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22
Tachyon matter in boundary string field theory
 JHEP
, 2002
"... Dedicated to the memory of SungKil Yang We analyse the classical decay process of unstable Dbranes in superstring theory using the boundary string field theory (BSFT) action. We show that the solutions of the equations of motion for the tachyon field asymptotically approach to T = x 0 and the pres ..."
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Cited by 52 (5 self)
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Dedicated to the memory of SungKil Yang We analyse the classical decay process of unstable Dbranes in superstring theory using the boundary string field theory (BSFT) action. We show that the solutions of the equations of motion for the tachyon field asymptotically approach to T = x 0 and the pressure rapidly falls off at late time producing the tachyon matter irrespective of the initial condition. We also consider the cosmological evolution driven by the rolling tachyon using the BSFT action as an effective action. 1
New solution of the open bosonic string field theory,” arXiv:hepth/0205294
"... Preprint typeset in JHEP style. HYPER VERSION ..."
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An Improved Brane AntiBrane Action from Boundary Superstring Field Theory
 and MultiVortex Solutions”, JHEP 0301 (2003) 012, hepth/0211180
"... Abstract: We present an improved effective action for the DbraneantiDbrane system obtained from boundary superstring field theory. Although the action looks highly nontrivial, it has simple explicit multivortex (i.e. codimension2 multiBPS Dbrane) multiantivortex solutions. The solutions hav ..."
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Cited by 31 (7 self)
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Abstract: We present an improved effective action for the DbraneantiDbrane system obtained from boundary superstring field theory. Although the action looks highly nontrivial, it has simple explicit multivortex (i.e. codimension2 multiBPS Dbrane) multiantivortex solutions. The solutions have a curious degeneracy corresponding to different “magnetic ” fluxes at the core of each vortex. We also generalize the brane antibrane effective action that is suitable for the study of the inflationary scenario and the production of defects in the early universe. We show that when a brane and antibrane are distantly separated, although the system is classically stable it can decay via quantum tunneling through the barrier. Keywords: DBranes; Tachyon Condenstaion; Superstrings and Heterotic Strings;
Worldsheet Description of Tachyon Condensation in Open String Theory
, 2003
"... In this thesis we review the fundamental framework of boundary string field theory (BSFT) and apply it to the tachyon condensation on nonBPS systems in the superstring theory. The boundary string field theory can be regarded as a natural extension of the nonlinear sigma model. By using this theory ..."
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Cited by 5 (0 self)
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In this thesis we review the fundamental framework of boundary string field theory (BSFT) and apply it to the tachyon condensation on nonBPS systems in the superstring theory. The boundary string field theory can be regarded as a natural extension of the nonlinear sigma model. By using this theory we can describe the tachyon condensation exactly and also obtain the effective actions on nonBPS systems consisting of the DiracBornInfeld type action and the WessZumino type action. Especially the WessZumino action is written by superconnection and coincides with the mathematical argument by Ktheory. Moreover we also discuss the tachyon condensation keeping the conformal invariance (onshell). The exact argument by using the boundary state formalism gives a good support to the conjecture of the tachyon condensation and it is also
Spacelike and Time Dependent Branes from DBI
 J. High Energy Phys
"... Spacelike branes are new timedependent systems to explore and it has been observed that related supergravity solutions can be obtained by analytically continuing known Dbrane solutions. Here we show that analytic continuation of known solutions of the DiracBornInfeld equations also lead to inter ..."
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Cited by 3 (0 self)
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Spacelike branes are new timedependent systems to explore and it has been observed that related supergravity solutions can be obtained by analytically continuing known Dbrane solutions. Here we show that analytic continuation of known solutions of the DiracBornInfeld equations also lead to interesting analogs of time dependent gravity solutions. Properties of these new solutions, which are similar to the Witten bubble of nothing and Sbranes, are discussed. We comment on how these new bubble solutions seem relevant to the tachyon condensation process of nonBPS branes, and remark on their application to cosmological scenarios. Unstable brane configurations which resemble Sbrane type solutions are also discussed.
Gravitational approach to tachyon matter
"... We found a gravity solution of p+1 dimensional extended object with SO(p)×SO(9−p) symmetry which has zero pressure and zero dilaton charge. We expect that this object is a residual tachyon dust after tachyon condensation of brane and antibrane system recently discussed by Sen. We also discuss the H ..."
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We found a gravity solution of p+1 dimensional extended object with SO(p)×SO(9−p) symmetry which has zero pressure and zero dilaton charge. We expect that this object is a residual tachyon dust after tachyon condensation of brane and antibrane system recently discussed by Sen. We also discuss the Hawking temperature and some properties of this object.
