Pankaj Kumar Mishra
@portfolios.nith.ac.in
Assistant Professor
National Institute of Technology Hamirpur
Pankaj K. Mishra is an Assistant Professor in the Department of Electrical Engineering at NIT Hamirpur. He holds a B.E. in Electrical Engineering from Jorhat Engineering College and an M.Tech from MNNIT Allahabad. He completed his Ph.D. at IIT Kanpur in 2022, focusing on addressing challenges in control engineering. His diverse research interests include Intelligent Control, Nonlinear Control, Adaptive Control, Approximation-free control, Mathematical Control Theory, and Machine Learning. His passion lies in bridging the gap between theoretical research and practical implementation in control engineering.
EDUCATION
Doctorate of Philosophy (2022)
Control and Automation
Department of Electrical Engineering
Indian Institute of Technology Kanpur
Master of Technology (2016)
Control & Instrumentaion
Department of Electrical Engineering
MNNIT Allahabad
Bachelor of Engineering (2013)
Department of Electrical Engineering
Jorhat Engineering College (Dibrugarh University)
RESEARCH, TEACHING, or OTHER INTERESTS
Control and Systems Engineering, Electrical and Electronic Engineering
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Sanu Kumar Gangwar, Rajamanickam Ravisankar, Henrique Fabrelli, Paulsamy Muruganandam, and Pankaj Kumar Mishra
American Physical Society (APS)
We present the analytical and numerical results on the collective excitation spectrum of quasi-one-dimensional spin-orbit (SO) coupled spin-1 Bose-Einstein condensates. The collective excitation spectrum, using Bogoliubov-de-Gennes theory, reveals the existence of a diverse range of phases in the SO and Rabi ($k_L-\\Omega$) coupling plane. Based on eigenvalue of the excitation spectrum, we categorize the $k_L-\\Omega$ plane into three distinct regions. In region I, a stable mode with phonon-like excitations is observed. In region IIa, single and multi-band instabilities are noted with a gapped mode, while multi-band instability accompanied by a gapless mode between low-lying and first excited states is realized in region IIb, which also provides evidence of unstable avoided crossing between low-lying and first excited modes The gap between low-lying and first-excited states increases upon increasing the Rabi coupling while decreases upon increase of SO coupling. Using eigenvector analysis, we confirm the presence of the spin-dipole mode in the spin-like modes in Region II. We corroborate the nature of the collective excitation through real-time dynamical evolution of the ground state perturbed with the quench of the trap using the mean-field Gross-Pitaevskii model. This analysis suggests the presence of dynamical instability leading to the disappearance of the $0$-th component of the condensate. In Region III, mainly encompassing $\\Omega \\sim 0$ and finite $k_L$, we observe phonon-like excitations in both the first excited and the low-lying state. The eigenvectors in this region reveal alternative in- and out-of-phase behaviours of the spin components. Numerical analysis reveals the presence of a super stripe phase for small Rabi coupling in this region, wherein the eigenvector indicates the presence of more complicated spin-like-density mixed modes.
Rinku Bhatia, Pankaj Kumar Mishra, and Rekha Gupta
AIP Publishing
Anirudh Sivakumar, Pankaj Kumar Mishra, Ahmad A. Hujeirat, and Paulsamy Muruganandam
AIP Publishing
We investigate the scaling of the energy cascade in a harmonically trapped, turbulent, rotating Bose-Einstein condensate in two dimensions. We achieve turbulence by injecting a localized perturbation into the condensate and gradually increasing its rotation frequency from an initial value to a maximum. The main characteristics of the resulting turbulent state depend on the initial conditions, rotation frequency, and ramp-up time. We analyze the energy and the fluxes of kinetic energy by considering initial profiles without vortices and with vortex lattices. In the case without initial vortices, we find the presence of Kolmogorov-like scaling (k−5/3) of the incompressible kinetic energy in the inertial range. However, with initial vortex lattices, the energy spectrum follows Vinen scaling (k−1) at transient iterations. For cases with high rotating frequencies, Kolmogorov-like scaling emerges at longer durations. We observe positive kinetic energy fluxes with both initial states across all final frequencies, indicating a forward cascade of incompressible and compressible kinetic energy.
