Massive Scattering Amplitudes in Six Dimensions

We show that a natural spinor-helicity formalism that can describe massive scattering amplitudes exists in $D=6$ dimensions. This is arranged by having helicity spinors carry an index in the Dirac spinor {\bf 4} of the massive little group, $SO(5) \sim Sp(4)$. In the high energy limit, two separate kinds of massless helicity spinors emerge as required for consistency with arXiv:0902.0981, with indices in the two $SU(2)$'s of the massless little group $SO(4)$. The tensors of ${\bf 4}$ lead to particles with arbitrary spin, and using these and demanding consistent factorization, we can fix $3-$ and $4-$point tree amplitudes of arbitrary masses and spins: we provide examples. We discuss the high energy limit of scattering amplitudes and the Higgs mechanism in this language, and make some preliminary observations about massive BCFW recursion.Comment: 37 pages; v2: minor improvements, JHEP versio

Dynamics and Charge Fluctuations in Large-q Sachdev-Ye-Kitaev Lattices

It is known that the large-$q$ complex Sachdev-Ye-Kitaev (SYK) dot thermalizes instantaneously under rather general dynamical protocols. We consider a lattice of such dots coupled together, allowing for $r/2$ body hopping of particles between nearest neighbors. We develop a rather general analytical framework to study the dynamics to leading order in $1/q$ on such a lattice, allowing for arbitrary time dependent couplings, hence general dynamical protocols. We find that the physics of the diffusive case $r>2$ is effectively the same as the kinetic case $r=2$, assuming $r=\mathcal{O}(q^0)$. Remarkably, we find that the local charge densities $\mathcal{Q}_i$ form a closed set of equations. They however only show fluctuations of the order $\mathcal{O}(\mathcal{Q}_i/q)$, hence remaining constant in the limit $q\rightarrow \infty$. Despite this effective lack of charge dynamics, the dots do not in fact behave as isolated lattice sites which would thermalize instantaneously. Indeed, we show via a proof by contradiction that such instantaneously thermalize is not generally possible for a connected lattice. Importantly, the results are shown to be independent of the dimensionality of the lattice.Comment: 14 pages, 1 figur

Angular Lens

We propose a single phase-only optical element that transforms different orbital angular momentum (OAM) modes into localized spots at separated angular positions on a transverse plane. We refer to this element as an angular lens since it separates out OAM modes in a manner analogous to how a converging lens separates out transverse wave-vector modes at the focal plane. We also simulate the proposed angular lens using a spatial light modulator and experimentally demonstrate its working. Our work can have important implications for OAM-based classical and quantum communication applications

OPTIMIZATION OF RECTANGULAR MICROSTRIP PATCH ANTENNA PARAMETERS IN L BAND BY EMPLOYMENT OF PROPOSED COMPOSITE NEGATIVE INDEX METAMATERIAL STRUCTURE IJECET © I A E M E

ABSTRACT In this paper work, a patch antenna and our proposed metamaterial patch antenna are simulated and compared. A rectangular microstrip patch antenna along with the innovative metamaterial structure is proposed at a height of 3.2mm from the ground plane. This work is mainly focused on increasing the potential parameters of microstrip patch antennas and analyzing the operation of proposed antenna. This structure produces a better performance compared to simple RMPA. The implementation of the metamaterial as the substrate in a rectangular microstrip patch antenna produces high value of return loss. Rectangular Microstrip Patch antenna loaded with metamaterial (MTM) is proposed for better improvement in the impedance bandwidth and reduction in the return loss at operating frequency 1.812 GHz. The proposed antenna is designed at a height 3.2 mm from the ground plane. At 1.812 GHz, the bandwidth is increased up to 20.4 MHz in comparison to RMPA alone of bandwidth 8.2 MHz. The Return loss of proposed antenna is reduced by -14.7dB. Microstrip Patch antenna has advantages over other antennas as it is lightweight, inexpensive, easy to fabricate and achieve radiation characteristics with higher return loss. CST MICROWAVE STUDIO is used to design the metamaterial based rectangular microstrip patch antenna. The result of our work suggest the proposed structure could be used in L band for wireless communications

