763 research outputs found

    Fermi distribution of semicalssical non-eqilibrium Fermi states

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    When a classical device suddenly perturbs a degenerate Fermi gas a semiclassical non-equilibrium Fermi state arises. Semiclassical Fermi states are characterized by a Fermi energy or Fermi momentum that slowly depends on space or/and time. We show that the Fermi distribution of a semiclassical Fermi state has a universal nature. It is described by Airy functions regardless of the details of the perturbation. In this letter we also give a general discussion of coherent Fermi states

    Raman Scattering and Anomalous Current Algebra: Observation of Chiral Bound State in Mott Insulators

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    Recent experiments on inelastic light scattering in a number of insulating cuprates [1] revealed a new excitation appearing in the case of crossed polarizations just below the optical absorption threshold. This observation suggests that there exists a local exciton-like state with an odd parity with respect to a spatial reflection. We present the theory of high energy large shift Raman scattering in Mott insulators and interpret the experiment [1] as an evidence of a chiral bound state of a hole and a doubly occupied site with a topological magnetic excitation. A formation of these composites is a crucial feature of various topological mechanisms of superconductivity. We show that inelastic light scattering provides an instrument for direct measurements of a local chirality and anomalous terms in the electronic current algebra.Comment: 18 pages, TeX, C Version 3.

    Berezinskii-Kosterlitz-Thouless transitions in the six-state clock model

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    Classical 2D clock model is known to have a critical phase with Berezinskii-Kosterlitz-Thouless(BKT) transitions. These transitions have logarithmic corrections which make numerical analysis difficult. In order to resolve this difficulty, one of the authors has proposed the method called level spectroscopy, which is based on the conformal field theory. We extend this method to the multi-degenerated case. As an example, we study the classical 2D 6-clock model which can be mapped to the quantum self-dual 1D 6-clock model. Additionally, we confirm that the self-dual point has a precise numerical agreement with the analytical result, and we argue the degeneracy of the excitation states at the self-dual point from the effective field theoretical point of view.Comment: 18pages, 7figure

    2D String Theory as Normal Matrix Model

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    We show that the c=1c=1 bosonic string theory at finite temperature has two matrix-model realizations related by a kind of duality transformation. The first realization is the standard one given by the compactified matrix quantum mechanics in the inverted oscillator potential. The second realization, which we derive here, is given by the normal matrix model. Both matrix models exhibit the Toda integrable structure and are associated with two dual cycles (a compact and a non-compact one) of a complex curve with the topology of a sphere with two punctures. The equivalence of the two matrix models holds for an arbitrary tachyon perturbation and in all orders in the string coupling constant.Comment: lanlmac, 21 page

    The cancellation of worldsheet anomalies in the D=10 Green--Schwarz heterotic string sigma--model

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    We determine the two--dimensional Weyl, Lorentz and κ\kappa--anomalies in the D=10D=10 Green--Schwarz heterotic string sigma--model, in an SO(1,9)SO(1,9)-Lorentz covariant background gauge, and prove their cancellation.Comment: 12 pages, Plain TeX, no figure

    Integrability in SFT and new representation of KP tau-function

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    We are investigating the properties of vacuum and boundary states in the CFT of free bosons under the conformal transformation. We show that transformed vacuum (boundary state) is given in terms of tau-functions of dispersionless KP (Toda) hierarchies. Applications of this approach to string field theory is considered. We recognize in Neumann coefficients the matrix of second derivatives of tau-function of dispersionless KP and identify surface states with the conformally transformed vacuum of free field theory.Comment: 25 pp, LaTeX, reference added in the Section 3.

    Cluster Algorithms for Quantum Impurity Models and Mesoscopic Kondo Physics

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    Nanoscale physics and dynamical mean field theory have both generated increased interest in complex quantum impurity problems and so have focused attention on the need for flexible quantum impurity solvers. Here we demonstrate that the mapping of single quantum impurity problems onto spin-chains can be exploited to yield a powerful and extremely flexible impurity solver. We implement this cluster algorithm explicitly for the Anderson and Kondo Hamiltonians, and illustrate its use in the ``mesoscopic Kondo problem''. To study universal Kondo physics, a large ratio between the effective bandwidth DeffD_\mathrm{eff} and the temperature TT is required; our cluster algorithm treats the mesoscopic fluctuations exactly while being able to approach the large Deff/TD_\mathrm{eff}/T limit with ease. We emphasize that the flexibility of our method allows it to tackle a wide variety of quantum impurity problems; thus, it may also be relevant to the dynamical mean field theory of lattice problems.Comment: 4 pages, 3 figure

    Carbohydrate Catabolism in Phaeobacter inhibens DSM 17395, a Member of the Marine Roseobacter Clade

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    Since genome analysis did not allow unambiguous reconstruction of transport, catabolism, and substrate-specific regulation for several important carbohydrates in Phaeobacter inhibens DSM 17395, proteomic and metabolomic analyses of N-acetylglucosamine-, mannitol-, sucrose-, glucose-, and xylose-grown cells were carried out to close this knowledge gap. These carbohydrates can pass through the outer membrane via porins identified in the outer membrane fraction. For transport across the cytoplasmic membrane, carbohydrate-specific ABC transport systems were identified. Their coding genes mostly colocalize with the respective "catabolic" and "regulatory" genes. The degradation of N-acetylglucosamine proceeds via N-acetylglucosamine-6-phosphate and glucosamine-6-phosphate directly to fructose-6-phosphate; two of the three enzymes involved were newly predicted and identified. Mannitol is catabolized via fructose, sucrose via fructose and glucose, glucose via glucose-6-phosphate, and xylose via xylulose-5-phosphate. Of the 30 proteins predicted to be involved in uptake, regulation, and degradation, 28 were identified by proteomics and 19 were assigned to their respective functions for the first time. The peripheral degradation pathways feed into the Entner-Doudoroff (ED) pathway, which is connected to the lower branch of the Embden-Meyerhof-Parnas (EMP) pathway. The enzyme constituents of these pathways displayed higher abundances in P. inhibens DSM 17395 cells grown with any of the five carbohydrates tested than in succinate-grown cells. Conversely, gluconeogenesis is turned on during succinate utilization. While tricarboxylic acid (TCA) cycle proteins remained mainly unchanged, the abundance profiles of their metabolites reflected the differing growth rates achieved with the different substrates tested. Homologs of the 74 genes involved in the reconstructed catabolic pathways and central metabolism are present in various Roseobacter clade members

    Edge scaling limits for a family of non-Hermitian random matrix ensembles

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    A family of random matrix ensembles interpolating between the GUE and the Ginibre ensemble of n×nn\times n matrices with iid centered complex Gaussian entries is considered. The asymptotic spectral distribution in these models is uniform in an ellipse in the complex plane, which collapses to an interval of the real line as the degree of non-Hermiticity diminishes. Scaling limit theorems are proven for the eigenvalue point process at the rightmost edge of the spectrum, and it is shown that a non-trivial transition occurs between Poisson and Airy point process statistics when the ratio of the axes of the supporting ellipse is of order n1/3n^{-1/3}. In this regime, the family of limiting probability distributions of the maximum of the real parts of the eigenvalues interpolates between the Gumbel and Tracy-Widom distributions.Comment: 44 page
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