184,118 research outputs found
Long String Scattering in c = 1 String Theory
We study the scattering of long strings in c = 1 string theory, both in the
worldsheet description and in the non-singlet sector of the dual matrix quantum
mechanics. From the worldsheet perspective, the scattering amplitudes of long
strings are obtained from a decoupling limit of open strings amplitudes on FZZT
branes, which we compute by integrating Virasoro conformal blocks along with
structure constants of boundary Liouville theory. In particular, we study the
tree level amplitudes of (1) a long string decaying by emitting a closed
string, and (2) the scattering of a pair of long strings. We show that they are
indeed well defined as limits of open string amplitudes, and that our results
are in striking numerical agreement with computations in the adjoint and
bi-adjoint sectors of the dual matrix model (based on proposals of Maldacena
and solutions due to Fidkowski), thereby providing strong evidence of the
duality.Comment: 42 pages, 18 figure
Anomalies and large N limits in matrix string theory
We study the loop expansion for the low energy effective action for matrix
string theory. For long string configurations we find the result depends on the
ordering of limits. Taking before we find free strings.
Reversing the order of limits however we find anomalous contributions coming
from the large limit that invalidate the loop expansion. We then embed the
classical instanton solution into a long string configuration. We find the
instanton has a loop expansion weighted by fractional powers of . Finally we
identify the scaling regime for which interacting long string configurations
have a well defined large limit. The limit corresponds to large "classical"
strings and can be identified with the "dual of the 't Hooft limit,
.Comment: 13 pages, 1 figure, harvmac.tex, notational errors corrected,
references added. Trivial error in section 5 corrected with the result that
the domain of validity of the loop expn. is slightly modifie
Newtonian Gravitons and D-brane Collective Coordinates in Wound String Theory
Recently it was shown that NCOS theories are part of a ten-dimensional theory
known as Non-relativistic Wound string theory. We clarify the sense in which
gravity is present in this theory. We show that Wound string theory contains
exceptional unwound strings, including a graviton, which mediate the previously
discovered instantaneous long-range interactions, but are negligible as
asymptotic states. Unwound strings also provide the expected collective
coordinates for the transverse D-branes in the theory. These and other results
are shown to follow both from a direct analysis of the effect of the NCOS limit
on the parent string theory, and from the worldsheet formalism developed by
Gomis and Ooguri, about which we make some additional remarks. We also devote
some attention to supergravity duals, and in particular show that the open and
closed strings of the theory are respectively described by short and long
strings on the supergravity side.Comment: LaTeX 2e, 31+1 pages; v2: minor changes, reference added; v3: 2
paragraphs on transverse D-branes added (end of Secs. 3.1 and 5), final
version to appear in JHE
On Fine Structure of Strings: The Universal Correction to the Veneziano Amplitude
We consider theories of weakly interacting higher spin particles in flat
spacetime. We focus on the four-point scattering amplitude at high energies and
imaginary scattering angles. The leading asymptotic of the amplitude in this
regime is universal and equal to the corresponding limit of the Veneziano
amplitude. In this paper, we find that the first sub-leading correction to this
asymptotic is universal as well. We compute the correction using a model of
relativistic strings with massive endpoints. We argue that it is unique using
holography, effective theory of long strings and bootstrap techniques.Comment: 54 pages, 5 figure
Confinement in the Abelian-Higgs-type theories: string picture and field correlators
Field correlators and the string representation are used as two complementary
approaches for the description of confinement in the SU(N)-inspired dual
Abelian-Higgs-type model. In the London limit of the simplest, SU(2)-inspired,
model, bilocal electric field-strength correlators have been derived with
accounting for the contributions to these averages produced by closed dual
strings. The Debye screening in the plasma of such strings yields a novel
long-range interaction between points lying on the contour of the Wilson loop.
This interaction generates a Luescher-type term, even when one restrics oneself
to the minimal surface, as it is usually done in the bilocal approximation to
the stochastic vacuum model. Beyond the London limit, it has been shown that a
modified interaction appears, which becomes reduced to the standard Yukawa one
in the London limit. Finally, a string representation of the SU(N)-inspired
model with the theta-term, in the London limit, can be constructed.Comment: 17 pages, no figures, REVTeX 4; Invited contribution to the
collection of articles devoted to the 70th birthday of Yu.A. Simono
Tensionless Strings from Worldsheet Symmetries
We revisit the construction of the tensionless limit of closed bosonic string
theory in the covariant formulation in the light of Galilean conformal symmetry
that rises as the residual gauge symmetry on the tensionless worldsheet. We
relate the analysis of the fundamentally tensionless theory to the tensionless
limit that is viewed as a contraction of worldsheet coordinates. Analysis of
the quantum regime uncovers interesting physics. The degrees of freedom that
appear in the tensionless string are fundamentally different from the usual
string states. Through a Bogoliubov transformation on the worldsheet, we link
the tensionless vacuum to the usual tensile vacuum. As an application, we show
that our analysis can be used to understand physics of strings at very high
temperatures and propose that these new degrees of freedom are naturally
connected with the long-string picture of the Hagedorn phase of free string
theory. We also show that tensionless closed strings behave like open strings.Comment: 40 pages; v2: references added, minor text edit
Integrable Hamiltonian for Classical Strings on AdS_5 x S^5
We find the Hamiltonian for physical excitations of the classical bosonic
string propagating in the AdS_5 x S^5 space-time. The Hamiltonian is obtained
in a so-called uniform gauge which is related to the static gauge by a 2d
duality transformation. The Hamiltonian is of the Nambu type and depends on two
parameters: a single S^5 angular momentum J and the string tension \lambda. In
the general case both parameters can be finite. The space of string states
consists of short and long strings. In the sector of short strings the large J
expansion with \lambda'=\lambda/J^2 fixed recovers the plane-wave Hamiltonian
and higher-order corrections recently studied in the literature. In the strong
coupling limit \lambda\to \infty, J fixed, the energy of short strings scales
as \sqrt[4]{\lambda} while the energy of long strings scales as \sqrt{\lambda}.
We further show that the gauge-fixed Hamiltonian is integrable by constructing
the corresponding Lax representation. We discuss some general properties of the
monodromy matrix, and verify that the asymptotic behavior of the quasi-momentum
perfectly agrees with the one obtained earlier for some specific cases.Comment: 30 pages, LaTex; v2: a few comments added, misprints corrected,
references adde
Semiclassical relativistic strings in S^5 and long coherent operators in N=4 SYM theory
We consider the low energy effective action corresponding to the 1-loop,
planar, dilatation operator in the scalar sector of N=4 SU(N) SYM theory. For a
general class of non-holomorphic ``long'' operators, of bare dimension L>>1, it
is a sigma model action with 8-dimensional target space and agrees with a limit
of the phase-space string sigma model action describing generic fast-moving
strings in the S^5 part of AdS_5 x S^5. The limit of the string action is taken
in a way that allows for a systematic expansion to higher orders in the
effective coupling . This extends previous work on rigid rotating
strings in S^5 (dual to operators in the SU(3) sector of the dilatation
operator) to the case when string oscillations or pulsations in S^5 are
allowed. We establish a map between the profile of the leading order string
solution and the structure of the corresponding coherent, ``locally BPS'', SYM
scalar operator. As an application, we explicitly determine the form of the
non-holomorphic operators dual to the pulsating strings. Using action--angle
variables, we also directly compute the energy of pulsating solutions,
simplifying previous treatments.Comment: LaTeX, 50 pages, 1 figure. v2: References added, minor corrections.
54 pages. v3: Few changes. One paragraph added at the end of section 3. 55
page
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