arXiv subjects

Aritra Banerjee

Publications and source records attributed to Aritra Banerjee.

At least 73 records · Page 4Linked to original sources

arXiv2018

On multi-spin classical strings with NS-NS flux

We study multi spin semiclassical strings in $AdS_3\times S^3 \times T^4$ background supported by a mixture of Neveu-Schwarz-Neveu-Schwarz (NS-NS) and Ramond-Ramond (R-R) fluxes. This `mixed flux' background has been recently proved to be classically integrable. We start with a particular rigidly spinning fundamental string in $AdS_3\times S^1$ coupled to the NS-NS flux and classify the possible profiles. We also find out how the scaling relation among the energy and angular momenta of such a string changes due to presence of these fluxes. We emphasize on pure NS-NS flux case and discuss the fate of such solutions in that limit.

hep-th↗

arXiv2018

Fast spinning strings on $ η$ deformed $ AdS_5 \times S^{5} $

In this paper, considering the correspondence between spin chains and string sigma models, we explore the rotating string solutions over $ η$ deformed $ AdS_5 \times S^{5} $ in the so called fast spinning limit. In our analysis, we focus only on the bosonic part of the full superstring action and compute the relevant limits on both $(R \times S^{3})_η $ and $(R \times S^{5})_η $ models. The resulting system reveals that in the fast spinning limit, the sigma model on $ η$ deformed $S^5$ could be $\textit{approximately}$ thought of as the continuum limit of anisotropic $ SU(3) $ Heisenberg spin chain model. We compute the energy for a certain class of spinning strings in deformed $S^5$ and we show that this energy can be mapped to that of a similar spinning string in the purely imaginary $β$ deformed background.

hep-th↗

arXiv2017

Inhomogeneous Tensionless Superstrings

We construct a novel tensionless limit of Superstring theory that realises the Inhomogeneous Super Galilean Conformal Algebra (SGCA$_I$) as the residual symmetries in the analogue of the conformal gauge, as opposed to previous constructions of the tensionless superstring, where a smaller symmetry algebra called the Homogeneous SGCA emerged as the residual gauge symmetry on the worldsheet. We obtain various features of the new tensionless theory intrinsically as well as from a systematic limit of the corresponding features of the tensile theory. We discuss why it is desirable and also natural to work with this new tensionless limit and the larger algebra.

hep-th↗

arXiv2017

Advanced Page Rank Algorithm with Semantics, In Links, Out Links and Google Analytics

In this paper we have modified the existing page ranking mechanism as an advanced Page Rank Algorithm based on Semantics Inlinks Outlinks and Google Analytics. We have used Semantics page ranking to rank pages according to the word searched and match it with the metadata of the website and provide a value of rank according to the highest priority.We have also used Google analytics to store the number of hits of a website in a particular variable and add the required percentage amount to the ranking procedure.The proposed algorithm is used to find more relevant information according to users query.So this concept is very useful to display most valuable pages on the top of the result list on the basis of user browsing behaviour which reduce the search space to a large scale.

cs.SI↗

arXiv2017

Dynamics of Airy pulse under phase modulation: Few interesting aspects

In this work we have tried to study the interesting dynamics of Airy pulse under phase modulation. We investigate the role of linear, quadratic and cubic phase modulation on Airy pulse dynamics in pure linear regime. As a specific example, we study the influence of cubic phase modulation (CPM) as a self healing effect when the propagation dynamics of a finite energy Airy pulse is perturbed under the third order dispersion (TOD). As a consequence of TOD, the pulse flips in time domain and propagates with a reverse acceleration. This unusual propagation characteristic can be restricted through CPM which counterbalance the TOD induced flipping phenomenon. With proper analytical and numerical treatment we demonstrate, how CPM not only resists the temporal flipping but helps in preserving the pulse shape under perturbation. We put special emphasis on the study of the Airy pulse at flipping point where it loses its characteristic shape and converts itself to a pure Gaussian pulse. We derive the Gaussian width analytically and demonstrate that a suitable quadratic phase modulation can focus the Airy pulse to a point and leads to a chirp-free Gaussian pulse. The present study is useful in understanding the physical insight of the unique Airy dynamic under phase modulation