SITHEP/TM20 Brane Qball, branonium and brane inflation
, 2004
"... We study the stability of branonium. Contrary to the previous arguments, the global structure of branonium is not stable against spatial fluctuations and decays into local objects. Then we consider the idea of brane Qball. The brane Qballs are produced as the remnants of unstable branonium. Althou ..."
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Cited by 1 (1 self)
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We study the stability of branonium. Contrary to the previous arguments, the global structure of branonium is not stable against spatial fluctuations and decays into local objects. Then we consider the idea of brane Qball. The brane Qballs are produced as the remnants of unstable branonium. Although the brane Qballs are conceptually different from the conventional Qballs, they look similar in some parametric regions. We show how to distinguish brane Qballs from conventional Qballs. 1
COSMIC STRINGS IN BRANE INFLATION AND SUPERSTRING THEORY
, 2004
"... Observable predictions of Superstring theories are rare and important. Recent theoretical advances and upcoming experimental measurements of cosmological physics make the testing of generic predictions of string theories possible. Brane antibrane models of inflation within superstring theory are pr ..."
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Observable predictions of Superstring theories are rare and important. Recent theoretical advances and upcoming experimental measurements of cosmological physics make the testing of generic predictions of string theories possible. Brane antibrane models of inflation within superstring theory are promising as string theory descriptions of the physics of the early universe, and while varied in their construction, they can have the generic and observable consequence that cosmic strings will be abundant in the early universe. This leads to possible detectable effects in the cosmic microwave background, gravitational wave physics, gravitational lensing and pulsar timing. The string theory physics involved in the production of these defects at the phase transition at the end of inflation is reviewed herein. Detailed calculations of cosmic string interactions within string theory are also presented, in order to distinguish these cosmic strings from those in more conventional theories. It is found that cosmic strings are stable and have tensions compatible with current upper bounds and which are detectable in upcoming experiments. Interaction probabilities of these strings are found to be very different from conventional strings, providing the possibility of experimental tests of string theory.
QMULPH0804 Phase Transitions in Separated Dp−1 and antiDp−1 Branes at Finite Temperature
, 802
"... We consider a pair of parallel Dp−1 and antiDp−1 branes in flat space, with a finite separation d along some perpendicular spatial direction and at finite temperature. If this spatial direction is compactified on a circle then by Tduality, the system is equivalent to a DpantiDp pair wrapped aroun ..."
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We consider a pair of parallel Dp−1 and antiDp−1 branes in flat space, with a finite separation d along some perpendicular spatial direction and at finite temperature. If this spatial direction is compactified on a circle then by Tduality, the system is equivalent to a DpantiDp pair wrapped around the dual circle with a constant Wilson line A ≈ d on one of the branes. We focus in particular on the p = 9 case and compute the free energy of this system and study the occurrence of second order phase transitions as both the temperature and Wilson line (braneantibrane separation) are varied. In the limit of vanishing Wilson line we recover the previous results obtained in the literature, whereby the open string vacuum at the origin of the tachyon field T = 0 is stabilized at sufficiently high temperature at which a second order phase transition occurs. For sufficiently large Wilson line, we find new second order phase transitions corresponding to the existence of two minima in the tachyon effective potential at finite temperature and tachyon field value. Entropic arguments suggest that as the system cools, the tachyon is likely to find itself in the minimum that approaches infinity as the temperature vanishes (i.e. the one corresponding to the closed string vacuum), rather than the minimum at T = 0 (corresponding to the open string vacuum).Contents 1
KUNS1831 hepth/0303236 Finite Temperature Systems of BraneAntibrane on a Torus
, 2003
"... In order to study the thermodynamic properties of braneantibrane systems in the toroidal background, we compute the finite temperature effective potential of tachyon T in this system on the basis of boundary string field theory. We first consider the case that all the radii of the target space toru ..."
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In order to study the thermodynamic properties of braneantibrane systems in the toroidal background, we compute the finite temperature effective potential of tachyon T in this system on the basis of boundary string field theory. We first consider the case that all the radii of the target space torus are about the string scale. If the DpDp pair is extended in all the noncompact directions, the sign of the coefficient of T  2 term of the potential changes slightly below the Hagedorn temperature. This means that a phase transition occurs near the Hagedorn temperature. On the other hand, if the DpDp pair is not extended in all the noncompact directions, the coefficient is kept negative, and thus a phase transition does not occur. Secondly, we consider the case that some of the radii of the target space torus are much larger than the string scale and investigate the behavior of the potential for each value of the radii and the total energy. If the DpDp pair is extended in all the noncompact directions, a phase transition occurs for large enough total energy. 1