Nanostructures are produced on metal and semiconductor surfaces in a controllable manner via low energy ion bombardment. The resultant materials are probed with scanning probe microscopy, x-ray photoelectron spectroscopy and low energy ion scattering. A variety of nanostructures such as ripple, dot and hole are formed and controlled their shapes and sizes by tuning the ion beam parameters and ion target geometry. The self-organized nanoclusters produced by ion bombardment display quantum size effects. Neutralization of scattered alkali-metal ions is used to probe the electronic states of the nanoclusters.The work function change accompanying oxygen adsorption on metals is not always positive, as would be expected due to the surface dipole. I shall also discuss that the low energy alkali ions could be used to investigate the contribution of the dipole to the local potential near a Ta surface atom

Laser beams can be used to decelerate gas phase atoms in an ultra-high vacuum chamber. A set of six counter-propagating red-detuned circularly polarized low intensity cw laser radiations originating from a a single source and a quadrupolar magnetic field produced by coils in an anti-Helmholtz configuration can control the atomic motion in a three dimensional space. Under certain optimum conditions of laser detuning, laser intensity and the magnetic field gradient the velocity dependent optical vicous force and the position dependent harmonic force will win over the atom’s tendency to escape and lower the atomic velocity as well as push them towards the centre of the trup. We shall describe the magneto-optic trap developed in our department for confinement of Rb atoms. The trap chamber is kept at one nano-Torr pressure and Rb samples are introduced at a pressure of 10-100 Nano-Torr. The cold atom cloud has an estimated temperature of 130 micro-Kelvin and the number of confined atoms is 106 in a cloud with an approximate radius of nearly 0.1 mm.the cloud can be compressed by increasing the field current. Further work on guiding of the cold atom cloud to a second trap for achieving Bose Einstein Condensation (BEC) will be discussed.

We will discuss the design of structured composite materials whose electromagnetic response can be described by effective medium parameters such as the dielectric permittivity and magnetic permeability. We will more particularly discuss metamaterials with negative material parameters and present our recent results on optical metamaterials in perspective. Extremely singular photonic systems using superstructures of metamaterials with positive and negative material parameters will be presented

The breaking of chiral symmetry of light quarks at zero temperature in the presence of strong quantizing magnetic field is studied using Nambu-Jona-Lasinio (NJL) model with a Thomas-Fermi type semi-classical formalism. It is found that the dynamically generated light quark mass can never become zero if the Landau levels are populated and increases with the increase of magnetic field strength.

A new method of approximation scheme, with potential of application to a general , interacting quantum theory is presented. The method is non-perturbative, self-consistent, systematically improvable and uniformly applicable for arbitrary strength of interaction. It thus overcomes the limitations of the existing methods, such as the perturbation theory, the variational method, the WKBJ method and other approximation schemes. The method has been successfully applied to a variety of interacting quantum systems including the anharmonic/ double well oscillators (with general quadratic-, quartic-, sextic- and octic couplings), the hydrogen atom and to the (lambda phi^4) quantum-field theory. The method yields important insight to the structure and stability of the physical vacuum. The results are shown to be consistent with the exact results predicted by supersymmetric quantum mechanics wherever applicable. Possible application to quantum statistics and finite temperature field theory is discussed.