5,144 research outputs found
Exceptional sheaves on the Hirzebruch surface Fâ‚‚
We investigate exceptional sheaves on the Hirzebruch surface ,
as the first attempt toward the classification of exceptional objects on weak
del Pezzo surfaces.Comment: 25 page
Conformal Symmetry and A New Gauge in the Matrix Model
We generalize the background gauge in the Matrix model to propose a new gauge
which is useful for discussing the conformal symmetry. In this gauge, the
special conformal transformation (SCT) as the isometry of the near-horizon
geometry of the D-particle solution is directly reproduced with the correct
coefficient as the quantum correction to the SCT in the Matrix model. We also
present a general argument for the relation between the gauge choice and the
field redefinition in the Matrix model.Comment: 17 pages, LaTeX, no figures; v2: Introduction modified, references
added and typos corrected; v3: Introduction changed; v4: Eq.(12) corrected;
v5: final version to appear in Phys. Rev.
Renormalization of four-fermion operators for higher twist calculations
The evaluation of the higher twist contributions to Deep Inelastic Scattering
amplitudes involves a non trivial choice of operator bases for the higher
orders of the OPE expansion of the two hadronic currents. In this talk we
discuss the perturbative renormalization of the four-fermion operators that
appear in the above bases.Comment: LATTICE98(matrixelement), 3 page
Tachyon Vacuum Solution in Open String Field Theory with Constant B Field
We show that Schnabl's tachyon vacuum solution is an exact solution of the
equation of motion of Witten's open bosonic string field theory in the
background of constant antisymmetric two-form field. The action computed at the
vacuum solution is given by the Dirac-Born-Infeld factor multiplied to that
without the antisymmetric tensor field.Comment: 8 page
Noncommuting Gauge Fields as a Lagrange Fluid
The Lagrange description of an ideal fluid gives rise in a natural way to a
gauge potential and a Poisson structure that are classical precursors of
analogous noncommuting entities. With this observation we are led to construct
gauge-covariant coordinate transformations on a noncommuting space. Also we
recognize the Seiberg-Witten map from noncommuting to commuting variables as
the quantum correspondent of the Lagrange to Euler map in fluid mechanics.Comment: 19 pages; final version to appear in Annals of Physic
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