Exploring the trends of breathlessness and mortality in conjunction with AQI in India’s coal capital, Dhanbad

Background: Air Quality Index (AQI) has been evidenced to be linked with various health problems including NCDs. Globally, the combined effect of ambient air and household air pollution causes 6.7 million premature deaths. Objective: A study was undertaken to understand various associations of AQI and morbidity data, indigenous to the coal capital region of India. Methodology: This was a cross-sectional study where district AQI data was obtained from the state of Jharkhand while mortality and morbidity data were collected from our medical college. MS Excel and SPSS were used to analyse the data. Results: During the study period, the AQI of Dhanbad has been moderate to poor. The lowest AQI was noted in May 2020 at 105 while the highest in June 2019 at 217. The highest admission, due to respiratory illness, was noted in May 2020 with AQI of 105. Using univariate analysis age categorisation was statistically significant, as the respiratory illness was highest in >85 years age group. In logistic regression, it has the highest odds of 2.9 (1.5-5.5). Conclusion: This region-specific indigenous information is expected to provide a valuable tool for Air quality managers for more focused action. It also highlights the health impacts of the worsening air quality

Probing the electronic and local structure of Sr2−x_{2-x}Lax_xCoNbO6_6 using near-edge and extended x-ray absorption fine structures

We report the electronic and local structural investigation of double pervoskites Sr$_{2-x}$La$_x$CoNbO$_6$ ($x=$ 0--1) using x-ray absorption near edge structure (XANES) and extended x-ray absorption fine structures (EXAFS) at the Nb, Co, and Sr $K$-edges. The $ab$ $initio$ simulations and detailed analysis of the Nb and Co $K$-edge XANES spectra demonstrate that the observed pre-edge features arise from the transition of 1$s$ electrons to the mixed $p-d$ hybridized states. We reveal a $z$-out Jahn-Teller (JT) distortion in the CoO$_6$ octahedra, which decreases monotonically due to an enhancement in the JT inactive Co$^{2+}$ ions with $x$ . On the other hand, the $z$-in distortion in NbO$_6$ octahedra remains unaltered up to $x=$ 0.4 and then decreases with further increase in $x$. This sudden change in the local coordination around Nb atoms is found to be responsible for the evolution of the antiferromagnetic interactions in $x \geqslant$ 0.6 samples. Also, we establish a correlation between the degree of octahedral distortion and intensity of the white line feature in the XANES spectra and possible reason for this are discussed. More interestingly, we observe the signature of KN$_1$ double electron excitation in the Sr $K$-edge EXAFS spectra for all the samples, which is found to be in good agreement with the $Z$+1 approximation. Further, the Co L$_{2,3}$ edge shows the reduction in the crystal field strength and hence an increase in the charge transfer energy ($\Delta_{ct}$) with the La substitution.Comment: submitte

Microbial beta glucosidase enzymes: recent advances in biomass conversation for biofuels application

The biomass to biofuels production process is green, sustainable, and an advanced technique to resolve the current environmental issues generated from fossil fuels. The production of biofuels from biomass is an enzyme mediated process, wherein β-glucosidase (BGL) enzymes play a key role in biomass hydrolysis by producing monomeric sugars from cellulose-based oligosaccharides. However, the production and availability of these enzymes realize their major role to increase the overall production cost of biomass to biofuels production technology. Therefore, the present review is focused on evaluating the production and efficiency of β-glucosidase enzymes in the bioconversion of cellulosic biomass for biofuel production at an industrial scale, providing its mechanism and classification. The application of BGL enzymes in the biomass conversion process has been discussed along with the recent developments and existing issues. Moreover, the production and development of microbial BGL enzymes have been explained in detail, along with the recent advancements made in the field. Finally, current hurdles and future suggestions have been provided for the future developments. This review is likely to set a benchmark in the area of cost effective BGL enzyme production, specifically in the biorefinery area