Proposal for an Experiment to Test a Theory of High Temperature Superconductors

A theory for the phenomena observed in Copper-Oxide based high temperature superconducting materials derives an elusive time-reversal and rotational symmetry breaking order parameter for the observed pseudogap phase ending at a quantum-critical point near the composition for the highest $T_c$. An experiment is proposed to observe such a symmetry breaking. It is shown that Angle-resolved Photoemission yields a current density which is different for left and right circularly polarized photons. The magnitude of the effect and its momentum dependence is estimated. Barring the presence of domains of the predicted phase an asymmetry of about 0.1 is predicted at low temperatures in moderately underdoped samples.Comment: latex, 2 figure

The Influence of Quantum Critical Fluctuations of Circulating Current Order Parameters on the Normal State Properties of Cuprates

We study a model of the quantum critical point of cuprates associated with the "circulating current" order parameter proposed by Varma. An effective action of the order parameter in the quantum disordered phase is derived using functional integral method, and the physical properties of the normal state are studied based on the action. The results derived within the ladder approximation indicate that the system is like Fermi liquid near the quantum critical point and in disordered regime up to minor corrections. This implies that the suggested marginal Fermi liquid behavior induced by the circulating current fluctuations will come in from beyond the ladder diagrams.Comment: 7pages, 1 figure included in RevTex file. To appear in Phys. Rev.

Theory of the Quantum Critical Fluctuations in Cuprates

The statistical mechanics of the time-reversal and inversion symmetry breaking order parameter, possibly observed in the pseudogap region of the phase diagram of the Cuprates, can be represented by the Ashkin-Teller model. We add kinetic energy and dissipation to the model for a quantum generalization and show that the correlations are determined by two sets of charges, one interacting locally in time and logarithmically in space and the other locally in space and logarithmically in time. The quantum critical fluctuations are derived and shown to be of the form postulated in 1989 to give the marginal fermi-liquid properties. The model solved and the methods devised are likely to be of interest also to other quantum phase transitions

Excitonic Instability and Origin of the Mid-Gap States

In the framework of the two-band model of a doped semiconductor the self-consistent equations describing the transition into the excitonic insulator state are obtained for the 2D case. It is found that due to the exciton-electron interactions the excitonic phase may arise with doping in a semiconductor stable initially with respect to excitonic transition in the absence of doping. The effects of the strong interactions between electron (hole) Fermi-liquid (FL) and excitonic subsystems can lead to the appearance of the states lying in the middle of the insulating gap.Comment: 2 pages with 2 figures available upon request, LaTex Version 3.0 (PCTeX), to appear in the Proceedings of the M2S-HTSC IV Conferenc

100% Solid Polyurethane the Innovative Technology for Corrosion Protection

100% solid polyurethane is the latest innovation in the field of anti corrosive coatings. It is internationally recognised for providing highest degree of protection to vital installations such as oil & gas pipelines, tanks, LPG mounded bullets and structures exposed to aggressi-vely corrosive environment encountered in buried underground conditions or exposed to seawater such as drilling platforms, coastal installations or plant and equipment in sewage / waste water treatment services. 100% solid polyurethane is a two component, solvent free, elastomeric, thermosetting coating compound, which is expected to preserve the integrity of structures over their design life. It is preferred over other traditional coating systems because of its outstanding life expec-tancy, resistance to aggressively corrosive environment, very high abrasion and impact resistance, strong adhesion to steel substrate, extremely fast curing capability, high film build characteristic and most importantly, compliance with rigorous regulations on volatile organic compound (VOC) emissions. In India, the concept of 100% solid polyurethane coating has come in only recently. Major oil and gas companies and reputed engineering consultants are now recommending its use to protect critical installations such as LPG moun-ded bullets, rehabilitation of old pipelines where conven-tional coating have failed, field joint of cross country pipelines, internal linings of intake water pipelines in power plants, equipment employed in waste water treatment plants etc. This paper discusses in depth the chemistry of 100% solid polyurethane, its properties & physical characteri-stics, equipment and application techniques as also its various advantages

Indian Diaspora: Analysis Of Its Advantage To The Home Country And To The World

Migration has been a common phenomenon since a long time. Movement of people across borders and thus, movement of ideas, new skills and technical know-how result in the benefits not only for the receiving countries but also for the sending countries. In this regard, it is very important to consider the role of Diaspora communities for the receiving countries and our study focuses on the role of Indian Diaspora communities residing in other foreign lands and will analyze their roles in enhancing the working of different sectors of the economy in which they live. The study further illuminates the contribution of the Indian Diaspora to their native land i.e., India. There is no denial to the fact that Indian Diaspora has been contributing towards the development of the Indian economy in being the major source of Foreign Direct Investment, in transferring technology and technical know- how, substantial flow of knowledge, contributing towards tourism, charity activities, in establishing NGOs to work towards the betterment of the society and fighting social evils existing. The othersideofthisphenomenonisthe contribution of Indian Diaspora to the receiving countries, basically, to those countries in which they live. These communities bring in their skills for the utilization of the available resources, put on their knowledge and add onto the set of technical know- how, providing new demand to the consumer market, providing to the employment opportunities and also adding to the production level of the economy. So this paper reveals the positive aspect of the existing of Indian Diasporaforforeigncountries,relating their advantages to Indian Territory also

A comprehensive study of electric, thermoelectric and thermal conductivities of Graphene with short range unitary and charged impurities

Motivated by the experimental measurement of electrical and hall conductivity, thermopower and Nernst effect, we calculate the longitudinal and transverse electrical and heat transport in graphene in the presence of unitary scatterers as well as charged impurities. The temperature and carrier density dependence in this system display a number of anomalous features that arise due to the relativistic nature of the low energy fermionic degrees of freedom. We derive the properties in detail including the effect of unitary and charged impurities self-consistently, and present tables giving the analytic expressions for all the transport properties in the limit of small and large temperature compared to the chemical potential and the scattering rates. We compare our results with the available experimental data. While the qualitative variations with temperature and density of carriers or chemical potential of all transport properties can be reproduced, we find that a given set of parameters of the impurities fits the Hall conductivity, Thermopower and the Nernst effect quantitatively but cannot fit the conductivity quantitatively. On the other hand a single set of parameters for scattering from Coulomb impurities fits conductivity, hall resistance and thermopower but not Nernst