On the ground state of metallic hydrogen

A proposed liquid ground state of metallic hydrogen at zero temperature is explored and a variational upper bound to the ground state energy is calculated. The possibility that the metallic hydrogen is a liquid around the metastable point (rs = 1.64) cannot be ruled out. This conclusion crucially hinges on the contribution to the energy arising from the third order in the electron-proton interaction which is shown here to be more significant in the liquid phase than in crystals

A Kondo impurity in a disordered metal: Anderson's theorem revisited

We consider a local moment which is coupled by a non-random Kondo $J$ to a band of conduction electrons in a random potential. We prove an analog of Anderson's theorem in a large-N limit of this model. The theorem states that when the disorder is weak, the disorder-averaged low-temperature thermodynamics is independent of the strength of the disorder; remarkably, it further states that fluctuation effects in the long-time limit are {\it independent even of the realization of the disorder}. We discuss the relationship of this theorem to theoretical and experimental studies of similar problems.Comment: 4 pages, RevTe

Superconductivity in hole-doped C60 from electronic correlations

We derive a model for the highest occupied molecular orbital band of a C60 crystal which includes on-site electron-electron interactions. The form of the interactions are based on the icosahedral symmetry of the C60 molecule together with a perturbative treatment of an isolated C60 molecule. Using this model we do a mean-field calculation in two dimensions on the [100] surface of the crystal. Due to the multi-band nature we find that electron-electron interactions can have a profound effect on the density of states as a function of doping. The doping dependence of the transition temperature can then be qualitatively different from that expected from simple BCS theory based on the density of states from band structure calculations

Contributions to Indian Economic Analysis: A Survey

Any survey of contributions to economic analysis in India, even though confined to the post-war years and to issues arising from domestic economic events and policy, runs into exceptional difficulties. Not only has practically every conceivable problem been raised and discussed by economists, in a country where interest in economic issues dates back at least to the latter half of the 19th century but there have also been numerous committees and commissions. The Survey does not extend to the growing number of contributions to general theoretical economic analysis that Indian economists have begun to make, as is evident from the contents of reputed journals in the last decade. This Survey, therefore, is neither a comprehensive account of the state of economic research in the country nor does it pretend to give an exhaustive picture of the policy issues that have been discussed on the Indian scene since 1947 when India gained independence. The Survey is broadly divided into three areas i.e. planning theory and techniques, agriculture and foreign trade. The vast majority of India's policy issues and analytical literature, fall within one or more of these categories. Because agriculture is the overwhelmingly important economic activity in the economy and its capacity to act as a significant brake on growth via its role as the supplier of wage goods to other sectors has been increasingly appreciated, this sector has also attracted considerable economic analysis

Health Care and Women's Empowerment: The role of Self Help Groups

Over the last couple of decades the concept of Self Help Groups (SHGs) and its potential as an effective tool to alleviate poverty and empower women has garnered considerable interest worldwide. Considering the importance given by policy makers across various nations to the group approach while conceptualizing, formulating and implementing any scheme or programme for the welfare of marginalized and underprivileged sections of the society (especially women), we identified the need to critically examine and explore the role of SHGs in the empowerment of women with a special emphasis on health status. To date, the functioning of SHGs has essentially been viewed only from an economic perspective. The existing approach puts encourages the economic development of women, with SHGs a mechanism to achieving this. However, how these economic benefits are being translated into the change in women’s status, particularly their health status, remains unexplored and ultimately unaddressed. This working research paper attempts to review the scope and limitations of SHGs in improving women’s health and empowerment based upon empirical work undertaken in the Jharkhand state of India. Our paper also explores the extent to which SHGs can be involved in attaining better health status for women, and thereby point the way for further research. 

