TY - JOUR

T1 - Closed strings as imaginary D-branes

AU - Gaiotto, Davide

AU - Itzhaki, Nissan

AU - Rastelli, Leonardo

N1 - Funding Information:
We thank C. Callan, A. Hashimoto, I. Klebanov, H. Liu, J. Maldacena, J. McGreevy, H. Ooguri, A. Sen, C. Vafa and H. Verlinde for discussions. This material is based upon work supported by the National Science Foundation under Grant No. PHY 9802484. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Science Foundation.

PY - 2004/6/7

Y1 - 2004/6/7

N2 - 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-transition à 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.

AB - 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-transition à 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.

UR - http://www.scopus.com/inward/record.url?scp=2342658481&partnerID=8YFLogxK

U2 - 10.1016/j.nuclphysb.2004.03.017

DO - 10.1016/j.nuclphysb.2004.03.017

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AN - SCOPUS:2342658481

VL - 688

SP - 70

EP - 100

JO - Nuclear Physics B

JF - Nuclear Physics B

SN - 0550-3213

IS - 1-2

ER -