36,399 research outputs found

    Vacuum structure and effective potential at finite temperature: a variational approach

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    We compute the effective potential for Ōē4\phi^4 theory with a squeezed coherent state type of construct for the ground state. The method essentially consists in optimising the basis at zero and finite temperatures. The gap equation becomes identical to resumming the infinite series of daisy and super daisy graphs while the effective potential includes multiloop effects and agrees with that obtained through composite operator formalism at finite temperature.Comment: 15 pages, Revtex, No figures, to appear in Jou. of Phys.G(Nucl. and Part. Phys.

    A Variational Approach to Bound States in Quantum Field Theory

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    We consider here in a toy model an approach to bound state problem in a nonperturbative manner using equal time algebra for the interacting field operators. Potential is replaced by offshell bosonic quanta inside the bound state of nonrelativistic particles. The bosonic dressing is determined through energy minimisation, and mass renormalisation is carried out in a nonperturbative manner. Since the interaction is through a scalar field, it does not include spin effects. The model however nicely incorporates an intuitive picture of hadronic bound states in which the gluon fields dress the quarks providing the binding between them and also simulate the gluonic content of hadrons in deep inelastic collisions.Comment: latex, revtex, 22 page

    Spin-Charge Decoupling and Orthofermi Quantum Statistics

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    Currently Gutzwiller projection technique and nested Bethe ansatz are two main methods used to handle electronic systems in the UU infinity limit. We demonstrate that these two approaches describe two distinct physical systems. In the nested Bethe ansatz solutions, there is a decoupling between the spin and charge degrees of freedom. Such a decoupling is absent in the Gutzwiller projection technique. Whereas in the Gutzwiller approach, the usual antisymmetry of space and spin coordinates is maintained, we show that the Bethe ansatz wave function is compatible with a new form of quantum statistics, viz., orthofermi statistics. In this statistics, the wave function is antisymmetric in spatial coordinates alone. This feature ultimately leads to spin-charge decoupling.Comment: 12 pages, LaTex Journal_ref: A slightly abridged version of this paper has appeared as a brief report in Phys. Rev. B, Vol. 63, 132405 (2001

    An Assessment of Knowledge and Practices Regarding Tuberculosis in the Context of RNTCP Among Non Allopathic Practitioners in Gwalior District

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    Introduction: India has the highest TB burden accounting for one-fifth of the global incidence with an estimated 1.98 million cases. Non- allopathic practitioners are the major service providers especially in rural and peri-urban areas, treating not just patients of diarrhea, respiratory infections and abdominal Pain but also of tuberculosis. Objectives: To assess the knowledge of sign and symptoms of TB and its management as per the RNTCP guidelines and to assess the practicing pattern regarding tuberculosis. Material & Methods: The present was carried out among the registered non allopathic practitioners providing their services in Gwalior District during the study period. A total of 150 non allopathic practitioners of various methods from both government and private sectors were interviewed using a pre-designed, pre-tested semi-structured questionnaire. The information was collected on the General profile of the participant, knowledge about signs and symptoms of TB and its management, practices commonly adopted in the management and their views on involvement of non allopathic practitioners in RNTCP programme. Result: The average score of government practitioners was 7.3 compared to 4.6 by private practitioners. There was a statistically significant difference between the two group on issue related to the management of TB patients as per the RNTCP guidelines. Government practitioners relied mostly on sputum examination for diagnosis and follow up compared to private practitioners who chose other modalities like X-ray, blood examination for this work. Conclusion: There is a gap in knowledge and practices of practitioners of both the sectors. Some serious efforts were required to upgrade the knowledge of non allopathic practitioners if the government is serious about controlling tuberculosis in India

    Color superconducting 2SC+s quark matter and gapless modes at finite temperatures

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    We investigate the phase diagram of color superconducting quark matter with strange quarks (2SC+s quark matter) in beta equliibrium at zero as well as finite temperatures within a Nambu-Jona-Lasinio model. The variational method as used here allows us to investigate simultaneous formation of condensates in quark--antiquark as well as in diquark channels. Color and electric charge neutrality conditions are imposed in the calculation of the thermodynamic potential. Medium dependance of strange quark mass plays a sensitve role in maintaining charge neutrality conditions. At zero temperature the system goes from gapless phase to usual BCS phase through an intermediate normal phase as density is increased. The gapless modes show a smooth behaviour with respect to temperature vanishing above a critical temperature which is larger than the BCS transition temperature. We observe a sharp transition from gapless superconducting phase to the BCS phase as density is increased for the color neutral matter at zero temperature. As temperature is increased this however becomes a smooth transition.Comment: 18 pages, 14 figure

    Chiral Symmetry Breaking and Pion Wave Function

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    We consider here chiral symmetry breaking through nontrivial vacuum structure with quark antiquark condensates. We then relate the condensate function to the wave function of pion as a Goldstone mode. This simultaneously yields the pion also as a quark antiquark bound state as a localised zero mode in vacuum. We illustrate the above with Nambu Jona-Lasinio model to calculate different pionic properties in terms of the vacuum structure for breaking of exact or approximate chiral symmetry, as well as the condensate fluctuations giving rise to ŌÉ\sigma mesons.Comment: latex, revtex, 16 page
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