Levitation of non-magnetizable droplet inside ferrofluid

The central theme of this work is that a stable levitation of a denser non-magnetizable liquid droplet, against gravity, inside a relatively lighter ferrofluid -- a system barely considered in ferrohydrodynamics -- is possible, and exhibits unique interfacial features; the stability of the levitation trajectory, however, is subject to an appropriate magnetic field modulation. We explore the shapes and the temporal dynamics of a plane non-magnetizable droplet levitating inside ferrofluid against gravity due to a spatially complex, but systematically generated, magnetic field in two dimensions. The effect of the viscosity ratio, the stability of the levitation path and the possibility of existence of multiple-stable equilibrium states is investigated. We find, for certain conditions on the viscosity ratio, that there can be developments of cusps and singularities at the droplet surface; this phenomenon we also observe experimentally and compared with the simulations. Our simulations closely replicate the singular projection on the surface of the levitating droplet. Finally, we present an dynamical model for the vertical trajectory of the droplet. This model reveals a condition for the onset of levitation and the relation for the equilibrium levitation height. The linearization of the model around the steady state captures that the nature of the equilibrium point goes under a transition from being a spiral to a node depending upon the control parameters, which essentially means that the temporal route to the equilibrium can be either monotonic or undulating. The analytical model for the droplet trajectory is in close agreement with the detailed simulations. (See draft for full abstract).Comment: This article has been published in a revised form in Journal of Fluid Mechanics http://dx.doi.org/10.1017/jfm.2018.733. Copyright: copyright holde

Topology of Quantum Grey Soliton in Multi-Component Inhomogeneous Bose-Einstein Condensates

We study the dispersion mechanism of Lieb mode excitations of both single and multi component ultra-cold atomic Bose gas, subject to a harmonic confinement through chirp management. It is shown that in some parameter domain, the hole-like excitations lead to the soliton's negative mass regime, arising due to the coupling between chirp momentum and Kohn mode. In low momenta region the trap considerably affects the dispersion of the grey soliton, which opens a new window to observe Lieb-mode excitations. Further, we extend our analysis to binary condensate, which yields usual shape compatible grey-bright soliton pairs. The inter-species interaction induces a shift in the Lieb-mode excitations, where the pair can form a bound state. We emphasize that the present model provides an opportunity to study such excitations in the low momenta regime, as well as the formation of bound state in binary condensate.Comment: 9 pages, 7 figure

The effect of a light radion on the triviality bound on higgs mass

In this paper we study how the triviality bound on higgs mass in the context of the SM is modified by a light stabilized radion of the Goldberger-Wise variety. Our approach is inherently perturbative. Including the radion contribution to \bt(\l) and \bt(g_t) to one loop we evolve the higgs self coupling \l from the cut off \L(=\vphi) down to the EW scale $\mu_0 = v$. The triviality bound is obtained by requiring that \l(\L) = \sqrt{4 \pi} which is the perturbative limit. We also study the effect of small changes in the UVBC on the triviality bound both in the presence and absence of a light radion.Comment: 9 pages, latex, 2 eps figure

Infrared spectra of dimethylnaphthalenes in the gas phase

We report the infrared spectra at 0.5 cm-1 resolution of three dimethylnaphthalenes (DMNs), namely 1,5-DMN, 1,6-DMN and 2,6-DMN in the gas phase at an elevated temperature recorded with the help of a variable path-length cell. DFT calculations have been carried out at B3LYP levels of theory with 6-31G as basis set to determine the harmonic frequencies and intensities of the DMNs to assign the experimentally observed spectra. We have compared the experimentally observed and theoretically calculated spectra of the dimethylnaphthalenes and assignments have been made. The observed and predicted frequencies and relative intensities are generally in good agreement. The intense aromatic C-H out-of-plane bending vibration observed around 800 cm-1 and three methyl C-H symmetric and asymmetric stretching vibrations around 2900 cm-1 have been recognized as unique bands to identify various DMNs in a mixture. The high-resolution IR spectroscopy of these three important polycyclic aromatic hydrocarbons which are present in the atmosphere have been discussed

Muon anomaly and a lower bound on higgs mass due to a light stabilized radion in the Randall-Sundrum model

We investigate the Randall-Sundrum model with a light stabilized radion (required to fix the size of the extra dimension) in the light of muon anomalous magnetic moment $a_\mu [= \frac{(g - 2)}{2}]$. Using the recent data (obtained from the E821 experiment of the BNL collaboration) which differs by $2.6 \sigma$ from the Standard Model result, we obtain constraints on radion mass \mphi and radion vev \vphi. In the presence of a radion the beta functions \beta(\l) and $\beta(g_t)$ of higgs quartic coupling (\l) and top-Yukawa coupling ($g_t$) gets modified. We find these modified beta functions. Using these beta functions together with the anomaly constrained \mphi and \vphi, we obtain lower bound on higgs mass $m_h$. We compare our result with the present LEP2 bound on $m_h$.Comment: Version to be appeared in IJMP