5,261 research outputs found

### Building string field theory around non-conformal backgrounds

The main limitations of string field theory arise because its present
formulation requires a background representing a classical solution, a
background defined by a strictly conformally invariant theory. Here we sketch a
construction for a gauge-invariant string field action around non-conformal
backgrounds. The construction makes no reference to any conformal theory. Its
two-dimensional field-theoretic aspect is based on a generalized BRST operator
satisfying a set of Weyl descent equations. Its geometric aspect uses a complex
of moduli spaces of two-dimensional Riemannian manifolds having ordinary
punctures, and organized by the number of special punctures which goes from
zero to infinity. In this complex there is a Batalin-Vilkovisky algebra that
includes naturally the operator which adds one special puncture. We obtain a
classical field equation that appears to relax the condition of conformal
invariance usually taken to define classical string backgrounds.Comment: 38 pages, 4 figures, phyzzx and BoxedEPS include

### Sub-Critical Closed String Field Theory in D Less Than 26

We construct the second quantized action for sub-critical closed string field
theory with zero cosmological constant in dimensions $2 \leq D < 26$,
generalizing the non-polynomial closed string field theory action proposed by
the author and the Kyoto and MIT groups for $D = 26$. The proof of gauge
invariance is considerably complicated by the presence of the Liouville field
$\phi$ and the non-polynomial nature of the action. However, we explicitly show
that the polyhedral vertex functions obey BRST invariance to all orders. By
point splitting methods, we calculate the anomaly contribution due to the
Liouville field, and show in detail that it cancels only if $D - 26 + 1 + 3 Q ^
2 = 0$, in both the bosonized and unbosonized polyhedral vertex functions. We
also show explicitly that the four point function generated by this action
reproduces the shifted Shapiro-Virasoro amplitude found from $c=1$ matrix
models and Liouville theory in two dimensions. LATEX file.Comment: 28 pages, CCNY-HEP-93-

### Causality in Covariant String Field Theory

Causality is studied in the covariant formulation of free string field theory
(SFT). We find that, though the string field in the covariant formulation is a
functional of the ghost coordinates as well as the space-time coordinate and
the latter contains the time-like oscillators with negative norm, the condition
for the commutator of two open string fields to vanish is simply given by
$\int_0^\pi d\sigma\left(\Delta X^\mu(\sigma)\right)^2 >0$, which is the same
condition as in the light-cone gauge SFT. For closed SFT, the corresponding
condition is given in a form which is manifestly invariant under the rigid
shifts of the $\sigma$ parameters of the two string fields.Comment: 11 pages + 1 eps figure, LaTe

### Effective Tachyonic Potential in Closed String Field Theory

We calculate the effective tachyonic potential in closed string field theory
up to the quartic term in the tree approximation. This involves an elementary
four-tachyon vertex and a sum over the infinite number of Feynman graphs with
an intermediate massive state. We show that both the elementary term and the
sum can be evaluated as integrals of some measure over different regions in the
moduli space of four-punctured spheres. We show that both elementary and
effective coupling give negative contributions to the quartic term in the
tachyon potential. Numerical calculations show that the fourth order term is
big enough to destroy a local minimum which exists in the third order
approximation.Comment: 41 pages, LaTeX + psfig macro package, 15 uuencoded tar-compressed
postscript figures include

### Information Spreading in Interacting String Field Theory

The commutator of string fields is considered in the context of light cone
string field theory. It is shown that the commutator is in general
non--vanishing outside the string light cone. This could have profound
implications for our understanding of the localization of information in
quantum gravity.Comment: 10 pages, 1 figure, harvmac and epsf, UCSBTH-94-07, SU-ITP-94-

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