1,249 research outputs found
Natural curvature for manifest T-duality
We reformulate the manifestly T-dual description of the massless sector of
the closed bosonic string, directly from the geometry associated with the (left
and right) affine Lie algebra of the coset space Poincare/Lorentz. This
construction initially doubles not only the (spacetime) coordinates for
translations but also those for Lorentz transformations (and their dual). As a
result, the Lorentz connection couples directly to the string (as does the
vielbein), rather than being introduced ad hoc to the covariant derivative as
previously. This not only reproduces the old definition of T-dual torsion, but
automatically gives a general, covariant definition of T-dual curvature (but
still with some undetermined connections).Comment: Minor changes in notations (see e.g. eq.(7), eq.(8)). Some typos
corrected: e.g factor "i" in equations (11) and (12). New references adde
Gauge-covariant S-matrices for field theory and strings
S-matrices can be written Lorentz covariantly in terms of free field
strengths for vector states, allowing arbitrary gauge choices. In string theory
the vertex operators can be chosen so this gauge invariance is automatic. As
examples we give four-vector (super)string tree amplitudes in this form, and
find the field theory actions that give the first three orders in the slope.Comment: 11 pages, 3 figures, reference adde
T-duality off shell in 3D Type II superspace
We give the manifestly T-dual formulation of the massless sector of the
classical 3D Type II superstring in off-shell 3D N=2 superspace, including the
action. It has a simple relation to the known superspace of 4D N=1 supergravity
in 4D M-theory via 5D F-theory. The pre potential appears as part of the
vielbein, without derivatives.Comment: References added, factor of 2 in the algebra (8) fixe
O(D,D) gauge fields in the T-dual string Lagrangian
We present the string Lagrangian with manifest T-duality. Not only zero-modes
but also all string modes are doubled. The gravitational field is an O(D,D)
gauge field. We give a Lagrangian version of the section condition for the
gauge invariance which compensates the O(D,D) transformation from the
gravitational field and the GL(2D) coordinate transformation. We also show the
gauge invariance of the line element of the manifest T-duality space and the
O(D,D) condition on the background. Different sections describe dual spaces.Comment: 18 pages, Lualatex; v2: version appears in JHEP, added references,
detailed explanations are added, Lualatex file available at
http://insti.physics.sunysb.edu/~siegel/tex.shtm
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