physics.optics↗

arXiv2016

On circular strings in $(AdS_3 \times S^3)_{\varkappa}$

The so called one-parameter (often called $\varkappa$) deformed $AdS$ string sigma models have attracted a lot of attention lately in the study of integrability in string theory. We construct various circular string solutions in the $(AdS_3 \times S^3)_{\varkappa}$ background and describe the characteristics of such solutions qualitatively. We study the Bohr-Sommerfeld like quantization for these string states to characterise the motion. Further we find a `long' string limit of such circular strings in the $\varkappa$-deformed $AdS_3$ and find a novel dependence of the oscillation number on the energy in the next to leading order expansion.

hep-th↗

arXiv2016

Multi-spike strings in $AdS_3$ with mixed three-form fluxes

The string sigma model in $AdS_3\times S^3$ supported by mixed three-form fluxes has recently been proved to be integrable which led to a plethora of work in this background including proposals for S matrix and study of semiclassical string profiles. Motivated by this, in this paper, we present a study of `spiky' strings in this background. We analyze the string profiles in detail and also find the dispersion relation between the charges in the `long' string limit after solving the equations of motion perturbatively upto the leading order in the Neveu-Schwarz flux $b$. We find that the dispersion for 2 spikes gets corrected by the term $-\frac{b^2}{2}\log S$. We also discuss the fate of the solution in the limit of pure NS-NS flux.

hep-th↗

arXiv2016

D1 string dynamics in curved backgrounds with fluxes

We study various rotating and oscillating D-string configurations in some general backgrounds with fluxes. In particular, we look for solutions to the equations of motion of various rigidly rotating D-strings in $AdS_3$ background with mixed flux, and in the intersecting D-brane geometries. We find out relations among various conserved charges corresponding to the breathing and rotating D-string configurations.

hep-th↗

arXiv2016

Tuning of thermoelectric properties with changing Se content in Sb2Te3

Polycrystalline Sb 2 Te 3-x Se x (0.0 < x < 1.0) samples were synthesized by the solid state reaction method. The structural analysis showed that up to the maximal concentration of Se, the samples possess the Rhombohedral crystal symmetry (space group R 3 m ). Increase of Se content increases the resistivity of the samples. Variation of phonon frequencies, observed from Raman spectroscopic study, depict anomalous behaviour around x = 0.2. The sample Sb 2 Te 2.8 Se 0.2 also shows maximum Seebeck coefficient, carrier concentration and thermoelectric power factor. Nature of scattering mechanism controlling the thermopower data has been explored. The thermoelectric properties of the synthesized materials have been analyzed theoretically in the frame of Boltzmann equation approach.

cond-mat.mtrl-sci↗

arXiv2015

The effect of quenching from different temperatures on Bi 0.88 Sb 0.12 alloy

Structural, thermal, resistive and magnetic properties of melt quenched Bi 0.88 Sb 0.12 alloys are reported. The samples are heated at three different temperatures, followed by rapid quenching in liquid nitrogen. Large temperature difference between liquidus and solidus lines, led to microscopic in-homogeneity in the alloy. The effect of quenching from different temperatures in polycrystalline Bi 0.88 Sb 0.12 alloy has been studied. The parameters such as strain, unit cell volume, and resistivity are found to increase with temperature. Thermal variation of resistivity depicts non monotonic temperature dependence. The total negative susceptibility increases and band gap of semiconducting Bi 0.88 Sb 0.12 samples decreases with increasing temperature.

cond-mat.mtrl-sci↗

arXiv2015

A note on oscillating strings in $AdS_3 \times S^3$ with mixed three-form fluxes

We present a detailed study of the pulsating string solutions in AdS3 x S3 supported by both RR and NS-NS fluxes. This background has recently been proved to be integrable. We find the dispersion relation between the energy, oscillation number and other conserved charges when the NS-NS flux turned on is small. We further discuss the fate of the string solutions in pure RR and NS-NS cases.

