Devanagari

These tables are designed for use by teachers and learners of Devanagari, and may be freely incorporated into course materials, printed for reference, or read online. Please acknowledge HUF! Many thanks to our calligraphers, Aruna Kharod and Bipul Pandey.Asian Studie

Power Series Correction to Single Particle Electron Green's Function: Application to 1D Holstein Chain

Electrons in materials undergo numerous complex interactions among themselves, the external fields, as well as the constituent atomic lattice. The strength of such many-body interactions depends on various factors such as the electronic configuration of the host material, the presence of doping and defects, spins of carrier and lattice elements, etc. In the thermodynamic limit, these interactions are often treated as bosons that interact with the electrons in the system and manifest as side bands (replicas or satellites) in the electronic band structure seeping spectral weight and renormalizing the band structure obtained from purely electronic calculations. In ab-initio calculations, when the strength of such electron-boson interaction is weak, it is not only justified to neglect these interactions completely but also pragmatic for reasons ranging from tractability to associated computational cost. This is because the effect of electron-boson interaction is minute compared to the electronic energy scale of the problem. However, in many systems, especially organic semiconducting materials, the bosonic vibrations (stretching modes) of the molecule are strongly coupled with the electron. Furthermore, the bosonic energy scale is comparable to the electronic energy scale in these problems. Hence, neglecting the effect of electron-boson interactions in electronic spectra in such systems is myopic at best and catastrophic at worst. In the context of a single electron two orbital Holstein system coupled to dispersionless bosons, we develop a general method to correct single-particle Green’s function and electronic spectral function using an integral power series correction (iPSC) scheme. We then outline the derivations of various flavors of cumulant approximation through the iPSC scheme and explain the assumptions and approximations behind them. Finally, we compute and compare iPSC spectral function with cumulant and exact diagonalized spectral functions and elucidate three regimes of this problem - two that cumulant explains and one where cumulant fails. We find that the exact and the iPSC spectral functions match within spectral broadening across all three regimes. In order to scale our method to large systems, we then develop an ODE-based Power series correction(dPSC) formalism that goes beyond the cumulant approximation. We implement it to a 1D Holstein chain for a wide range of coupling strengths in a scalable and inexpensive fashion at both zero and finite temperatures. We show that this first differential formalism of the power series is qualitatively and quantitatively in excellent agreement with exact diagonalization results on the 1D Holstein chain with dispersive bosons for a large range of electron-boson coupling strength. We also investigate carrier mass growth rate and carrier energy displacement across a wide range of coupling strengths. We also present a faster second differential formalism which is very much similar to self-consistent cumulant formalism. We show the regime where this method is applicable and where it diverges. Finally, we present a heuristic argument that predicts most of the rich satellite structure without explicit calculation

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Going beyond the Cumulant Approximation:Power Series Correction to the Single-Particle Green's Function in the Holstein System

In the context of a single-electron two orbital Holstein system coupled to dispersionless bosons, we develop a general method to correct the single-particle Green's function using a power series correction (PSC) scheme. We outline the derivations of various flavors of cumulant approximation through the PSC scheme explaining the assumptions and approximations behind them. Finally, we compare the PSC spectral function with cumulant and exact diagonalized spectral functions and elucidate three regimes of this problem - two where the cumulant explains and one where the cumulant fails. We find that the exact and the PSC spectral functions match within spectral broadening across all three regimes.</p

Going beyond the Cumulant Approximation:Power Series Correction to the Single-Particle Green's Function in the Holstein System

In the context of a single-electron two orbital Holstein system coupled to dispersionless bosons, we develop a general method to correct the single-particle Green's function using a power series correction (PSC) scheme. We outline the derivations of various flavors of cumulant approximation through the PSC scheme explaining the assumptions and approximations behind them. Finally, we compare the PSC spectral function with cumulant and exact diagonalized spectral functions and elucidate three regimes of this problem - two where the cumulant explains and one where the cumulant fails. We find that the exact and the PSC spectral functions match within spectral broadening across all three regimes.</p

Unmet need for family planning and associated factors among currently married women in Nepal: A further analysis of Nepal Demographic and Health Survey-2022.

IntroductionFamily planning (FP) is crucial for improving maternal and newborn health outcomes, promoting gender equality, and reducing poverty. Unmet FP needs persist globally, especially in South Asia and Sub-Saharan Africa leading to unintended pregnancies, unsafe abortions, and maternal fatalities. This study aims to identify the determinants of unmet needs for FP from a nationally representative survey.MethodsWe analyzed the data of 11,180 currently married women from nationally representative Nepal Health Demographic Survey 2022. We conducted weighted analysis in R statistical software to account complex survey design and non-response rate. We conducted univariate and multivariable binary and multinomial logistic regression to assess association of unmet need for FP with independent variables including place of residence, province, ecological belt, ethnicity, religion, current age, participant's and husband's education, occupation, wealth quintile, parity, desire for child, and media exposure.ResultsThe total unmet FP need was 20.8% (95%CI: 19.7, 21.9) accounting 13.4% (95%CI: 12.5, 14.4) for unmet need for limiting and 7.4% (95%CI: 6.8, 8.0) for unmet for spacing. Lower odds of total unmet need for FP were present in 20-34 years and 35-49 years compared to ConclusionNepal faces relatively high unmet FP needs across various socio-demographic strata. Addressing these needs requires targeted interventions focusing on age, ethnicity, religion, education, and socio-economic factors to ensure universal access to FP services