Contributions to Indian Economic Analysis: A Survey

Any survey of contributions to economic analysis in India, even though confined to the post-war years and to issues arising from domestic economic events and policy, runs into exceptional difficulties. Not only has practically every conceivable problem been raised and discussed by economists, in a country where interest in economic issues dates back at least to the latter half of the 19th century; but there have also been numerous committees and commissions whose report have led to a voluminous literature. Ruthless selectivity has thus been inevitable. We have generally focussed, in this survey, on contributions which meet the following criteria: (1) they should have analytical interest, either theoretical or empirical; (2) they should be made by Indian or India-based economists; and (3) they should have some bearing on Indian economic policy issues, even though they cannot necessarily be demonstrated to have arisen in consequence thereof or to have had any impact on policymaking. The Survey thus rules out of consideration the vast bulk of official literature, whose analytical base is frequently largely minimal, as also the purely descriptive and institutional material from non-official sources (such as the Indian Statistical Institute) whose utility otherwise is not to be minimized. Equally, the Survey does not extend to the growing numbers of contributions to general theoretical economic analysis that Indian economists have begun to make, as is evident from the contents of reputed journals in the last decade. This Survey, therefore, is neither a comprehensive account of the state of economic research in the country nor does it pretend to give an exhaustive picture of the policy issues that have been discussed on the Indian scene since 1947 when India gained independence

The Hyperfine Molecular Hubbard Hamiltonian

An ultracold gas of heteronuclear alkali dimer molecules with hyperfine structure loaded into a one-dimensional optical lattice is investigated. The \emph{Hyperfine Molecular Hubbard Hamiltonian} (HMHH), an effective low-energy lattice Hamiltonian, is derived from first principles. The large permanent electric dipole moment of these molecules gives rise to long range dipole-dipole forces in a DC electric field and allows for transitions between rotational states in an AC microwave field. Additionally, a strong magnetic field can be used to control the hyperfine degrees of freedom independently of the rotational degrees of freedom. By tuning the angle between the DC electric and magnetic fields and the strength of the AC field it is possible to control the number of internal states involved in the dynamics as well as the degree of correlation between the spatial and internal degrees of freedom. The HMHH's unique features have direct experimental consequences such as quantum dephasing, tunable complexity, and the dependence of the phase diagram on the molecular state

Decoupling of silicon carbide optical sensor response for temperature and pressure measurements (Erratum)

Single crystal silicon carbide is a chemically inert transparent material with superior oxidation-resistant properties at elevated temperatures compared to black polycrystalline silicon carbide substrates. These improved properties make crystalline silicon carbide a good optical sensor material for harsh environments such as combustion chambers and turbine systems. Interferometric optical sensors are orders of magnitude more sensitive than electrical sensors and are proposed for these applications. Silicon carbide itself behaves as a Fabry-Perot etalon eliminating the need for an external interferometer for any measurement using this silicon carbide as a sensor. The principle of the optical sensor in this study is the temperature- and pressure-dependent refractive index of silicon carbide, which can be used to determine the temperatures and pressures of gases that are in contact with silicon carbide. Interference patterns produced by a silicon carbide (4H-SiC) wafer due to multiple reflections of a helium-neon laser beam of wavelength of 632.8 nm have been obtained at temperatures up to 500 degrees C and pressures up to 600 psi. The pattern changes for the same gas at different temperatures and pressures and for different gases at the same temperature and pressure. The refractive index at the wafer-gas interface is calculated from the interference pattern and the refractive index gradients with respect to temperature and pressure, respectively, are also determined. Decoupling temperature and pressure using these gradients and the measured reflectivity data are discussed in this paper

Quantum-Critical Behavior in a Two-Layer Antiferromagnet

We analyze quantum Monte Carlo data in the vicinity of the quantum transition between a Neel state and a quantum paramagnet in a two-layer, square lattice spin 1/2 Heisenberg antiferromagnet. The real-space correlation function and the universal amplitude ratio of the structure factor and the dynamic susceptibility show clear evidence of quantum critical behavior at low temperatures. The numerical results are in good quantitative agreement with $1/N$ calculations for the $O(N)$ non-linear sigma model. A discrepancy, reported earlier, between the critical properties of the antiferromagnet and the sigma model is resolved. We also discuss the values of prefactors of the dynamic susceptibility and the structure factor in a single layer antiferromagnet at low $T$.Comment: 11 pages, REVtex file, 5 figures in a uuencoded, gziped file. One citation added