Structure and swelling dynamics of ultra thin films of CdS-polyacrylamide nanocomposite material were studied using gravimetric techniques and x-ray reflectivity. Ultrathin films of the polymer and the nanocomposite were coated on hydrophilic Si (100) substrate using spin coating. The thickness of the composite films vary non-monotonically with spinning speed and were found to lie in discrete “bands” of thicknesses separated by “forbidden regions” unlike pure polymer films. Modified internal structure of the coils due to polymer-particle interaction was found to play a significant role in describing the novel features of the nanocomposite films. To study the mass uptake, the films were exposed to the H2O vapour and the weights of the films were recorded as functions of exposure time. The observed non-Fickian transport was explained in terms of alignment of free volume due to confinement of restricted polymer chains. To study swelling dynamics, the films were exposed to the H2O vapour and x-ray reflectivity scans were collected as functions of exposure time. The swelling dynamics of the nanocomposite films were explained in terms of a model which takes into account the polymer-particle interaction. A fraction of polymer segments that are in direct contact with the nanoparticles observed slower dynamics as compared to the free chain swelling. Larger values of excluded volume parameters corresponding to restricted segments as compared to the free segments were explained in terms of enhancement of monomer-monomer interaction through particle attachment.

It is known that classical information can be completely hidden from asubsystem in two distinct ways. The information may be moved to another location, orit may be encoded as correlations between a pair of subsystems. Most generally, theinformation will be hidden as a combination of these two. Can we hide quantuminformation in the same way? Consider a physical process which maps an arbitraryquantum state to a fixed state. If the final state is independent of the input, thenwe prove that this missing, or hidden, information is wholly encoded in theremainder of Hilbert space with no information stored in the correlations betweenthe two subsystems. We call this the “no-hiding theorem”. Thus, unlike classicalinformation, quantum mechanics allows only one way to completely hide an arbitraryquantum state from one of its subsystems, i.e., by moving it to the remainingsubsystems. We will discuss various applications of this theorem in quantumteleportation, thermalisation and finally in black hole information loss paradox.

The application of the effect of magneto-resistance in magneto-electronics, field sensors and random access memory elements and others created a huge interest on the studies of the magnetic and transport properties of the magnetic material realized in low dimensions. The interplay between magnetization and localization is central to the behavior of many artificially tailored materials and has given rise to phenomena such as giant magneto-resistance in metallic multi-layers, spin polarons in high Tc superconductors and skyrmion in two dimensional electron gases in semiconductors. At low temperatures, transport measurements in ferromagnetic materials indicate remarkable modification of the quantum correction to the 2D magneto-conductivity in the weakly localized regime, and negative magneto-resistance (MR) at high field suggesting suppression of weak electron localization (WEL) and spin disorder scattering. Moreover, the observation of anisotropic magneto-resistance (AMR) and anomalous Hall effect in ferromagnets emphasizes the importance of spin-orbit scattering in the transport properties of the low-dimensional ferromagnetic material. In order to get a better understanding regarding the transport properties of the ferromagnetic materials we will study the magneto-conductivity of a two-dimensional ferromagnet in presence of elastic scattering as well as spin-orbit scattering. Here we will provide a general description of the electronic transport in ferro-magnets for arbitrary direction of magnetization and magnetic field. By means of the diagrammatic perturbation technique, an analytical results for the magneto-conductivity has been obtained as a function of the magnetization and characteristic relaxation times due to elastic, inelastic and spin-orbit scattering. The result shows a strong dependence of the orientation of the magnetization with respect to the plane of the system on the conductivity. Depending on the orientation and strength of the magnetization and the coupling of the electronic spin with the magnetization both negative and positive magneto-resistance has been predicted. In addition, it is shown that, in order to explain the experimental variation of the conductivity in thin ferromagnetic films [1], electron-electron interaction and domain wall scattering must be considered.