Testing the uniqueness of the open bosonic string field theory vacuum

The operators K_n are generators of reparameterization symmetries of Witten's cubic open string field theory. One pertinent question is whether they can be utilised to generate deformations of the tachyon vacuum and thereby violate its uniqueness. We use level truncation to show that these transformations on the vacuum are in fact pure gauge transformations to a very high accuracy, thus giving new evidence for the uniqueness of the perturbatively stable vacuum. Equivalently, this result implies the vanishing of some discrete cohomology classes of the BRST operator in the stable vacuum

NASA Contributions to Development of Special-Purpose Thermocouples. A Survey

The thermocouple has been used for measuring temperatures for more than a century, but new materials, probe designs, and techniques are continually being developed. Numerous contributions have been made by the National Aeronautics and Space Administration and its contractors in the aerospace program. These contributions have been collected by Midwest Research Institute and reported in this publication to enable American industrial engineers to study them and adapt them to their own problem areas. Potential applications are suggested to stimulate ideas on how these contributions can be used

Do shareholders of acquiring firms gain from acquisitions?

We examine a sample of 12,023 acquisitions by public firms from 1980 to 2001. Shareholders of these firms lost a total of $218 billion when acquisitions were announced. Though shareholders lose throughout our sample period, losses associated with acquisition announcements after 1997 are dramatic. Small firms gain from acquisitions, so that shareholders of small firms gained$8 billion when acquisitions were announced and shareholders of large firms lost $226 billion. We examine the cross-sectional variation in the announcement returns of acquisitions. Small firm shareholders earn systematically more when acquisitions are announced. This size effect is typically more important than how an acquisition is financed and than the organizational form of the assets acquired. The only acquisitions that have positive aggregate gains are acquisitions of subsidiaries.

Toward Open-Closed String Theoretical Description of Rolling Tachyon

We consider how the time-dependent decay process of an unstable D-brane should be described in the full (quantum) open-closed string theory. It is argued that the system, starting from the unstable D-brane configuration, will evolve in time into the time-independent open string tachyon vacuum configuration which we assume to be finite, with the total energy conserved. As a concrete realization of this idea, we construct a toy model describing the open and closed string tachyons which admits such a time-dependent solution. The structure of our model has some resemblance to that of open-closed string field theory.Comment: 1+10 pages, 6 figures. v2: a reference adde

On p-Adic Sector of Adelic String

We consider construction of Lagrangians which are candidates for p-adic sector of an adelic open scalar string. Such Lagrangians have their origin in Lagrangian for a single p-adic string and contain the Riemann zeta function with the d'Alembertian in its argument. In particular, we present a new Lagrangian obtained by an additive approach which takes into account all p-adic Lagrangians. The very attractive feature of this new Lagrangian is that it is an analytic function of the d'Alembertian. Investigation of the field theory with Riemann zeta function is interesting in itself as well.Comment: 10 pages. Presented at the 2nd Conf. on SFT and Related Topics, Moscow, April 2009. Submitted to Theor. Math. Phy

Zeta Nonlocal Scalar Fields

We consider some nonlocal and nonpolynomial scalar field models originated from p-adic string theory. Infinite number of spacetime derivatives is determined by the operator valued Riemann zeta function through d'Alembertian $\Box$ in its argument. Construction of the corresponding Lagrangians L starts with the exact Lagrangian $\mathcal{L}_p$ for effective field of p-adic tachyon string, which is generalized replacing p by arbitrary natural number n and then taken a sum of $\mathcal{L}_n$ over all n. The corresponding new objects we call zeta scalar strings. Some basic classical field properties of these fields are obtained and presented in this paper. In particular, some solutions of the equations of motion and their tachyon spectra are studied. Field theory with Riemann zeta function dynamics is interesting in its own right as well.Comment: 13 pages, submitted to Theoretical and Mathematical Physic

Closed String Amplitudes from Gauge Fixed String Field Theory

Closed string diagrams are derived from cubic open string field theory using a gauge fixed kinetic operator. The basic idea is to use a string propagator that does not generate a boundary to the world sheet. Using this propagator and the closed string vertex, the moduli space of closed string surfaces is covered, so closed string scattering amplitudes should be reproduced. This kinetic operator could be a gauge fixed form of the string field theory action around the closed string vacuum.Comment: 10 pages, revtex, 3 figures. Discussion on the covering of moduli expanded, version to appear in PR

Tachyon condensation on brane sphalerons

We consider a sphaleron solution in field theory that provides a toy model for unstable D-branes of string theory. We investigate the tachyon condensation on a Dp-brane. The localized modes, including a tachyon, arise in the spectrum of a sphaleron solution of a \phi^4 field theory on M^{p+1}\times S^1. We use these modes to find a multiscalar tachyon potential living on the sphaleron world-volume. A complete cancelation between brane tension and the minimum of the tachyon potential is found as the size of the circle becomes small.Comment: To appear in JHEP, 13 pages, 2 eps figures, minor changes and references adde