294 research outputs found
D-branes and Closed String Field Theory
We construct solitonic states in the OSp invariant string field theory, which
are BRST invariant in the leading order of regularization parameter. One can
show that these solitonic states describe D-branes and ghost D-branes, by
calculating the scattering amplitudes.Comment: 8 pages, 2 figures, based on an invited talk presented at the
international workshop "Progress of String Theory and Quantum Field Theory"
(Osaka City University, December 7-10, 2007), to be published in the
proceeding
Observables and Correlation Functions in OSp Invariant String Field Theory
We define BRST invariant observables in the OSp invariant closed string field
theory for bosonic strings. We evaluate correlation functions of these
observables and show that the S-matrix elements derived from them coincide with
those of the light-cone gauge string field theory.Comment: 23 page
Light-Cone Gauge String Field Theory in Noncritical Dimensions
We study light-cone gauge string field theory in noncritical space-time
dimensions. Such a theory corresponds to a string theory in a Lorentz
noninvariant background. We identify the worldsheet theory for the longitudinal
coordinate variables and study its properties. It is a CFT with the
right value of Virasoro central charge, using which we propose a BRST invariant
formulation of the worldsheet theory.Comment: 27 pages, 2 figure
Light-cone Gauge NSR Strings in Noncritical Dimensions
Light-cone gauge NSR string theory in noncritical dimensions should
correspond to a string theory with a nonstandard longitudinal part.
Supersymmetrizing the bosonic case [arXiv:0909.4675], we formulate a
superconformal worldsheet theory for the longitudinal variables X^{\pm},
\psi^{\pm}. We show that with the transverse variables and the ghosts combined,
it is possible to construct a nilpotent BRST charge.Comment: 22 pages, 1 figur
D-brane States and Annulus Amplitudes in OSp Invariant Closed String Field Theory
In the OSp invariant closed string field theory, we construct the states
corresponding to parallel D-branes that are located at different points in the
space-time. Using these states, we evaluate annulus amplitudes. We show that
the results coincide with those of first quantized string theory.Comment: 14 pages, 3 figure
An Algorithm for On-Line Digital Image Processing for Assisting Automatic Focusing and Astigmatism Correction in Electron Microscopy
An algorithm for processing a diffractogram of an electron image input by an on-line system has been improved, with the aid of projection theory, so as to achieve real time operation. This algorithm can, therefore, automatically focus in scanning electron microscope, and correct for the astigmatic aberration of both transmission and scanning electron microscopes by analyzing the spectrum computed from the diffractogram. Experimental results show that this algorithm is effective for detecting the amount of defocus and astigmatism in both transmission and scanning electron microscopes
D-brane States and Disk Amplitudes in OSp Invariant Closed String Field Theory
We construct solitonic states in the OSp invariant string field theory, which
are BRST invariant in the leading order of regularization parameter .
We calculate the disk amplitudes using these solitonic states and show that
they describe D-branes and ghost D-branes.Comment: 37 pages, 8 figure
Light-cone Gauge Superstring Field Theory and Dimensional Regularization II
We propose a dimensional regularization scheme to deal with the divergences
caused by colliding supercurrents inserted at the interaction points, in the
light-cone gauge NSR superstring field theory. We formulate the theory in
dimensions and define the amplitudes as analytic functions of . With an
appropriately chosen three-string interaction term and large negative , the
tree level amplitudes for the (NS,NS) closed strings can be recast into a BRST
invariant form, using the superconformal field theory proposed in
Ref.[arXiv:0911.3704]. We show that in the limit they coincide with
the results of the first quantized theory. Therefore we obtain the desired
results without adding any contact interaction terms to the action.Comment: 23 pages; v2: minor modifications; v3: revised argument in section 3,
added appendix C, results unchanged; v4: added clarifications, two figures
and a footnote; v5: minor modification
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