Nalinikanta Pradhan, Pardeep Kumar, Rina Kanamoto, Tarak Nath Dey, M. Bhattacharya, and Pankaj Kumar Mishra
American Physical Society (APS)
Recently, a method has been proposed to detect the rotation of a ring Bose-Einstein condensate, in situ, in real-time and with minimal destruction, using a cavity driven with optical fields carrying orbital angular momentum. This method is sensitive to the magnitude of the condensate winding number but not its sign. In the present work, we consider simulations of the rotation of the angular lattice formed by the optical fields and show that the resulting cavity transmission spectra are sensitive to the sign of the condensate winding number. We demonstrate the minimally destructive technique on persistent current rotational eigenstates, counter-rotating superpositions, and a soliton singly or in collision with a second soliton. Conversely, we also investigate the sensitivity of the ring condensate, given knowledge of its winding number, to the rotation of the optical lattice. This characterizes the effectiveness of the optomechanical configuration as a laboratory rotation sensor. Our results are important to studies of rotating ring condensates used in atomtronics, superfluid hydrodynamics, simulation of topological defects and cosmological theories, interferometry using matter-wave solitons, and optomechanical sensing.
R K Dokala, S Das, G Jangam, P K Mishra, and S Thota
IOP Publishing
Abstract Field-induced metamagnetic behavior and orbital-ordering (OO) in Yb-substituted (PrSr)MnO3 perovskites have been reported. The occurrence of distortions in the tetragonal crystal lattice leads to a reduction in the Mn − O 2 − Mn bond angle, which in turn governs the temperature and field-dependent long-range magnetic orderings. Extensive magnetization measurements reveal the high Curie temperature T C ∼ 302 K ferromagnetic (FM) phase and suggest the possibility of the existence of the OO in Pr0.45–x Yb x Sr0.55MnO3 accompanied by antiferromagnetic (AFM) Néel temperature, T N , as low as 158 K. Irreversible metamagnetic transitions from the AFM phase to the FM phase occur for a specific composition x = 0.05 (Yb5) until T ⩽ 220 K. The admixture of AFM and FM metastable states is quite robust in the investigated system, whereas the AFM state is mediated by Yb3+ ions, while the FM state arises as a result of field-driven thermo-magnetic kinetics. These results provide a constructive approach for designing novel spin-valve devices.
Akash Arya and Pankaj Kumar Mishra
Springer Science and Business Media LLC
Sonali Gangwar, Rajamanickam Ravisankar, S. I. Mistakidis, Paulsamy Muruganandam, and Pankaj Kumar Mishra
American Physical Society (APS)
We investigate the ground state and dynamics of one-dimensional spin-orbit coupled (SOC) quantum droplets within the extended Gross-Pitaevskii approach. As the SOC wavenumber increases, stripe droplet patterns emerge, with a flat-top background, for larger particle numbers. The surface energy decays following a power-law with respect to the interactions. At small SOC wavenumbers, a transition from Gaussian to flat-top droplets occurs for either a larger number of atoms or reduced intercomponent attraction. The excitation spectrum shows that droplets for relatively small SOC wavenumbers are stable, otherwise stripe droplets feature instabilities as a function of the particle number or the interactions. We also witness rich droplet dynamical features using velocity imprinting and abrupt changes in the intercomponent interaction or the SOC parameters. Characteristic responses include breathing oscillations, expansion, symmetric and asymmetric droplet fragmentation, admixtures of single and stripe droplet branches, and erratic spatial distributions suggesting the triggering of relevant instabilities. Our results reveal the controlled dynamical generation and stability properties of stripe droplets that should be detectable in current cold-atom experiments.
Rinkoo Bhatia, Pankaj Kumar Mishra, and Rekha Gupta
AIP Publishing
Prashant Kumar Shukla, Vandana Roy, Amit Kumar Chandanan, Vivek Kumar Sarathe, and Pankaj Kumar Mishra
Springer Science and Business Media LLC
Dhirendra Kumar, Pankaj Mishra, and Kottakkaran Sooppy Nisar
World Scientific Pub Co Pte Ltd
This paper aims to analyze the problem with the study of thermal and momentum transport with entropy generation in view of the second law of thermodynamics in Magneto hydrodynamics (MHD) micropolar fluid through porous medium under the consideration of the non-Darcy model, temperature-dependent viscosity and thermal conductivity. In practical situations at higher temperatures and high speed fluid flow, it becomes reasonable to consider variable fluid flow parameters. The governing boundary layer flow equations are first converted into a coupled system of the ordinary differential equations (ODE) under the assumption of differing plate temperatures by applying appropriate similarity transformations. A shooting method has been applied to solve ordinary differential equations numerically. The last effect of microrotation, magnetic field, variable viscosity coefficient, variable thermal conductivity, etc. on momentum and thermal transport has been depicted through various graphs. The table for skin friction coefficient and Nusselt number for ideal cases has been shown to validate the model by previous findings. It is seen that K and m enhance the velocity profile on their increment opposite to this M, [Formula: see text], F and Da have been found to reduce the velocity profile. Table 3 is constructed for numerical values of skin friction coefficient and Nusselt number for different values of parameters where it can be concluded that magnetic parameter M has a tendency to enhance the skin friction and heat transfer, while variable viscosity parameters have a tendency to decline the skin friction and heat transfer.
