Selected works
Effect of correlated disorder on superconductivity in a kagome lattice: A Bogoliubov–de Gennes analysis
R. Kiran, Sudipta Biswas and Monodeep Chakraborty Effect of correlated disorder on superconductivity in a kagome lattice: A Bogoliubov–de Gennes analysis PhysRevB.110.184506 [article] [researchgate]
This paper investigates the superconducting properties of a two-dimensional s-wave superconductor on a kagome lattice subjected to correlated disorder. Using the Bogoliubov–de Gennes theory, we analyze the impact of disorder correlations on superconducting behavior. Additionally, we derive the stiffness formula for the kagome lattice and calculate its superfluid stiffness. An intriguing finding of our paper is the bimodal characteristic in the probability distribution of the superconducting pairing amplitude at higher disorder correlation strengths for intermediate values of the disordered potential. Our results provide valuable insights into how disorder correlations influence superconductivity and underscore the role of lattice geometry in shaping superconducting properties.
Immunomodulatory role of black tea in the mitigation of cancer induced by inorganic arsenic
R. Kiran, Swati Tyagi, Syed Abbas, Madhumita Roy and A. Taraphder Immunomodulatory role of black tea in the mitigation of cancer induced by inorganic arsenic Eur. Phys. J. Plus (2020) 135: 735 [article] [arxiv]
We present a model analysis of the tumor and normal cell growth under the influence of a carcinogenic agent, an immunomdulator (IM) and variable influx of immune cells including relevant interactions. The tumor growth is facilitated by carcinogens such as inorganic arsenic while the IM considered here is black tea (Camellia sinesnsis). The model with variable influx of immune cells is observed to have considerable advantage over the constant influx model, and while the tumor cell population is greatly mitigated, normal cell population remains above healthy levels. The evolutions of normal and tumor cells are computed from the proposed model and their local stabilities are investigated analytically. Numerical simulations are performed to study the long term dynamics and an estimation of the effects of various factors is made. This helps in developing a balanced strategy for tumor mitigation without the use of chemotherapeutic drugs that usually have strong side-effects
Population Migration and COVID
R. Kiran, Madhumita Roy, Syed Abbas and A. Taraphder Effect of population migration and punctuated lockdown on the spread of infectious diseases Nonauton. Dyn. Syst. 2021; 8:251-266 [article] [arxiv]
One of the critical measures to control infectious diseases is a lockdown. Once past the lockdown stage in many parts of the world, the crucial question now concerns the effects of relaxing the lockdown and finding the best ways to implement further lockdown(s), if required, to control the spread. With the relaxation of lockdown, people migrate to different cities and enhance the spread of the disease. This work presents the population migration model for n-cities and applies the model for migration between two and three cities. The reproduction number is calculated, and the effect of the migration rate is analyzed. A punctuated lockdown is implemented to simulate a protocol of repeated lockdowns that limits the resurgence of infections. A damped oscillatory behavior is observed with multiple peaks over a period.
Possible realization of hyperbolic plasmons in a few-layered rhenium disulfide
R. Kiran,Dimitar Pashov, Mark van Schilfgaarde, Mikhail I. Katsnelson, A. Taraphder, Swagata Acharya Possible realization of hyperbolic plasmons in a few-layered rhenium disulfide [arxiv]
The in-plane structural anisotropy in low-symmetric layered compound rhenium disulfide ($\text{ReS}_2$) makes it a candidate to host and tune electromagnetic phenomena specific for anisotropic media. In particular, optical anisotropy may lead to the appearance of hyperbolic plasmons, a highly desired property in optoelectronics. The necessary condition is a strong anisotropy of the principal components of the dielectric function, such that at some frequency range, one component is negative and the other is positive, i.e., one component is metallic, and the other one is dielectric. Here, we study the effect of anisotropy in $\text{ReS}_2$ and show that it can be a natural material to host hyperbolic plasmons in the ultraviolet frequency range. The operating frequency range of the hyperbolic plasmons can be tuned with the number of $\text{ReS}_2$ layers.