166 research outputs found
Evidence for String Substructure
We argue that the behavior of string theory at high temperature and high
longitudinal boosts, combined with the emergence of p-branes as necessary
ingredients in various string dualities, point to a possible reformulation of
strings, as well as p-branes, as composites of bits. We review the string-bit
models, and suggest generalizations to incorporate p-branes.Comment: Latex file, 21 pages, 11 postscript figure
Galilean Supersymmetry in 2+1 Dimensions
We review work done in collaboration with C.B. Thorn on Super-Galilei
invariant field theory and its application to the reformulation of superstring
theory in terms of constituent superstring-bits.Comment: 10 pages, Latex. Talk given at the workshop on low dimensional field
theory, Telluride, C
A note on D0-branes and instantons in 5d supersymmetric gauge theories
We refine a previous proposal for obtaining the multi-instanton partition
function from the supersymmetric index of the 1d supersymmetric gauge theory on
the worldline of D0-branes. We provide examples where the refinements are
crucial for obtaining the correct result.Comment: 30 pages, 6 figures. Typos correcte
Branes and 2d N=(2,2) gauge theories with orthogonal and symplectic groups
We construct two-dimensional N=(2,2) supersymmetric gauge theories with
orthogonal and symplectic groups using branes and orientifold planes in Type
IIA string theory. A number of puzzles regarding the construction, including
the effect of exchanging NS5-branes on an orientifold 2-plane, are resolved by
lifting the configurations to M theory. The low energy properties and
conjectured dualities of these theories are reproduced in the M-brane
description. A similar construction of N=(4,4) theories with orthogonal and
symplectic groups leads to new duality conjectures for these theories.Comment: 22 pages, 27 figures. Type IIA linking number computation corrected
in section 4.5. Clarified and expanded the discussion of N=(4,4) dualities in
section 5. References adde
Anomalous radius shift in AdS(4)/CFT(3)
We study higher order corrections to the radius/M2-brane charge of AdS_4 x
S^7/Z_k. There are two sources of corrections: one from the orbifold
singularity of C^4/Z_k, and the other from the discrete torsion associated with
the homology 3-cycle H_3(S^7/Z_k,Z) = Z_k. We give a precise formula for the
charge shift. These corrections are relevant, for example, at two loops in the
AdS_4 x CP^3 sigma model, and therefore for the strong coupling test of the all
loop Bethe ansatz.Comment: 16 pages; v2: The Type IIA D-brane probe calculation has been
corrected, and now agrees with the M theory calculation. Appendix on
conventions for RR fields and D-brane actions added. Note added on a possible
correction due to a parity anomaly. References adde
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