R K Dokala, S Das, P K Mishra, and S Thota
IOP Publishing
Abstract This study presents a comprehensive investigation of the structural, magnetic, electronic, and optical spectroscopic properties of tetragonal Zirconite Y1−x Ce x CrO4 polycrystals that were synthesized at various temperature ranges. The YCrO4 phase in its pristine state demonstrates ferromagnetic (FM) ordering, characterized by a Curie temperature, T C ∼ 9.3 K. Nevertheless, the introduction of magnetic Ce3+ in place of Y3+ ions results in a reduction of the T C and the appearance of a weak antiferromagnetic (AFM) behaviour, as indicated by the presence of a negative Curie–Weiss temperature (−10 K ≲ θ CW ≲ −30 K). It is observed that the introduction of moderate levels of Ce substitution leads to a significant increase in thermal irreversibility in the magnetization difference between field-cooled and zero-field-cooled states ΔM (M FC − M ZFC). This phenomenon indicates the substantial influence of magneto-crystalline anisotropy that exists within the system. Field-dependent magnetization data exhibits higher saturation magnetization values (M S ≳ (2.7 to 4.4) × 103 emu mole−1) and higher magneto-crystalline anisotropy (K 1 ∼ 2.18 to 3.41 J m−3) for the dilute dispersion of Ce (x ≤ 0.05). Local atomic environment probed by the electron spin resonance clearly indicates the presence of hyperfine splitting of Cr5+ spectra having a single d-electron ( t 2 g 1 e g 0 ) with orbital configuration bearing the possible doublet: F = 1 , 2 I = 3 2 J = 1 2 . On the other hand, the rare-earth Ce3+ spectra show hyperfine-doublets as 7 2 and 9 2 . Finally, the energy band-gap (E g = 2.14 to 2.38 eV, for x ∼ 0 to 0.1) determined from the diffuse reflectance spectroscopy reveals the emergence of intermediate localized states upon substitution of Ce3+.
Virendra K. Verma, Pankaj K. Mishra, Udit Agrawal, and John A. Santoshi
Medknow
ABSTRACT Introduction: In December 2019, a cluster of atypical cases of pneumonia was reported in Wuhan, China, which was later designated as Coronavirus disease 2019 (COVID-19) by the World Health Organization (WHO) on Feb 11, 2020. We all are facing a global pandemic, and it is very important to be clear that there is no correct roadmap to navigate this difficult situation. It is imperative to state that this global pandemic impacted the spine care services of our institute. In the present study, we have assessed the spine surgeries performed by orthopedic surgeons in terms of volume and etiologies during the COVID-19 pandemic and compared the data with a pre-COVID period. Materials and Methods: We retrospectively collected data from all patients who underwent spinal surgeries at our institute under the department of orthopedics from August 20, 2019 to August 20, 2020 (a total of 12 months duration). The data was then divided into two groups—pre-COVID period (August 20, 2019–February 19, 2020—6 months) and during the COVID pandemic (February 20, 2020–August 20, 2021—6 months). Results: A total of 140 patients underwent surgery at our institute from August 20, 2019 to August 20, 2020. Of these, 91 patients underwent surgery during the pre-COVID period, and 49 patients underwent surgery during the COVID pandemic. In this devastating phase of the pandemic, our department’s total number of surgeries significantly declined to 46.15%. The routine surgeries performed during the pandemic phase show a steep fall from 59.34% in the pre-COVID period to 10.20%. Conclusion: This paper is meant to focus attention on the exorbitant reduction in the operative workflow of the spine patients during the COVID-19 pandemic at a tertiary healthcare institute. It is the need of the hour that orthopedic surgeons maintain equilibrium while providing the best possible treatment to their patients and limiting the spread of the COVID-19 pandemic.
Prayas Chandra Patel, Pankaj K. Mishra, and Jyoti Kashyap
American Chemical Society (ACS)
Swarup K. Sarkar, Tapan Mishra, Paulsamy Muruganandam, and Pankaj K. Mishra
American Physical Society (APS)
We study the effect of atomic interaction on the localization and the associated dynamics of Bose-Einstein condensates in a one-dimensional quasiperiodic optical lattice and random Gaussian disordered potentials. When the interactions are absent, the condensates exhibit localization, which weakens as we increase the interaction strength beyond a threshold value for both potential types. We inspect the localized and delocalized states by perturbing the system via quenching the interaction strength instantaneously to zero and studying the dynamics of the condensate, which we further corroborate using the out-of-time-order correlator. The temporal behaviour of the time correlator displays regular dynamics for the localized state, while it shows temporal chaos for the delocalized state. We confirm this dynamical behaviour by analyzing the power spectral density of the time correlator. We further identify that the condensate admits a quasiperiodic route to chaotic dynamics for both potentials. Finally, we present the variation of the maximal Lyapunov exponents for different nonlinearity and disorder strengths that have a positive value in the regime where the time correlator function shows chaotic behaviour. Through this, we establish the strong connection between the spatially delocalized state of the condensate and its temporal chaos.
