164 research outputs found
DLCQ and Plane Wave Matrix Big Bang Models
We study the generalisations of the Craps-Sethi-Verlinde matrix big bang
model to curved, in particular plane wave, space-times, beginning with a
careful discussion of the DLCQ procedure. Singular homogeneous plane waves are
ideal toy-models of realistic space-time singularities since they have been
shown to arise universally as their Penrose limits, and we emphasise the role
played by the symmetries of these plane waves in implementing the flat space
Seiberg-Sen DLCQ prescription for these curved backgrounds. We then analyse
various aspects of the resulting matrix string Yang-Mills theories, such as the
relation between strong coupling space-time singularities and world-sheet
tachyonic mass terms. In order to have concrete examples at hand, in an
appendix we determine and analyse the IIA singular homogeneous plane wave -
null dilaton backgrounds.Comment: 29 pages, v2: reference added + minor cosmetic correction
On Consistent Boundary Conditions for c=1 String Theory
We introduce a new parametrisation for the Fermi sea of the matrix
model. This leads to a simple derivation of the scattering matrix, and a
calculation of boundary corrections in the corresponding --dimensional
string theory. The new parametrisation involves relativistic chiral fields,
rather than the non-relativistic fields of the usual formulations. The
calculation of the boundary corrections, following recent work of Polchinski,
allows us to place restrictions on the boundary conditions in the matrix model.
We provide a consistent set of boundary conditions, but believe that they need
to be supplemented by some more subtle relationship between the space-time and
matrix model. Inspired by these boundary conditions, some thoughts on the black
hole in string theory are presented.Comment: 13 pages, 2 postscript figures include
The use and utility of surrogates in biodiversity monitoring programmes
**Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Philip Barton” is provided in this record*
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