5,686 research outputs found
Open String Field Theory around Universal Solutions
We study the physical spectrum of cubic open string field theory around
universal solutions, which are constructed using the matter Virasoro operators
and the ghost and anti-ghost fields. We find the cohomology of the new BRS
charge around the solutions, which appear with a ghost number that differs from
that of the original theory. Considering the gauge-unfixed string field theory,
we conclude that open string excitations perturbatively disappear after the
condensation of the string field to the solutions.Comment: 14 pages, LaTeX with ptptex.cls, typos correcte
Gauge Fixing and Scattering Amplitudes in String Field Theory Expanded around Universal Solutions
We study a gauge fixed action of open string field theory expanded around the
universal solution which has been found as an analytic classical solution with
one parameter a. For a>-1/2, we are able to reproduce open string scattering
amplitudes in the theory fixed in the Siegel gauge. At a=-1/2, all scattering
amplitudes vanish and there is no open string excitation in the gauge fixed
theory. These results support the conjecture that the universal solution can be
regarded as pure gauge or the tachyon vacuum solution.Comment: 23 pages, LaTeX with PTPTeX.cls, 1 eps figure. minor corrections,
published versio
Parity-violating electromagnetic interactions in QED_3 at finite temperature
We study the parity-breaking terms generated by the box diagram in 2+1
dimensional thermal QED. These lead, in the long wave limit, to a gauge
invariant extensive action which behaves as 1/T at high temperature. In
contrast, the effective action in the static limit involves leading
non-extensive terms proportional to 1/T^3 at high temperature, which violate
large gauge invariance. We derive a non-linear large gauge Ward identity, which
relates the leading static terms of different order in perturbation theory and
whose solution coincides with the all order effective action proposed earlier.Comment: 25 pages, 3 figure
Dispersion relations for the self-energy in non-commutative field theories
We study the IR/UV connection in non-commutative theory as well as
in non-commutative QED from the point of view of the dispersion relation for
the self-energy. We show that, although the imaginary part of the self-energy
is well behaved as the parameter of non-commutativity vanishes, the real part
becomes divergent as a consequence of the high energy behavior of the
dispersion integral. Some other interesting features that arise from this
analysis are also briefly discussed.Comment: 10 page
Thermal instability in a gravity-like scalar theory
We study the question of stability of the ground state of a scalar theory
which is a generalization of the phi^3 theory and has some similarity to
gravity with a cosmological constant. We show that the ground state of the
theory at zero temperature becomes unstable above a certain critical
temperature, which is evaluated in closed form at high temperature.Comment: Four pages, two figures. Revised version published in the Physical
Review
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