564 research outputs found
Logarithmic correction to scaling for multi-spin strings in the AdS_5 black hole background
We find new explicit solutions describing closed strings spinning with equal
angular momentum in two independent planes in the black hole spacetime.
These are folded strings in the radial direction and also winding
times around an angular direction. We especially consider these solutions in
the long string and high temperature limit, where it is shown that there is a
logarithmic correction to the scaling between energy and spin. This is similar
to the one-spin case. The strings are spinning, or actually orbiting around the
black hole of the black hole spacetime, similarly to solutions
previously found in black hole spacetimes.Comment: 11 pages, Final version, To appear in IJMP
Dynamics with Infinitely Many Time Derivatives and Rolling Tachyons
Both in string field theory and in p-adic string theory the equations of
motion involve infinite number of time derivatives. We argue that the initial
value problem is qualitatively different from that obtained in the limit of
many time derivatives in that the space of initial conditions becomes strongly
constrained. We calculate the energy-momentum tensor and study in detail time
dependent solutions representing tachyons rolling on the p-adic string theory
potentials. For even potentials we find surprising small oscillations at the
tachyon vacuum. These are not conventional physical states but rather
anharmonic oscillations with a nontrivial frequency--amplitude relation. When
the potentials are not even, small oscillatory solutions around the bottom must
grow in amplitude without a bound. Open string field theory resembles this
latter case, the tachyon rolls to the bottom and ever growing oscillations
ensue. We discuss the significance of these results for the issues of emerging
closed strings and tachyon matter.Comment: 46 pages, 14 figures, LaTeX. Replaced version: Minor typos corrected,
some figures edited for clarit
Yang-Mills theory from non-critical string
The correspondence of the non-critical string theory and the Yang-Mills
theory is examined according to the recent Polyakov's proposal, and two
possible solutions of the bulk equations are addressed near the fixed points of
the pure Yang-Mills theory: (i) One solution asymptotically approaches to the
AdS space at the ultraviolet limit where the conformally invariant field theory
is realized. (ii) The second one approaches to the flat space in both the
infrared and the ultraviolet limits. The area law of the Wilson-loop and the
asymptotic freedom with logarithmic behaviour are seen in the respective limit.Comment: 17 pages, no figure, Late
Beta-functions in Yang-Mills Theory from Non-critical String
The renormalization group equations of the Yang-Mills theory are examined in
the non-critical string theory according to the framework of the holography.
Under a simple ansatz for the tachyon, we could find several interesting
solutions which are classified by the value of the tachyon potential at the
vacuum. We show two typical, asymptotic-free solutions which are different in
their infrared behaviors. For both types of solutions, we could obtain
quark-confinement potential from the Wilson-loop. The stability of the tachyon
and the ZigZag symmetry are also discussed for these solutions.Comment: 16 pages, 5 figure
Quasilocality of joining/splitting strings from coherent states
Using the coherent state formalism we calculate matrix elements of the
one-loop non-planar dilatation operator of SYM between operators
dual to folded Frolov-Tseytlin strings and observe a curious scaling behavior.
We comment on the {\it qualitative} similarity of our matrix elements to the
interaction vertex of a string field theory. In addition, we present a solvable
toy model for string splitting and joining. The scaling behaviour of the matrix
elements suggests that the contribution to the genus one energy shift coming
from semi-classical string splitting and joining is small.Comment: 17 pages, 7 figures in 11 file
Aspects of Tachyonic Inflation with Exponential Potential
We consider issues related to tachyonic inflation with exponential potential.
We find exact solution of evolution equations in the slow roll limit in FRW
cosmology. We also carry out similar analysis in case of Brane assisted
tachyonic inflation. We investigate the phase space behavior of the system and
show that the dust like solution is a late time attractor. The difficulties
associated with reheating in the tachyonic model are also indicated.Comment: New References added. To appear in Phys. Rev.
New Global Defect Structures
We investigate the presence of defects in systems described by real scalar
field in (D,1) spacetime dimensions. We show that when the potential assumes
specific form, there are models which support stable global defects for D
arbitrary. We also show how to find first-order differential equations that
solve the equations of motion, and how to solve models in D dimensions via
soluble problems in D=1. We illustrate the procedure examining specific models
and finding explicit solutions.Comment: RevTex4, 4 pages, 3 eps figures; to be published in Phys. Rev. Let
Effective theory for wall-antiwall system
We propose a useful method for deriving the effective theory for a system
where BPS and anti-BPS domain walls coexist. Our method respects an
approximately preserved SUSY near each wall. Due to the finite width of the
walls, SUSY breaking terms arise at tree-level, which are exponentially
suppressed. A practical approximation using the BPS wall solutions is also
discussed. We show that a tachyonic mode appears in the matter sector if the
corresponding mode function has a broader profile than the wall width.Comment: LaTeX file, 30 page, 5 eps figures, references adde
On one-loop correction to energy of spinning strings in S^5
We revisit the computation (hep-th/0306130) of 1-loop AdS_5 x S^5 superstring
sigma model correction to energy of a closed circular string rotating in S^5.
The string is spinning around its center of mass with two equal angular momenta
J_2=J_3 and its center of mass angular momentum is J_1. We revise the argument
in hep-th/0306130 that the 1-loop correction is suppressed by 1/J factor (J=
J_1 + 2 J_2 is the total SO(6) spin) relative to the classical term in the
energy and use numerical methods to compute the leading 1-loop coefficient. The
corresponding gauge theory result is known (hep-th/0405055) only in the J_1=0
limit when the string solution becomes unstable and thus the 1-loop shift of
the energy formally contains an imaginary part. While the comparison with gauge
theory may not be well-defined in this case, our numerical string theory value
of the 1-loop coefficient seems to disagree with the gauge theory one. A
plausible explanation should be (as in hep-th/0405001) in the different order
of limits taken on the gauge theory and the string theory sides of the AdS/CFT
duality.Comment: 21 pages, 8 figure
Anomalous dimension and local charges
AdS space is the universal covering of a hyperboloid. We consider the action
of the deck transformations on a classical string worldsheet in . We argue that these transformations are generated by an infinite linear
combination of the local conserved charges. We conjecture that a similar
relation holds for the corresponding operators on the field theory side. This
would be a generalization of the recent field theory results showing that the
one loop anomalous dimension is proportional to the Casimir operator in the
representation of the Yangian algebra.Comment: 10 pages, LaTeX; v2: added explanations, reference
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