Tachyon Matter

Sen has recently drawn attention to an exact time-dependent Boundary Conformal Field Theory with the space-time interpretation of brane creation and annihilation. An interesting limit of this BCFT is formally equivalent to an array of D-branes located in imaginary time. This raises the question: what is the meaning of D-branes in imaginary time? The answer we propose is that D-branes in imaginary time define purely closed string backgrounds. In particular we prove that the disk scattering amplitude of m closed strings off an arbitrary configuration of imaginary branes is equivalent to a sphere amplitude with m + 1 closed string insertions. The extra puncture is a specific closed string state, generically normalizable, that depends on the details of the brane configuration. We study in some detail the special case of the array of imaginary D-branes related to Sen's BCFT and comment on its space-time interpretation. We point out that a certain limit of our set-up allows to study classical black hole creation and suggests a relation between Choptuik's critical behavior and a phase-transitionà la Gregory-Laflamme. We speculate that open string field theory on imaginary D-branes is dual to string theory on the corresponding closed string background.

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“…This is consistent with the computations in [3], where the stress tensor (related to the graviton one-point function)…”

Section: Discussionsupporting

confidence: 92%

“…This background, however, is not the closed string vacuum, but a specific time-dependent state with non-zero energy. The detailed features of this background are very reminiscent of 'tachyon matter' [3,4].…”

Section: Introductionmentioning

confidence: 99%

Closed strings as imaginary D-branes

2004

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“…Remarkably, after we use the onshell condition E = |P |, we find that the amplitude is a constant times an energy dependent phase. 2 As a result, we find that the rate for the number of particles N = dP 2E |A| 2 diverges logarithmically, and the expectation value for the emitted energy diverges linearly in the UV. This expression also has an IR divergence that is related to the fact that we are dealing with a massless field in 1 + 1 dimensions.…”

Section: Jhep07(2003)045mentioning

confidence: 70%

“…In a series of seminal papers Sen proposed a boundary conformal field theory (BCFT) description of the decay of unstable D-branes [1,2,3]. In the bosonic string theory, the BCFT contains a boundary interaction…”

Section: Introductionmentioning

confidence: 99%

D-brane decay in two-dimensional string theory

Klebanov

Maldacena

Seiberg

2003

J. High Energy Phys.

221

468

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We consider unstable D0-branes of two dimensional string theory, described by the boundary state of Zamolodchikov and Zamolodchikov [36] multiplied by the Neumann boundary state for the time coordinate t. In the dual description in terms of the c = 1 matrix model, this D0-brane is described by a matrix eigenvalue on top of the upside down harmonic oscillator potential. As suggested by McGreevy and Verlinde [25], an eigenvalue rolling down the potential describes D-brane decay. As the eigenvalue moves down the potential to the asymptotic region it can be described as a free relativistic fermion. Bosonizing this fermion we get a description of the state in terms of a coherent state of the tachyon field in the asymptotic region, up to a non-local linear field redefinition by an energy-dependent phase. This coherent state agrees with the exponential of the closed string one-point function on a disk with Sen's marginal boundary interaction for t which describes D0-brane decay.

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“…To obtain the inverse Fourier transform of this expression, it is useful to find the Fourier transform of a delta function δ(r − a) where r ≡ x 2 1 + x 2 2 + x 2 3 , 8) and hence for δ ′ (r − a)…”

Section: D0-brane Chargementioning

confidence: 99%

The shape of nonabelian D-branes

Hashimoto¹

2004

J. High Energy Phys.

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Abstract:We evaluate bulk distribution of energies, pressures and various Dbrane/F-string charges generated by nontrivial matrix configurations in nonabelian D-brane effective field theories, using supergravity source density formulas derived originally in Matrix theory. Off-diagonal elements of worldvolume nonabelian fields, especially transverse scalar fields, induce various interesting bulk structures exhibiting the shape of branes. First, we study the energy distribution of string-brane networks generated in the bulk by the Yang-Mills monopoles and the 1/4 BPS dyons, and confirm force balance of them. An application to the Yang-Mills description of recombination of intersecting D-branes gives results indicating presence of the tachyon matter. Second, we analyse the shape of fuzzy D-branes given by nonabelian scalar fields which are mutually noncommutative. We employ fuzzy S 2 , fuzzy S 4 and fuzzy cylinder/supertube as matrix configurations of N D0-branes representing higher dimensional noncommutative D-branes. We find that in the continuum (large N) limit the D-brane charge distributions become in the expected shape of a sphere or a cylinder with an infinitesimal thickness. However, the distributions found for finite N are difficult to interpret, which leaves a puzzle for a possible dual description in terms of higher dimensional D-branes. A resolution is provided with use of an ordering ambiguity in the charge density formulas.

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Tachyon Matter

Cited by 998 publications

References 20 publications

Closed strings as imaginary D-branes

Closed strings as imaginary D-branes

D-brane decay in two-dimensional string theory

The shape of nonabelian D-branes

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