25,868 research outputs found
From Boundaries To Conditions Over Superspace
N=1 and 2 superconformal boundary conditions are shown to be the consequence
of a boundary on the worldsheet superspace with positive codimension in the
anticommuting subspace. In addition to the well-known boundary conditions, I
also find two new infinite series of N=2 boundary states. Their free field
realizations are given. A self-contained development of 2d superspace leads to
new perspectives on this subject.Comment: 25 page
A systematic study of the initial state in heavy ion collisions based on the quark participant assumption
We investigate the initial state geometric quantities of heavy ion collisions
based on the quark participant assumption in the Glauber multiple scattering
approach. A systematic comparison to the nucleon participant assumption has
been presented and confronted with the charged multiplicity measurements in
various collision systems. It is found that the quark participant based
assumption can be important to understand the data in multiplicity production
and the initial spatial eccentricity in small systems.Comment: 7 pages, 10 figure
TASI Lectures on Perturbative String Theories
These lecture notes are based on a course on string theories given by Hirosi
Ooguri in the first week of TASI 96 Summer School at Boulder, Colorado. It is
an introductory course designed to provide students with minimum knowledge
before they attend more advanced courses on non-perturbative aspects of string
theories in the School. The course consists of five lectures: 1. Bosonic
String, 2. Toroidal Compactifications, 3. Superstrings, 4. Heterotic Strings,
and 5. Orbifold Compactifications.Comment: 80 pages, Latex, final version to appear in the Proceedings of TASI9
A Note On Space Noncommutativity
We consider a two-point spatial lattice approximation to an open string
moving in a flat background with B field. It gives a constrained dipole system
under the influence of a vector potential. Solving and quantizing this system
recover all the essential features of a noncommutative space. In particular,
open string interactions induce a canonical product structure on the Hilbert
space of the dipole system. It coincides with the usual star product, even
though the position operators can be thought of as mutually commuting.
Modification of gauge transformations in this noncommutative space also
naturally emerges.Comment: 10 pages, no figure, LaTeX 2.09. Some typographical correction
D-Branes on Calabi-Yau Spaces and Their Mirrors
We study the boundary states of D-branes wrapped around supersymmetric cycles
in a general Calabi-Yau manifold. In particular, we show how the geometric data
on the cycles are encoded in the boundary states. As an application, we analyze
how the mirror symmetry transforms D-branes, and we verify that it is
consistent with the conjectured periodicity and the monodromy of the
Ramond-Ramond field configuration on a Calabi-Yau manifold. This also enables
us to study open string worldsheet instanton corrections and relate them to
closed string instanton counting. The cases when the mirror symmetry is
realized as T-duality are also discussed.Comment: 28 pages, LaTeX. The description of the large complex structure limit
is corrected. The mirror transformation between D-branes is further clarifie
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