hep-th↗

arXiv2015

Defect induced structural and thermoelectric properties of Sb2Te3 alloy

Structural and thermoelectric properties of metallic and semiconducting Sb2Te3 are reported. X-Ray diffraction and Raman spectroscopy studies reveal that semiconducting sample have higher defect density. Nature and origin of possible defects are highlighted. Semiconducting Sb2Te3 hosts larger numbers of defects, which act as scattering center and give rise to the increased value of resistivity, thermopower and power factor. Thermopower data indicates p-type nature of the synthesized samples. It is evidenced that the surface states are often mixed with the bulk state, giving rise to metallicity in Sb2Te3. Role of different scattering mechanism on the thermoelectric property of Sb2Te3 is discussed.

cond-mat.mtrl-sci↗

arXiv2015

Spiky strings in $\varkappa$-deformed $AdS$

We study rigidly rotating strings in $\varkappa$-deformed $AdS$ background. We probe this classically integrable background with `spiky' strings and analyze the string profiles in the large charge limit systematically. We also discuss the dispersion relation among the conserved charges for these solutions in long string limit.

hep-th↗

arXiv2014

Spiky strings on AdS3 x S3 with NS-NS flux

We study rigidly rotating strings in the background of AdS3 x S3 with Neveu-Schwarz (NS) fluxes. We find two interesting limiting cases corresponding to the known giant magnon and the new single spike solution of strings in the above background and write down the dispersion relations among various conserved charges. We use proper regularization to find the correct relations among them. We further study the circular and infinite spiky strings on AdS and study their properties.

hep-th↗

arXiv2014

Semiclassical Strings in Supergravity PFT

Puff Field Theory (PFT) is an example of a non-local field theory which arises from a novel embedding of D-branes in Melvin universe. We study several rotating and pulsating string solutions of the F-string equations of motion in the supergravity dual of the PFT. Further, we find a PP-wave geometry from this nonlocal spacetime by applying a Penrose limit and comment on its similarity with the maximally supersymmetric PP-wave background.

hep-th↗

arXiv2014

On the Rotating and Oscillating strings in $(AdS_3\times S^3)_{\varkappa}$

We study rigidly rotating strings in the $\varkappa$-deformed $AdS_3 \times S^3$ background. We find out two classes of solutions corresponding to the giant magnon and single spike solutions of the string rotating in two $S^2_{\varkappa}$ subspace of rotations reduced along two different isometries. We verify that the dispersion relations reduce to the well known relation in the $\varkappa\rightarrow 0$ limit. We further study some oscillating string solutions in the $S^3_{\varkappa}$ subspace.

hep-th↗

arXiv2014

Magnetoresistive property study of direct and indirect band gap thermoelectric Bi-Sb alloys

We report magnetoresistive properties of direct and indirect band gap Bismuth-Antimony (Bi-Sb) alloys. Band gap increases with magnetic field. Large positive magnetoresistance (MR) approaching to 400 % is observed. Low field MR experiences quadratic growth and at high field it follows a nearly linear behavior without sign of saturation. Carrier mobility extracted from low field MR data, depicts remarkable high value. Correlation between MR and mobility is revealed. We demonstrate that the strong nearly linear MR at high field can be well understood by classical method, co-build by Parish and Littlewood.

cond-mat.mtrl-sci↗

arXiv2013

Temperature-dependent structural property and power factor of n type thermoelectric Bi0.90Sb0.10 and Bi0.86Sb0.14 alloys

Thermal variation of structural property, linear thermal expansion coefficient, resistivity, thermopower and power factor of polycrystalline Bi1-xSbx (x=0.10, 0.14) samples are reported. Temperature-dependent powder diffraction experiments indicate that samples do not undergo any structural phase transition. Rietveld refinement technique has been used to perform detailed structural analysis. Temperature dependence of thermal expansion coefficient is found to be stronger for Bi0.90Sb0.10. Also, power factor for direct band gap Bi0.90Sb0.10 is higher as compared to that for indirect band gap Bi0.86Sb0.14. Role of electron-electron and electron-phonon scattering on resistivity, thermopower and power factor have been discussed.

cond-mat.mtrl-sci↗