1,718 research outputs found

    Interacting fermions in two dimension in simultaneous presence of disorder and magnetic field

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    We have studied the revival of Hofstadter butterfly due to the competition between disorder and electronic interaction using mean field approximation of unrestricted Hartree Fock method at zero temperature for two dimensional square and honeycomb lattices. Interplay of disorder and electronic correlation to nullify each other is corroborated by the fact that honeycomb lattice needs more strength of electronic correlation owing to its less co-ordination number which enhances the effect of disorder. The extent of revival of the butterfly is better in square than honeycomb lattice due to higher coordination number. The effect of disorder and interaction is also investigated to study entanglement entropy and entanglement spectrum. It has been observed that for the square lattice, area law of entanglement entropy is violated for intermediate strength magnetic and magnitude of such departure from area law depends on disorder and interaction as well. However such departure from area law is absence for honeycomb lattice. Moreover the entanglement spectrum for square lattice does have the symmetry of original Hofstadter butterfly and this symmetry is destroyed in the presence of disorder. The interaction opens up a gap in the entanglement spectrum as well. For the honeycomb lattice, the entanglement spectrum forms a continuous band without any symmetry and its feature is mostly unchanged in the presence of disorder as well as interaction

    GLYCATED HEMOGLOBIN LEVELS IN METABOLIC SYNDROME PATIENTS

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    Objectives: Metabolic syndrome (MetS) is a cluster of several metabolic disorders including hyperglycemia, reduced high-density lipoprotein cholesterol, and raised triglyceride level in serum, hypertension, and abdominal obesity. Glycated hemoglobin (HbA1c) is used as one of the diagnostic criteria for diabetes and diagnostic tool for MetS. Methods: The present study was conducted at Prasad Institute of Medical Sciences. The study includes 150 patients with MetS as a case and 150 healthy volunteers as a control. MetS was diagnosed according to National Cholesterol Education Program’s Adult Treatment Panel III criteria. HbA1c was assayed in various components of MetS. Results: It was found that HbA1c was significantly higher in MetS patients when compared to control group. Conclusion: Our study suggests that HbA1c might be used as a diagnostic criterion for MetS. Therefore, proper glycemic control should be maintained by maintaining HbA1c level <6.5% to prevent from diabetes and MetS

    Observational constraints and some toy models in f(Q)f(Q) gravity with bulk viscous fluid

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    The standard formulation of general relativity fails to describe some recent interests in the universe. It impels us to go beyond the standard formulation of gravity. The f(Q)f(Q) gravity theory is an interesting modified theory of gravity, where the gravitational interaction is driven by the nonmetricity QQ. This study aims to examine the cosmological models with the presence of bulk viscosity effect in the cosmological fluid within the framework of f(Q)f(Q) gravity. We construct three bulk viscous fluid models, i.e. (i) for the first model, we assuming the Lagrangian f(Q)f(Q) as linear dependence on QQ, (ii) for the second model the Lagrangian f(Q)f(Q) as a polynomial functional form, and (iii) the Lagrangian f(Q)f(Q) as a logarithmic dependence on QQ. Furthermore, we use 57 points of Hubble data and 1048 Pantheon dataset to constraint the model parameters. Then, we discuss all the energy conditions for each model, which helps us to test the self-consistency of our models. Finally, we present the profiles of the equation of state parameters to test the models' present status.Comment: 13 pages,9 figures. Comments are Welcom

    Gravastar in the Framework of Symmetric Teleparallel Gravity

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    In the current research, we present a novel gravastar model based on the Mazur-Mottola (2004) method with an isotropic matter distribution in f(Q)f(Q) gravity. The gravastar, a hypothesized substitute for a black hole, is built using the Mazur-Mottola mechanism. This approach allows us to define gravastar as having three stages. The first one is an inner region with negative pressure; the next region is a thin shell that is made up of ultrarelativistic stiff fluid, we have studied proper length, energy, entropy, and surface energy density for this region. Apart from that, we have demonstrated the possible stability of our suggested thin shell gravastar model through the graphical study of surface redshift. Exterior Schwarzschild geometry describes the outer region of the gravastar. In the context of f(Q)f(Q) gravity, we have discovered analytical solutions for the interior of gravastars that are free of any kind of singularity and the event horizon.Comment: Chinese Physics C published versio

    Slow-roll inflation in f(T,T)f(T,\mathcal{T}) modified gravity

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    In this article, we explore the concept of cosmological inflation within the framework of the f(T,T)f (T,\mathcal{T}) theory of gravity, where ff is a general function of the Torsion scalar TT and the trace, T\mathcal{T}, of the energy-momentum tensor. It is assumed that the conditions of slow-roll inflation are applicable inf(T,T)f (T,\mathcal{T}) gravity. To determine different observables related to inflation, such as the tensor-to-scalar ratio rr, scalar spectral index nsn_s, spectral index αs \alpha_s , and tensor spectral index ntn_t, the Hubble slow-roll parameters are utilized for a particular model of f(T,T)f (T,\mathcal{T}). Lastly, an assessment has been carried out to determine the feasibility of the models by conducting a numerical analysis of the parameters. The findings indicate that it is feasible to achieve compatibility with the observational measurements of slow-roll parameters by utilizing different values of the free parameters.Comment: Chinese Physics C published versio

    Seismic stability of reinforced-soil wall by pseudo-dynamic method

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    Determination of the internal stability of reinforced soil walls under earthquake conditions is an important part of seismic design. The horizontal method of slices is used for determining internal stability or for tieback analysis of the reinforced soil wall. A pseudo-dynamic method is adopted in the present analysis, which considers the effect of phase difference in both the shear and primary waves travelling through the backfill due to seismic excitation. Reinforced soil walls with cohesionless backfill material have been considered in the analysis. Results are presented in graphical and tabular form to show the required tensile force and length of geosynthetic reinforcement to maintain the stability of the reinforced soil wall under seismic conditions. The effects of variation of parameters such as soil friction angle and horizontal and vertical seismic accelerations on the stability of the reinforced soil wall have been studied. With an increase of seismic accelerations in both the horizontal and vertical directions the stability of the reinforced soil wall decreases significantly, and thus greater strength and length of the geosynthetic reinforcement are required to maintain stability of the wall. The seismic vertical acceleration in an upward direction gives higher values of the required geosynthetic tensile strength, and the seismic vertical acceleration in the downward direction yields higher values of the length of geosynthetic reinforcement. Comparisons of the present results with available pseudo-static results are shown, and the limitations of the pseudo-static results are highlighted
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