A5042873373- Cold Atom Physics and Bose-Einstein Condensates
- Physics of Superconductivity and Magnetism
- Quantum, superfluid, helium dynamics
- Iron-based superconductors research
- Rare-earth and actinide compounds
- Strong Light-Matter Interactions
- Orbital Angular Momentum in Optics
- Nonlinear Dynamics and Pattern Formation
- Spectroscopy and Laser Applications
- Magnetic and transport properties of perovskites and related materials
- Atomic and Subatomic Physics Research
- Topological Materials and Phenomena
- Quantum Electrodynamics and Casimir Effect
- Quantum optics and atomic interactions
- Amyloidosis: Diagnosis, Treatment, Outcomes
- Superconductivity in MgB2 and Alloys
Virginia Tech
2023-2025
Indian Institute of Technology Kharagpur
2019-2024
University of Cambridge
2011-2015
Tata Institute of Fundamental Research
2015
We report inelastic neutron scattering measurements of the magnetic excitations in SrFe2As2, parent a family iron-based superconductors. The data extend throughout Brillouin zone and up to energies ~260meV. An analysis with local-moment J_1-J2 model implies very different in-plane nearest-neighbor exchange parameters along $a$ $b$ directions, both orthorhombic tetragonal phases. However, spectrum calculated from J1-J2 deviates significantly our data. show that qualitative features cannot be...
The recent realization of a binary dipolar Bose-Einstein condensate [A. Trautmann et al., Phys. Rev. Lett. 121, 213601 (2018)] presents new exciting aspects for studying quantum droplets and supersolids in mixture. Motivated by this experiment, we study the ground-state phases dynamics Dy-Dy bosonic mixture exhibits qualitatively novel rich physics. Relying on three-dimensional numerical simulations extended Gross-Pitaevskii framework, unravel phase diagrams characterize their different...
We use point contact spectroscopy to probe $\rm{AEFe_2As_2}$ ($\rm{AE=Ca, Sr, Ba}$) and $\rm{Fe_{1+y}Te}$. For $\rm{AE=Sr, Ba}$ we detect orbital fluctuations above $T_S$ while for AE=Ca these start below $T_S$. Co doping preserves the K suppresses it. The are only seen at those dopings temperatures where an in-plane resistive anisotropy is known exist. predict of $\rm{Fe_{1+y}Te}$ Our data examined in light recent work by W.-C. Lee P. Phillips (arXiv:1110.5917v2). also study how joule...
A Faraday-wave-like parametric instability is investigated via mean-field and Floquet analysis in immiscible binary Bose-Einstein condensates. The condensates form a so-called \textit{ball-shell} structure two-dimensional harmonic trap. To trigger the dynamics, scattering length of core condensate periodically modulated time. We reveal that dynamics interface becomes unstable towards formation oscillating patterns. oscillates sub-harmonically exhibiting an $m$-fold rotational symmetry can be...
The recent experimental realization of the heteronuclear dipolar mixture Dy and Er atoms opens fascinating prospects for creating intriguing novel phases in quantum gases. experimentally measured value intraspecies $s$-wave scattering length $^{166}\mathrm{Er}$ condensate a $^{164}\mathrm{Dy}\text{\ensuremath{-}}^{166}\mathrm{Er}$ is larger than its implies that itself will not be regime dominated dipole-dipole interaction (DDI). However, we find presence $^{164}\mathrm{Dy}$ with high...
We investigate the quench dynamics of quasi-one- and two-dimensional dipolar Bose-Einstein condensates $^{164}\mathrm{Dy}$ atoms under influence a fast rotating magnetic field. The field thus controls both magnitude sign potential. account for quantum fluctuations, critical to formation exotic droplet supersolid phases in extended Gross-Pitaevskii formalism, which includes so-called Lee-Huang-Yang correction. An analytical variational ansatz allows us obtain phase diagrams superfluid phases....
We conduct a theoretical study of the creation and dynamics vortices in two-dimensional binary Bose-Einstein condensate with mass imbalance between species. To initiate dynamics, we use one or two rotating paddle potentials species, while other species is influenced only via interspecies interaction. In both number dominant sign are determined by rotation frequency potential. Clusters positive negative form at low comparable to that trap when using single contrast, same tend dominate as...
Three-component Bose-Einstein condensates (BECs) offer a rich platform for exploring inquisitive quantum phenomena. We investigate the Rayleigh-Taylor instability at two interfaces in phase-separated three-component BEC mean-field framework. The system can be instigated various ways owing to versatility of and subsequent dynamics certain cases has been studied detail. also study impact immiscibility intermediate component on onset system. rotational symmetry breaks when atom-atom interaction...
The twin issues of the nature ``normal'' state and competing order(s) in iron arsenides are central to understanding their unconventional, high-${T}_{c}$ superconductivity. We use a combination transport anisotropy measurements on detwinned $\mathrm{Sr}{({\mathrm{Fe}}_{1\ensuremath{-}x}{\mathrm{Co}}_{x})}_{2}{\mathrm{As}}_{2}$ single crystals local density approximation plus dynamical mean field theory (LDA + DMFT) calculations revisit these issues. peculiar resistivity its evolution with...
Point contact spectroscopy reveals a gap-like feature above the magnetic and structural transition temperatures for underdoped Ba(F e1-xCox)2As2, SrF e2As2 F e1+yT e.The conductance spectrum starts showing an enhancement at as high 177 K BaF (TN ∼ 132 K) 250 192 K).Possible origins this are discussed in light of recent experimental claims nematicity these materials.We construct modified phase diagram Co-doped Ba122 existing TN TS regime.
In this paper, we have formulated a theory for the microscopic interaction of asymmetric Laguerre-Gaussian (aLG) beam with atomic Bose-Einstein condensate (BEC) in harmonic trap. Here asymmetry is introduced to an LG considering complex-valued shift Cartesian plane keeping axis and its vortex states co-axial trap BEC. Due inclusion nature, multiple quantized circulations are generated beam. We show how these transferred BEC resulting superposition matter states. The calculated Rabi...
We present a theoretical study of spin-orbit coupled spin-1 Bose-Einstein condensate under the influence sinusoidally varying magnetic fields. In ground state ferromagnetic condensate, we investigate topological excitations in system arising due to combined effect Rashba coupling and an in-plane field. this work, offer comparative for various choices fields $x\rm{-}y$ plane. For fixed field strength, sustains rich variety exotic vortex structures ranging from vortex-antivortex lattices...
We use point contact spectroscopy (PCS) to probe the superconducting properties of electron doped $\rm{Ba(Fe_{1-x}Co_x)_2As_2}$ ($\rm{x = 0.05, 0.055, 0.07, 0.08}$) and hole $\rm{Ba_{0.8}K_{0.2}Fe_2As_2}$. PCS directly probes low energy density states via Andreev reflection, revealing two distinct gaps in both compound families. Apart from underdoped $\rm{Ba(Fe_{1-x}Co_{x})_2As_2}$, excess current due reflection for compounds follows typical BCS temperature dependence. For dependence...
Recent experimental realization of the heteronuclear dipolar mixture Dy and Er atoms opens fascinating prospects for creating intriguing novel phases in quantum gases. The experimentally measured value intra-species $s$-wave scattering length $^{166}$Er condensate a $^{164}$Dy-$^{166}$Er is larger than its length, implies that itself will not be regime dominated dipole-dipole interaction (DDI). However, we find presence $^{164}$Dy with high magnetic moment induces droplet nucleation...