Prayas Chandra Patel, Pankaj Kumar Mishra, and Hem C. Kandpal
Springer Science and Business Media LLC
Prayas C. Patel, Pankaj Kumar Mishra, Jyoti Kashyap, and Surabhi Awasthi
Elsevier BV
Pankaj Kumar Mishra and Shashi Kant Verma
Springer Science and Business Media LLC
Pankaj Mishra, Dhirendra Kumar, Y. Dharmendar Reddy, and B. Shankar Goud
Elsevier BV
Prayas Chandra Patel, Pankaj K. Mishra, and Hem Chandra Kandpal
American Chemical Society (ACS)
Sonali Gangwar, Rajamanickam Ravisankar, Paulsamy Muruganandam, and Pankaj Kumar Mishra
American Physical Society (APS)
We present the numerical results of the structure and dynamics of the self-bound ground state arising solely because of the presence of beyond mean field quantum fluctuation in spin-orbit coupled binary Bose-Einstein condensates in one dimension. Depending upon spin-obit (SO) and Rabi couplings, we observe that the ground state exhibits either quantum-bright (plane) or quantum-stripe soliton nature. We find an analytical soliton solution for non-zero SO coupling that matches quite well with the numerical results. Further, we investigate the dynamical stability of these solitons by adopting three protocols, such as (i) adding initial velocity to each component, (ii) quenching the SO and Rabi coupling parameters at initial and finite time, and (iii) allowing collision between the two spin-components by giving equal and opposite direction velocity to them. Many interesting dynamical features of the solitons, like, multi-fragmented, repelling, and breathing in time and space-time, are observed. For given Rabi coupling frequency, the breathing frequency of the soliton increases upon the increase in SO coupling, attaining a maximum at the critical SO coupling where the phase transition from the bright to stripe soliton occurs. We observe that the maximum breathing frequency exhibits power law dependence on the Rabi coupling frequency with an exponent ∼ 0 . 16 . The quenching of SO and Rabi coupling frequency leads to dynamical phase transition from bright to stripe soliton and from breathing stripe to a bright soliton. In the absence of the SO and Rabi couplings, depending upon the velocity of the up-spin and down-spin components, the collision between them is either elastic or inelastic, which is consistent with the earlier numerical and experimental observation. However, in the presence of coupling parameters, the collision appears to be inelastic and quasi-elastic in nature.
Prakash Chandra Sharma, Rohit Raja, Santosh Kumar Vishwakarma, Sanjiv Sharma, Pankaj Kumar Mishra, and Vivek Singh Kushwah
Multimedia Tools and Applications Springer Science and Business Media LLC
Pankaj Mishra, Dhirendra Kumar, Y. Dharmendar Reddy, and B. Shankar Goud
Wiley
AbstractThe present analysis is done for the investigation of the effect of various physical parameters on magnetohydrodynamic Williamson nanofluid boundary layer flow past a wedge through porous media taking a non‐Darcy–Falkner–Skan model with consideration of varying wall temperature, variable viscosity, the effect of Brownian motion, and thermophoresis in the presence of heat source. The corresponding governing equations under the appropriate boundary conditions are first converted into ordinary differential equations (ODEs) in view of similarity transformations. Application of shooting method has been made to deal with these ODEs, and the effects of various parameters on nondimensional velocity, temperature, and concentration are investigated through graphs. Also, the effects of various parameters on surface skin friction, heat, and mass transfer rates are analyzed and are shown in Table 3. It has been noticed that heat and mass transfer rates are enhanced with variable viscosity coefficient and reduced with Brownian motion and thermophoresis parameters. As a significant outcome, the skin friction is found to be increased with increasing values of the Williamson parameter while it is found to be decreased with increasing value of variable viscosity coefficient. At last, validation of the current findings is attended to after comparing with similar results obtained earlier.
B. Krishna Rao, Gaurav Singh, Gopal Kumar, V.C. Pande, Narendra K. Lenka, D. Dinesh, P.K. Mishra, and A.K. Singh
Elsevier BV