We have presented an analytic theory for the Casimir force on a Bose-Einstein condensate (BEC) which is confined between two parallel plates. We have considered Dirichlet boundary conditions for the condensate wave function as well as for the phonon field. We have shown that, the condensate wave function (which obeys the Gross-Pitaevskii equation) is responsible for the mean field part of Casimir force, which usually dominates over the quantum (fluctuations) part of the Casimir force.

Shyamal Biswas J. K. Bhattacharjee Dwipesh Majumder Kush Saha Nabajit Chakravarty

Even though composite fermions in the fractional quantum Hall liquid are well established, it is not yet known up to what energies they remain intact. We probe the high-energy spectrum of the 1/3 liquid directly by resonant inelastic light scattering, and report the observation of a large number of new collective modes. Supported by our theoretical calculations, we associate these with transitions across two or more composite fermions levels. The formation of quasiparticle levels up to high energies is direct evidence for the robustness of topological order in the fractional quantum Hall effect.

Trevor D. Rhone Dwipesh Majumder Brian S. Dennis Cyrus Hirjibehedin Irene Dujovne Javier G. Groshaus Yann Gallais Jainendra K. Jain Sudhansu S. Mandal Aron Pinczuk Loren Pfeiffer Ken West

We have focussed to study the even-denominator fractional quantum Hall (EDFQH) states observed in monolayer graphene. In this letter, we have studied polarization mainly for the two EDFQH states at filling fractions $\nu = 1/2, 1/4$, which are observed in an experimental study [Nat. Phys. 14, 930 (2018)] a few years ago. We have applied Chern Simon's gauge field theory to explain the possible variational wave functions for different polarized states and calculated their ground state energies using the Coulomb potential. We have chosen the lowest energy states using suitable combinations of flux attached with the electrons for different polarized states of those EDFQH states.

Moumita Indra Dwipesh Majumder

In this work, we have studied the effect of the repulsive speckle potential in a mixture of Bose-Einstein condensates in one dimension (1D) and two dimension (2D). We simulated linear and circular random speckle potentials in 1D and 2D, respectively. Our calculation shows that the condensate density forms a sharp ring in 2D, and the condensate is divided into two parts in 1D at a high impurity density of speckle potential. We have calculated the energy and chemical potential of the system by solving the Gross-Pitaevskii (GP) equation to see the stability of the condensate. In our study, we have seen that the nature of the impurity response is the same for one-dimensional and two-dimensional quantum droplets.

Avra Banerjee Saswata Sahu Dwipesh Majumder

We determine the lowest and higher order collective modes in both spin-conserving and spin-reversed sectors by calculating energy differences of the appropriate linear combinations of different levels of composite-fermion-excitons and the fully spin-polarized ground states at filling factors $\nu=1/3$, 2/5, 3/7, and 4/9. Apart from providing the detailed study of previously reported modes that have also been observed in the experiments, we predict additional higher energy modes at different filling factors. The lowest and the next higher spin-conserving modes have equal number of "magneto-rotons" and the number is the same as the number of filled effective Landau-like levels of composite fermions. The higher energy modes at $\nu =1/3$ merge with the lowest mode at long-wavelength. The spin-conserving modes do not merge at other filling factors. Apart from showing zero-energy spin-wave mode at zero momentum, thanks to Larmor's theorem, the lowest spin-reversed modes at the ferromagnetic ground states of $\nu=2/5$, 3/7, and 4/9 display one or more "spin-rotons" at negative energies signalling the unstable fully polarized ground states at sufficiently small Zeeman energies. The high energy spin-reversed modes also have spin-rotons but at positive energies. The energies of these excitations depend on the finite width of the quantum well as the Coulomb interaction gets screened. We determine finite thickness correction to the Coulomb interaction by the standard method of local density approximation and use them to calculate the critical energies such as rotons, long-wavelength, and short-wavelength modes which are detectable in inelastic light scattering experiments.

Dwipesh Majumder Sudhansu S. Mandal

In this paper the concept of extension of a Q-fuzzy ideal in semigroups has been introduced and some important properties have been studied.

Samit Kumar Majumder

We investigate the effects of a charge asymmetry on the spectrum of dileptons radiating from a quark gluon plasma. We demonstrate the existence of a new set of processes in this regime. The dilepton production rate from the corresponding diagrams is shown to be as important as that obtained from the Born-term quark-antiquark annihilation.

A. Majumder C. Gale

The notion of intuitionistic fuzzy sets was introduced by Atanassov as a generalization of the notion of fuzzy sets. S.K Sardar and S.K. Majumder unified the idea of fuzzy translation and fuzzy multiplication of Vasantha Kandasamy to introduce the concept of fuzzy magnified translation in groups and semigroups. The purpose of this paper is to intuitionistically fuzzify(by using Atanassov's idea) the concept of fuzzy magnified translation in semigroups. Here among other results we obtain some characterization theorems of regular, intra-regular, left(right) regular semigroups in terms of intuitionistic fuzzy magnified translation.

Sujit Kumar Sardar Manasi Mandal Samit Kumar Majumder

CLEO III upgrade was completed with the integration of Ring Imaging CHerenkov(RICH) detector for charged particle identification. The design of this cylindrical detector consists of LiF crystal radiators and multi-wire proportional chamber photon detectors coupled through a N2 filled expansion gap. Early performance on K/pion separation is presented.

Gobinda Majumder

The use of jet modification to study the properties of dense matter is reviewed. Different sets of jet correlations measurements which may be used to obtain both the space-time and momentum space structure of the produced matter are outlined.

A. Majumder