Short range correlations in relativistic nuclear matter models

Short range correlations are introduced using unitary correlation method in a relativistic approach to the equation of state of the infinite nuclear matter in the framework of the Hartree-Fock approximation. It is shown that the correlations give rise to an extra node in the ground-state wave-function in the nucleons, contrary to what happens in non-relativistic calculations with a hard core. The effect of the correlations in the ground state properties of the nuclear matter and neutron matter is studied. The nucleon effective mass and equation of state (EOS) are very sensitive to short range correlations. In particular, if the pion contact term is neglected a softening of the EOS is predicted. Correlations have also an important effect on the neutron matter EOS which presents no binding but only a very shallow minimum contrary to the Walecka model.Comment: 8pages, 4 figure

Giant Magneto-Impedance Behaviour in Ferro-Magnetic Materials

The ferromagnetic amorphous and nanocrystalhne materials exhibited a new phenomenon called Giant magneto-impedance (GMI). In this phenomenon these materials exhibited a sensitive change in an AC voltage with the application of a small DC magnetic field. GUI properties were investi-gated for four different compositions of amorphous and nanocrystalline ferromagnetic alloys for ribbon and wire samples. The impedance behaviour was strongly affected by magnetostriction of the materials. In nearly zero magneto-strictive amorphous wires about 100% change per Oe of mag-netic field was observed

Reforms in Indian agro-processing and agriculture sectors in the context of unilateral and multilateral trade agreements

In this paper, we explore the potential impacts of trade and investment-related policy reforms on India's agro-processing sector. We consider the direct effects of policy reforms within the processing sector, and the indirect effects on agro-processing of policy reforms in the primary agriculture sector, in the Indian economy as a whole, and in a multilateral framework. Towards this, we develop a 22-sector, 16-region version of the GTAP computable general equilibrium (CGE), global model for our analysis. We find that trade and investment-related reforms in agro-processing together can help the sector to grow. Policy reforms that stimulate investment and help to improve productivity will be crucial in offsetting the contractionary pressures of trade reform alone on the production of processed agricultural products. We also find that indirect effects on agroprocessing from India's policy reforms in other sectors are more important than reforms in agro-processing itself. Our findings argue for an economy-wide perspective when targeting reform or development of the agro-processing sector in India. Compared to trade reform, comprehensive domestic reforms in the agro-processing and agriculture sectors relating to investment are critical for achieving growth in agro-processing. However, while the impacts of trade reform per se seem to be small, trade reform - by ushering in a higher degree of competition - could itself be a stimulus for investment and productivity gains in India. At present, unilateral reforms, especially those that improve productivity in agroprocessing and in primary agriculture, are more important to agro-processing than multilateral trade reforms. Nevertheless, our findings also suggest the importance of pursuing a domestic reform agenda within a multilateral trading strategy that can accommodate the expected economic growth of India and its future role in global markets, with general equilibrium effects on agro-processing.Agriculture, Agro-processing, Trade agreements, CGE models

Self-consistent quantum effects in the quark meson coupling model

We derive the equation of state of nuclear matter including vacuum polarization effects arising from the nucleons and the sigma mesons in the quark-meson coupling model which incorporates explicitly quark degrees of freedom with quark coupled to the scalar and vector mesons. This leads to a softer equation of state for nuclear matter giving a lower value of incompressibility than would be reached without quantum effects. The {\it in-medium} nucleon and sigma meson masses are also calculated in a self-consistent manner.Comment: 10 pages, latex, 5 figure

Bulk Metallic Glasses and Nanostructured Materials

There is always a requirement for materials having higher performance than the existing one without any extra cost or even paying less. Demands ofhigh performance materials are increasing to improve the efficiency oftheproducts and produce micro-components for various applications. The polycrystalline materials prepared in conventional melting casting route have almost reached to its highest perfor-mance level. Hence, newerprocessing techniques are being adopted to develop newer materials so that the component should have smooth surface finish, minimum shrinkage etc. Excellent fillability and imprintability are prime requir-ements for the production of good quality micro-precision parts. In this regard, metallic glasses have achieved much attention due to its superior properties compared to the crystalline materials of same composition. The metallic glass can be prepared through rapid solidification techni-que where liquid metal can be poured on the surface of a rapidly rotating Cu-drum. In this process the cooling rate of the materials become 106K/s and the materials are obtai-ned in the form of about 30p,m thick ribbon, which is amorphous in nature. The isotropic nature of the material becomes immediate curiosity for functional applications, in particular Fe, Co and Ni based materials for magnetic application

Magnetic Characterisation of Amorphous and Nanocrystalline Materials

Amorphous and nanocrystalline ferromagnetic materials have an important place among the metallic materials due to their unique & favourable association of mechanical, elec-trical and magnetic properties like hysteresis, magneto-striction, domain wall movement and magnetoimpedance of these materials

Non-Abelian symmetries and disorder: a broad non-ergodic regime and anomalous thermalization

Symmetries play a central role in single-particle localization. Recent research focused on many-body localized (MBL) systems, characterized by new kind of integrability, and by the area-law entanglement of eigenstates. We investigate the effect of a non-Abelian $SU(2)$ symmetry on the dynamical properties of a disordered Heisenberg chain. While $SU(2)$ symmetry is inconsistent with the conventional MBL, a new non-ergodic regime is possible. In this regime, the eigenstates exhibit faster than area-law, but still a strongly sub-thermal scaling of entanglement entropy. Using exact diagonalization, we establish that this non-ergodic regime is indeed realized in the strongly disordered Heisenberg chains. We use real-space renormalization group (RSRG) to construct approximate excited eigenstates, and show their accuracy for systems of size up to $L=26$. As disorder strength is decreased, a crossover to the thermalizing phase occurs. To establish the ultimate fate of the non-ergodic regime in the thermodynamic limit, we develop a novel approach for describing many-body processes that are usually neglected by RSRG, accessing systems of size $L>2000$. We characterize the resonances that arise due to such processes, finding that they involve an ever growing number of spins as the system size is increased. The probability of finding resonances grows with the system size. Even at strong disorder, we can identify a large lengthscale beyond which resonances proliferate. Presumably, this eventually would drive the system to a thermalizing phase. However, the extremely long thermalization time scales indicate that a broad non-ergodic regime will be observable experimentally. Our study demonstrates that symmetries control dynamical properties of disordered, many-body systems. The approach introduced here provides a versatile tool for describing a broad range of disordered many-body systems.Comment: 25 pages, 21 figure