3,221 research outputs found
The Stringy Quantum Hall Fluid
Using branes in massive Type IIA string theory, and a novel decoupling limit,
we provide an explicit correspondence between non-commutative Chern-Simons
theory and the fractional quantum Hall fluid. The role of the electrons is
played by D-particles, the background magnetic field corresponds to a RR 2-form
flux, and the two-dimensional fluid is described by non-commutative D2-branes.
The filling fraction is given by the ratio of the number of D2-branes and the
number of D8-branes, and therefore by the ratio rank/level of the Chern-Simons
gauge theory. Quasiparticles and quasiholes are realized as endpoints of
fundamental strings on the D2-branes, and are found to possess fractional
D-particle charges and fractional statistics.Comment: 24 pages, 2 figures; references adde
Tachyon Vacuum Solution in Open String Field Theory with Constant B Field
We show that Schnabl's tachyon vacuum solution is an exact solution of the
equation of motion of Witten's open bosonic string field theory in the
background of constant antisymmetric two-form field. The action computed at the
vacuum solution is given by the Dirac-Born-Infeld factor multiplied to that
without the antisymmetric tensor field.Comment: 8 page
Tachyon Condensation with B-field
We discuss classical solutions of a graviton-dilaton-B_{\mu\nu}-tachyon
system. Both constant tachyon solutions, including AdS_3 solutions, and
space-dependent tachyon solutions are investigated, and their possible
implications to closed string tachyon condensation are argued. The stability
issue of the AdS_3 solutions is also discussed.Comment: 10 pages, references adde
Fluctuations around the Tachyon Vacuum in Open String Field Theory
We consider quadratic fluctuations around the tachyon vacuum numerically in
open string field theory. We work on a space spanned
by basis string states used in the Schnabl's vacuum solution. We show that the
truncated form of the Schnabl's vacuum solution on is
well-behaved in numerical work. The orthogonal basis for the new BRST operator
on and the quadratic forms of potentials
for independent fields around the vacuum are obtained. Our numerical results
support that the Schnabl's vacuum solution represents the minimum energy
solution for arbitrary fluctuations also in open string field theory.Comment: 16 pages, 2 figures, some comments and one table added, version to
appear in JHE
Compact Lattice QED and the Coulomb Potential
The potential energy of a static charge distribution on a lattice is
rigorously computed in the standard compact quantum electrodynamic model. The
method used follows closely that of Weyl for ordinary quantum electrodynamics
in continuous space-time. The potential energy of the static charge
distribution is independent of temperature and can be calculated from the
lattice version of Poisson's equation. It is the usual Coulomb potential.Comment: 6 pages, includes one figure in Topdrawer, NUB 3054/9
The energy of the analytic lump solution in SFT
In a previous paper a method was proposed to find exact analytic solutions of
open string field theory describing lower dimensional lumps, by incorporating
in string field theory an exact renormalization group flow generated by a
relevant operator in a worldsheet CFT. In this paper we compute the energy of
one such solution, which is expected to represent a D24 brane. We show, both
numerically and analytically, that its value corresponds to the theoretically
expected one.Comment: 45 pages, former section 2 suppressed, Appendix D added, comments and
references added, typos corrected. Erratum adde
The nonperturbative closed string tachyon vacuum to high level
We compute the action of closed bosonic string field theory at quartic order
with fields up to level ten. After level four, the value of the potential at
the minimum starts oscillating around a nonzero negative value, in contrast
with the proposition made in [5]. We try a different truncation scheme in which
the value of the potential converges faster with the level. By extrapolating
these values, we are able to give a rather precise value for the depth of the
potential.Comment: 24 pages. v2: typos corrected, clarified extrapolation in scheme B,
and added extrapolated tachyon and dilaton vev's at the end of Section
On fluctuations of closed string tachyon solitons
We discuss fluctuations on solitons in the dilaton/graviton/tachyon system
using the low energy effective field theory approach. It is shown that closed
string solitons are free of tachyons in this approximation, regardless of the
exact shape of the tachyon potential.Comment: 13 pages, 1 figure, uses JHEP3.cl
Rolling Closed String Tachyons and the Big Crunch
We study the low-energy effective field equations that couple gravity, the
dilaton, and the bulk closed string tachyon of bosonic closed string theory. We
establish that whenever the tachyon induces the rolling process, the string
metric remains fixed while the dilaton rolls to strong coupling. For negative
definite potentials we show that this results in an Einstein metric that
crunches the universe in finite time. This behavior is shown to be rather
generic even if the potentials are not negative definite. The solutions are
reminiscent of those in the collapse stage of a cyclic universe cosmology where
scalar field potentials with negative energies play a central role.Comment: 13 pages, 2 figures, LaTeX. Replaced version: one reference adde
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