3,983 research outputs found

    Fermions at unitarity and Haldane Exclusion Statistics

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    We consider a gas of neutral fermionic atoms at ultra-low temperatures, with the attractive interaction tuned to Feshbach resonance. We calculate, the variation of the chemical potential and the energy per particle as a function of temperature by assuming the system to be an ideal gas obeying the Haldane-Wu fractional exclusion statistics. Our results for the untrapped gas compare favourably with the recently published Monte Carlo calculations of two groups. For a harmonically trapped gas, the results agree with experiment, and also with other published work.Comment: 4 pages, 1 postscript figur

    Electronic Theses and Dissertations and Academia: A Preliminary Study From India

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    This paper outlines the current state of doctoral theses collections in India, their usage, problems with access, and the academic and research community’s attitude towards digital archiving and electronic publishing in Indian universities

    Electronic Theses and Dissertations and Academia: A Preliminary Study From India

    Get PDF
    This paper outlines the current state of doctoral theses collections in India, their usage, problems with access, and the academic and research community’s attitude towards digital archiving and electronic publishing in Indian universities

    D-branes in Unoriented Non-critical Strings and Duality in SO(N) and Sp(N) Gauge Theories

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    We exhibit exact conformal field theory descriptions of SO(N) and Sp(N) pairs of Seiberg-dual gauge theories within string theory. The N=1 gauge theories with flavour are realized as low energy limits of the worldvolume theories on D-branes in unoriented non-critical superstring backgrounds. These unoriented backgrounds are obtained by constructing exact crosscap states in the SL(2,R)/U(1) coset conformal field theory using the modular bootstrap method. Seiberg duality is understood by studying the behaviour of the boundary and crosscap states under monodromy in the closed string parameter space.Comment: 23 pages, 2 figure

    Critical Crossover Between Yosida-Kondo Dominant Regime and Magnetic Frustration Dominant Regime in the System of a Magnetic Trimer on a Metal Surface

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    Quantum Monte Carlo simulations were carried out for the system of a magnetic trimer on a metal surface. The magnetic trimer is arranged in two geometric configurations, viz., isosceles and equilateral triangles. The calculated spectral density and magnetic susceptibility show the existence of two phases: Yosida-Kondo dominant phase and magnetic frustration dominant phase. Furthermore, a critical transition between these two phases can be induced by changing the configuration of the magnetic trimers from isosceles to equilateral triangle.Comment: 8 pages, 4 figures; accepted for publication in J. Phys. Soc. Jp

    Exactly solvable toy models of unconventional magnetic alloys: Bethe Ansatz versus Renormalization Group method

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    We propose toy models of unconventional magnetic alloys, in which the density of band states, ρ(ϵ)\rho(\epsilon), and hybridization, t(ϵ)t(\epsilon), are energy dependent; it is assumed, however, that t2(ϵ)ρ1(ϵ)t^2(\epsilon)\propto\rho^{-1}(\epsilon), and hence an effective electron-impurity coupling Γ(ϵ)=ρ(ϵ)t2(ϵ)\Gamma(\epsilon)=\rho(\epsilon)t^2(\epsilon) is energy independent. In the renormalization group approach, the physics of the system is assumed to be governed by Γ(ϵ)\Gamma(\epsilon) only rather than by separate forms of ρ(ϵ)\rho(\epsilon) and t(ϵ)t(\epsilon). However, an exact Bethe Ansatz solution of the toy Anderson model demonstrates a crucial role of a form of inverse band dispersion k(ϵ)k(\epsilon).Comment: A final version. A previous one has been sent to Archive because of my technical mistake. Sorr

    Theory of the Half-Polarized Quantum Hall States

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    We report a theoretical analysis of the half-polarized quantum Hall states observed in a recent experiment. Our numerical results indicate that the ground state energy of the quantum Hall ν=2/3\nu= 2/3 and ν=2/5\nu= 2/5 states versus spin polarization has a downward cusp at half the maximal spin polarization. We map the two-component fermion system onto a system of excitons and describe the ground state as a liquid state of excitons with non-zero values of exciton angular momentum.Comment: 4 pages (RevTeX), 3 figures (PostScript), added reference

    Topological Cigar and the c=1 String : Open and Closed

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    We clarify some aspects of the map between the c=1 string theory at self-dual radius and the topologically twisted cigar at level one. We map the ZZ and FZZT D-branes in the c=1 string theory at self dual radius to the localized and extended branes in the topological theory on the cigar. We show that the open string spectrum on the branes in the two theories are in correspondence with each other, and their two point correlators are equal. We also find a representation of an extended N=2 algebra on the worldsheet which incorporates higher spin currents in terms of asymptotic variables on the cigar.Comment: 37 pages, 2 figures, corrections to section 3.1, references adde

    Economic Analysis of Post-Harvest Loss and Marketing Efficiency in Guava (cv. Allahabad safeda) in Karnataka

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    Post-harvest losses (PHL) in guava (cv. Allahabad safeda) were estimated at the field and retail levels in Karnataka, and impact of this loss on marketing efficiency was studied. Results indicated that the total PHL was 13.29% consisting of field-level loss (9.17%) and retail level loss (4.12%). The producer's share was 51.52% and PHL, when included as an item of cost, reduced the share to 45.80%. PHL also reduced marketing efficiency index from 1.06 to 0.88, thereby indicating the importance of PHL and scope for minimizing it to improve the efficiency of the marketing system in guava

    Classical Many-particle Clusters in Two Dimensions

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    We report on a study of a classical, finite system of confined particles in two dimensions with a two-body repulsive interaction. We first develop a simple analytical method to obtain equilibrium configurations and energies for few particles. When the confinement is harmonic, we prove that the first transition from a single shell occurs when the number of particles changes from five to six. The shell structure in the case of an arbitrary number of particles is shown to be independent of the strength of the interaction but dependent only on its functional form. It is also independent of the magnetic field strength when included. We further study the effect of the functional form of the confinement potential on the shell structure. Finally we report some interesting results when a three-body interaction is included, albeit in a particular model.Comment: Minor corrections, a few references added. To appear in J. Phys: Condensed Matte
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