9,065 research outputs found

    Effective Gap Equation for the Inhomogeneous LOFF Superconductive Phase

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    We present an approximate gap equation for different crystalline structures of the LOFF phase of high density QCD at T=0. This equation is derived by using an effective condensate term obtained by averaging the inhomogeneous condensate over distances of the order of the crystal lattice size. The approximation is expected to work better far off any second order phase transition. As a function of the difference of the chemical potentials of the up and down quarks, δμ\delta\mu, we get that the octahedron is energetically favored from δμ=Δ0/2\delta\mu=\Delta_0/\sqrt 2 to 0.95Δ00.95\Delta_0, where Δ0\Delta_0 is the gap for the homogeneous phase, while in the range 0.95Δ01.32Δ00.95\Delta_0-1.32\Delta_0 the face centered cube prevails. At δμ=1.32Δ0\delta\mu=1.32\Delta_0 a first order phase transition to the normal phase occurs.Comment: 11 pages, 5 figure

    Chiral Loops and Ghost States in the Quenched Scalar Propagator

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    The scalar, isovector meson propagator is analyzed in quenched QCD, using the MQA pole-shifting ansatz to study the chiral limit. In addition to the expected short-range exponential falloff characteristic of a heavy scalar meson, the propagator also exhibits a longer-range, negative metric contribution which becomes pronounced for smaller quark masses. We show that this is a quenched chiral loop effect associated with the anomalous structure of the η\eta ' propagator in quenched QCD. Both the time dependence and the quark mass dependence of this effect are well-described by a chiral loop diagram corresponding to an ηπ\eta '- \pi intermediate state, which is light and effectively of negative norm in the quenched approximation. The relevant parameters of the effective Lagrangian describing the scalar sector of the quenched theory are determined.Comment: 29 pages, 10 figures, Late

    Neutrino processes in the K0K^0 condensed phase of color flavor locked quark matter

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    We study weak interactions involving Goldstone bosons in the neutral kaon condensed phase of color flavor locked quark matter. We calculate the rates for the dominant processes that contribute to the neutrino mean free p ath and to neutrino production. A light K+K^+ state, with a mass m~K+(Δ/μ)(Δ/ms)(mdmu)\tilde{m}_{K^+} \propto (\Delta/\mu) (\Delta/m_s)(m_d-m_u), where μ\mu and Δ\Delta are the quark chemical potential and superconducting gap respectively, is shown to play an important role. We identify unique characteristics of weak interaction rates in this novel phase and discuss how they might influence neutrino emission in core collapse supernova and neutron stars.Comment: 21 pages, 4 figure

    The Ginzburg-Landau Free Energy Functional of Color Superconductivity at Weak Coupling

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    We derive the Ginzburg-Landau free energy functional of color superconductivity in terms of the thermal diagrams of QCD in its perturbative region. The zero mode of the quadratic term coefficient yields the same transition temperature, including the pre-exponential factor, as the one obtained previously from the Fredholm determinant of the two quark scattering amplitude. All coefficients of the free energy can be made identical to those of a BCS model by setting the Fermi velocity of the latter equal to the speed of light. We also calculate the induced symmetric color condensate near TcT_c and find that it scales as the cubic power of the dominant antisymmetric color component. We show that in the presence of an inhomogeneity and a nonzero gauge potential, while the color-flavor locked condensate dominates in the bulk, the unlocked condensate, the octet, emerges as a result of a simultaneous color-flavor rotation in the core region of a vortex filament or at the junction of super and normal phases.Comment: 32 pages, Plain Tex, 3 figure

    Self-dual Yang-Mills fields in pseudoeuclidean spaces

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    The self-duality Yang-Mills equations in pseudoeuclidean spaces of dimensions d8d\leq 8 are investigated. New classes of solutions of the equations are found. Extended solutions to the D=10, N=1 supergravity and super Yang-Mills equations are constructed from these solutions.Comment: 9 pages, LaTeX, no figure

    On highest-energy state in the su(1|1) sector of N=4 super Yang-Mills theory

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    We consider the highest-energy state in the su(1|1) sector of N=4 super Yang-Mills theory containing operators of the form tr(Z^{L-M} \psi^M) where Z is a complex scalar and \psi is a component of gaugino. We show that this state corresponds to the operator tr(\psi^L) and can be viewed as an analogue of the antiferromagnetic state in the su(2) sector. We find perturbative expansions of the energy of this state in both weak and strong 't Hooft coupling regimes using asymptotic gauge theory Bethe ansatz equations. We also discuss a possible analog of this state in the conjectured string Bethe ansatz equations.Comment: 23 pages, Late

    Reduced sigma-model on AdS_5 x S^5: one-loop scattering amplitudes

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    We compute one-loop S-matrix in the reduced sigma-model which describes AdS_5 x S^5 string theory in the near-flat-space limit. The result agrees with the corresponding limit of the S-matrix in the full sigma-model, which demonstrates the consistency of the reduction at the quantum level.Comment: 9 pages, 1 figure; v2: reference added; v3: misprint in (3.6) corrected; v4: typo in (3.4) corrected; v5: new form of the actio
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