can be employed for various applications including the estimation of matter-antimatter asymmetry of the Universe.Comment: 9 pages, 5 figure

A new method of parametrisation of neutrino mass matrix through breaking of μ−τ\mu-\tau symmetry: Normal hierarchy

In the first part of the present work the $\mu-\tau$ symmetry of the neutrino mass matrix is perturbed at its minimal level in order to produce deviation from Tri-bimaximal mixing (TBM), which includes nonzero value of reactor angle $\theta_{13}$ and maximal condition of $\tan^{2}\theta_{23}=1$. The parametrisation of neutrino mass matrix which describes Normal hierarchy (NH), has been addressed with minimum number of independent parameters, out of which two parameters $\eta$ and $\alpha$ take care of $\theta_{12}$ and $\theta_{13}$ respectively without any interference with mass eigenvalues. In the second part the deviation from maximal condition $\tan^{2}\theta_{23}=1$, along with the nonzero value of $\theta_{13}$, has been implemented with the introduction of a perturbing matrix which breaks the $\mu-\tau$ symmetric mass matrix. The model is found to be flexible enough to adjust itself with the changing precise experimental results. The method is also applicable for inverted hierarchy and quasi-degenerate cases.Comment: 19 pages, 14 figure

Usage Analysis of Mobile Devices

Mobile devices have evolved from just communication devices into an indispensable part of people's lives in form of smartphones, tablets and smart watches. Devices are now more personal than ever and carry more information about a person than any other. Extracting user behaviour is rather difficult and time-consuming as most of the work previously has been manual or requires feature extraction. In this paper, a novel approach of user behavior detection is proposed with Deep Learning Network (DNN). Initial approach was to use recurrent neural network (RNN) along with LSTM for completely unsupervised analysis of mobile devices. Next approach is to extract features by using Long Short Term Memory (LSTM) to understand the user behaviour, which are then fed into the Convolution Neural Network (CNN). This work mainly concentrates on detection of user behaviour and anomaly detection for usage analysis of mobile devices. Both the approaches are compared against some baseline methods. Experiments are conducted on the publicly available dataset to show that these methods can successfully capture the user behaviors.Comment: 7 page

Study of spin pumping in Co thin film vis-a-vis seed and capping layer using ferromagnetic resonance spectroscopy

We investigated the dependence of the seed [Ta/Pt, Ta/Au] and capping [Pt/Ta, Au/Ta] layers on spin pumping effect in the ferromagnetic 3 nm thick Co thin film using ferromagnetic resonance spectroscopy. The data is fitted with Kittel equation to evaluate damping constant and g-factor. A strong dependence of seed and capping layers on spin pumping has been discussed. The value of damping constant {alpha} is found to be relatively large i.e. 0.0326 for the Ta{3}/Pt{3}/Co{3}/Pt{3}/Ta{3} {nm} multi-layer structure, while it is 0.0104 for Ta{3}/Co{3}/Ta{3} {nm}. Increase in {alpha} is observed due to Pt layer that works as a good sink for spins due to high spin orbit coupling. In addition, we measured the effective spin conductance = 2.0e18 m-2 for the trilayer structure Pt{3}/Co{3}/Pt{3} {nm} as a result of the enhancement in {alpha} relative to its bulk value. We observed that the evaluated g-factor decreases as effective demagnetizing magnetic field increases in all the studied samples. The azimuthal dependence of magnetic resonance field and line width showed relatively high anisotropy in the trilayer Ta{3}/Co{3}/Ta{3} {nm} structure.Comment: 16 pages, four figure

Exchange bias in Fe/Ir20Mn80 bilayers: Role of spin-glass like interface and bulk antiferromagnet spins

We have performed magnetic measurements like temperature (T), cooling field (HFC) dependence of exchange bias (EB) and training effect to investigate the magnetic nature of the interface of the Fe/Ir20Mn80 systems. Thin film bilayer samples of different thicknesses of Ir20Mn80 have been prepared by dc magnetron sputtering at room temperature. The variation of exchange bias field (HEB) with the increase in thickness of Ir20Mn80 predicts the antiferromagnet (AFM) bulk spins contribution to EB. Exponential decay of HEB and coercive field (HC) with temperature reveals the presence of spin glass (SG) like interface. Also, the decrease of HEB with increasing HFC confirms the SG like frustration at the interface. Further, the fitting of training effect experimental data envisages the presence of frozen and rotatable spins at the magnetically frustrated interface of these EB systems

Skyrmion Racetrack memory with an antidot

Skyrmion racetrack memory has a lots of potential in future non-volatile solid state devices. In general such devices require current to nucleate skyrmions via spin transfer torque (STT) effect. Further the current is also required to drive the skyrmions in the nanowire device. However the current applied during nucleation of successive skyrmions may have unwanted perturbation \emph{viz.} Joule heating and skyrmion Hall effect, on the propagation of previously generated skyrmions. Therefore new methodology is required to decouple the generation and propagation of skyrmions. Here we present a novel route via micromagnetic simulation for generation of skyrmions from triangular antidot structure in a ferromagnetic nanotrack using local oersted field. Antidots are holes in a magnetic nanoelement. Controlled skyrmion injection can be achieved by tuning the dimensions of the antidots that are placed at either end of the nanotrack. Multiple skyrmions can be simultaneously generated by incorporating more number of antidots. Here we propose a novel design to realise skyrmionic racetrcak memory where one can individually generate and manipulate the skyrmions within the nanotrack