217 research outputs found

    The chromatographic identification of some biologically important phosphate esters

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    the objective of the present work was to provide a means for separating and indentifying phosphate esters involved in glycolysis in higher plants. Paper chromatography of phosphate esters has been employed by several workers, most notably Benson et al. (1) and Hanes and Isherwood (2). Benson's procedures were not primarily designed for identification of phosphate esters and gave low Rr values for the phosphate compounds of particular interest to us. The unidimensional methods of Hanes and Isherwood do not result in adequate resolution of the complex mixtures such as are obtained from our plant materials. The present procedure is based on two-dimensional chromatography with successive development in an acid and in a basic solvent. The solvents finally selected gave the best over-all resolution of the intermediates involved in plant glycolysis. Undoubtedly the resolution of certain pairs of compounds may be improved by suitable modifications. We have in addition made certain improvements in the procedure for locating the chromatographed materials

    Elliptic Wess-Zumino-Witten Model from Elliptic Chern-Simons Theory

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    This letter continues the program aimed at analysis of the scalar product of states in the Chern-Simons theory. It treats the elliptic case with group SU(2). The formal scalar product is expressed as a multiple finite dimensional integral which, if convergent for every state, provides the space of states with a Hilbert space structure. The convergence is checked for states with a single Wilson line where the integral expressions encode the Bethe-Ansatz solutions of the Lame equation. In relation to the Wess-Zumino-Witten conformal field theory, the scalar product renders unitary the Knizhnik-Zamolodchikov-Bernard connection and gives a pairing between conformal blocks used to obtain the genus one correlation functions.Comment: 18 pages, late

    On the deconfining limit in (2+1)-dimensional Yang-Mills theory

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    We consider (2+1)-dimensional Yang-Mills theory on S1×S1×RS^1 \times S^1 \times {\bf R} in the framework of a Hamiltonian approach developed by Karabali, Kim and Nair. The deconfining limit in the theory can be discussed in terms of one of the S1S^1 radii of the torus (S1×S1S^1 \times S^1), while the other radius goes to infinity. We find that the limit agrees with the previously known result for a dynamical propagator mass of a gluon. We also make comparisons with numerical data.Comment: 21 pages; v2. lattice data references updated, comparative statements revised; v3. minor corrections; v4. section 6 extended, published versio

    Combinatorial quantization of the Hamiltonian Chern-Simons theory I

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    Motivated by a recent paper of Fock and Rosly \cite{FoRo} we describe a mathematically precise quantization of the Hamiltonian Chern-Simons theory. We introduce the Chern-Simons theory on the lattice which is expected to reproduce the results of the continuous theory exactly. The lattice model enjoys the symmetry with respect to a quantum gauge group. Using this fact we construct the algebra of observables of the Hamiltonian Chern-Simons theory equipped with a *-operation and a positive inner product.Comment: 49 pages. Some minor corrections, discussion of positivity improved, a number of remarks and a reference added

    Chern-Simons States at Genus One

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    We present a rigorous analysis of the Schr\"{o}dinger picture quantization for the SU(2)SU(2) Chern-Simons theory on 3-manifold torus×\timesline, with insertions of Wilson lines. The quantum states, defined as gauge covariant holomorphic functionals of smooth su(2)su(2)-connections on the torus, are expressed by degree 2k2k theta-functions satisfying additional conditions. The conditions are obtained by splitting the space of semistable su(2)su(2)-connections into nine submanifolds and by analyzing the behavior of states at four codimension 11 strata. We construct the Knizhnik-Zamolodchikov-Bernard connection allowing to compare the states for different complex structures of the torus and different positions of the Wilson lines. By letting two Wilson lines come together, we prove a recursion relation for the dimensions of the spaces of states which, together with the (unproven) absence of states for spins\s>{_1\over^2}level implies the Verlinde dimension formula.Comment: 33 pages, IHES/P

    Chern-Simons theory and BCS superconductivity

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    We study the relationship between the holomorphic unitary connection of Chern-Simons theory with temporal Wilson lines and the Richardson's exact solution of the reduced BCS Hamiltonian. We derive the integrals of motion of the BCS model, their eigenvalues and eigenvectors as a limiting case of the Chern-Simons theory.Comment: 23 page

    SU(2) WZW Theory at Higher Genera

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    We compute, by free field techniques, the scalar product of the SU(2) Chern-Simons states on genus > 1 surfaces. The result is a finite-dimensional integral over positions of ``screening charges'' and one complex modular parameter. It uses an effective description of the CS states closely related to the one worked out by Bertram. The scalar product formula allows to express the higher genus partition functions of the WZW conformal field theory by finite-dimensional integrals. It should provide the hermitian metric preserved by the Knizhnik-Zamolodchikov-Bernard connection describing the variations of the CS states under the change of the complex structure of the surface.Comment: 44 pages, IHES/P/94/10, Latex fil

    Embodied Evolution in Collective Robotics: A Review

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    This paper provides an overview of evolutionary robotics techniques applied to on-line distributed evolution for robot collectives -- namely, embodied evolution. It provides a definition of embodied evolution as well as a thorough description of the underlying concepts and mechanisms. The paper also presents a comprehensive summary of research published in the field since its inception (1999-2017), providing various perspectives to identify the major trends. In particular, we identify a shift from considering embodied evolution as a parallel search method within small robot collectives (fewer than 10 robots) to embodied evolution as an on-line distributed learning method for designing collective behaviours in swarm-like collectives. The paper concludes with a discussion of applications and open questions, providing a milestone for past and an inspiration for future research.Comment: 23 pages, 1 figure, 1 tabl
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