67 research outputs found
Tachyon Backgrounds in 2D String Theory
We consider the construction of tachyonic backgrounds in two-dimensional
string theory, focusing on the Sine-Liouville background. This can be studied
in two different ways, one within the context of collective field theory and
the other via the formalism of Toda integrable systems. The two approaches are
seemingly different. The latter involves a deformation of the original inverted
oscillator potential while the former does not. We perform a comparison by
explicitly constructing the Fermi surface in each case, and demonstrate that
the two apparently different approaches are in fact equivalent.Comment: 25 pages, no figure
Collective Field Description of Matrix Cosmologies
We study the Das-Jevicki collective field description of arbitrary classical
solutions in the c=1 matrix model, which are believed to describe nontrivial
spacetime backgrounds in 2d string theory. Our analysis naturally includes the
case of a Fermi droplet cosmology: a finite size droplet of Fermi fluid, made
up of a finite number of eigenvalues. We analyze properties of the coordinates
in which the metric in the collective field theory is trivial, and comment on
the form of the interaction terms in these coordinates.Comment: 16 pages, 1 figure. v2: Typos corrected, JHEP styl
Condensing Momentum Modes in 2-d 0A String Theory with Flux
We use a combination of conformal perturbation theory techniques and matrix
model results to study the effects of perturbing by momentum modes two
dimensional type 0A strings with non-vanishing Ramond-Ramond (RR) flux. In the
limit of large RR flux (equivalently, mu=0) we find an explicit analytic form
of the genus zero partition function in terms of the RR flux and the
momentum modes coupling constant alpha. The analyticity of the partition
function enables us to go beyond the perturbative regime and, for alpha>> q,
obtain the partition function in a background corresponding to the momentum
modes condensation. For momenta such that 0<p<2 we find no obstruction to
condensing the momentum modes in the phase diagram of the partition function.Comment: 22 page
Brane Intersections in the Presence of a Worldvolume Electric Field
The study of brane intersections has provided important insights into a
possible non-commutative structure of spacetime geometry. In this paper we
focus on the D1D3 system. We compare the D1 and D3 descriptions of the
interesection and search for non-static solutions of the D3D1 funnel
equations in the presence of a worldvolume electric field. We find that the D1
and D3 descriptions do not agree. We find time dependent solutions that are a
natural generalization of those found without the electric field.Comment: 10 page
Areas and entropies in BFSS/gravity duality
The BFSS matrix model provides an example of gauge-theory / gravity duality
where the gauge theory is a model of ordinary quantum mechanics with no spatial
subsystems. If there exists a general connection between areas and entropies in
this model similar to the Ryu-Takayanagi formula, the entropies must be more
general than the usual subsystem entanglement entropies. In this note, we first
investigate the extremal surfaces in the geometries dual to the BFSS model at
zero and finite temperature. We describe a method to associate regulated areas
to these surfaces and calculate the areas explicitly for a family of surfaces
preserving symmetry, both at zero and finite temperature. We then
discuss possible entropic quantities in the matrix model that could be dual to
these regulated areas.Comment: 29 pages, 3 figures. v2 Examples in section 6 moved to appendix.
Minor comments adde
Quadratic alpha' corrections to T-duality
The quadratic alpha' corrections to the two-dimensional black hole and to its
T-dual are calculated. These backgrounds are used to write the covariant form
of the quadratic alpha' corrections to the T-duality for general time-dependent
backgrounds of dilaton and diagonal metric in the bosonic string theory.Comment: 15 pages, JHEP; typos corrected, references adde
Energy Quantisation in Bulk Bouncing Tachyon
We argue that the closed string energy in the bulk bouncing tachyon
background is to be quantised in a simple manner as if strings were trapped in
a finite time interval. We discuss it from three different viewpoints; (1) the
timelike continuation of the sinh-Gordon model, (2) the dual matrix model
description of the (1+1)-dimensional string theory with the bulk bouncing
tachyon condensate, (3) the c_L=1 limit of the timelike Liouville theory with
the dual Liouville potential turned on. There appears to be a parallel between
the bulk bouncing tachyon and the full S-brane of D-brane decay. We find the
critical value \lambda_c of the bulk bouncing tachyon coupling which is
analogous to \lambda_o=1/2 of the full S-brane coupling, at which the system is
thought to be at the bottom of the tachyon potential.Comment: 25 pages, minor changes, one reference adde
The stringy nature of the 2d type-0A black hole
We investigate the thermodynamics of the RR charged two-dimensional type-0A
black hole background at finite temperature, and compare with known 0A matrix
model results. It has been claimed that there is a disagreement for the free
energy between the spacetime and the dual matrix model. Here we find that this
discrepancy is sensitive to how the cutoff is implemented on the spacetime
side. In particular, the disagreement is resolved once we put the cutoff at a
fixed distance away from the horizon, as opposed to a fixed position in space.
Furthermore, the mass and the entropy of the black hole itself add up to an
analytic contribution to the free energy, which is precisely reproduced by the
0A matrix model. We also use results from the 0A matrix model to predict the
next to leading order contribution to the entropy of the black hole. Finally,
we note that the black hole is characterized by a Hagedorn growth in its
density of states below the Hagedorn temperature. This, together with other
results, suggests there is a phase transition at this temperature.Comment: 1+21 pages; v2: Substantial changes in the body of the paper, main
results the same. Clarified discussion on the thermodynamics, added section
on a phase transition, references added. v3: Typos corrected. v4: Final
version, to appear in JHE
c < 1 String from Two Dimensional Black Holes
We study a topological string description of the c < 1 non-critical string
whose matter part is defined by the time-like linear dilaton CFT. We show that
the topologically twisted N=2 SL(2,R)/U(1) model (or supersymmetric 2D black
hole) is equivalent to the c < 1 non-critical string compactified at a specific
radius by comparing their physical spectra and correlation functions. We
examine another equivalent description in the topological Landau-Ginzburg model
and check that it reproduces the same scattering amplitudes. We also discuss
its matrix model dual description.Comment: 36 pages, harvmac; acknowledgements, comments and references adde
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