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Closed string tachyons, flips and conifolds
 JHEP 0603
, 2006
"... hepth/0510104 ..."
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De Sitter Quantum Mechanics and Inflationary Matrix cosmology of Selftuned Universe
"... We observe that the large N world sheet RG in c = 1 matrix model, formulated in [1, 2], with N2 quantum mechanical degrees of freedom at small compactification radius is capable of capturing dimensional mutation. This manifests in deforming the familiar AdS2 quantum mechanics in the minisuperspace W ..."
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We observe that the large N world sheet RG in c = 1 matrix model, formulated in [1, 2], with N2 quantum mechanical degrees of freedom at small compactification radius is capable of capturing dimensional mutation. This manifests in deforming the familiar AdS2 quantum mechanics in the minisuperspace Wheelerde Witt (WdW) cosmology of the 2D quantum gravity, obtained by the large N RG with N quantum mechanical degrees of freedom only, to a modified WdW cosmology describing tunneling to an inflationary de Sitter vacuum and its evolution. The scale fluctuation plays an important role in providing an ansatz for uniquely choosing the initial wave function. We observe that the nonperturbative effects due to the N2 quantum mechanical degrees of freedom introduce explicit open string moduli dependence in the wave function via the Hubble scale, which determines the geometry of the true vacuum one tunnels to. The modified WdW equation also captures controlled formation of baby universes of vanishing size that selftunes the de Sitter cosmological constant to be small positive. Contents 1
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"... Use of brand names in this report is for identification purposes only and does not consititute endorsement by the U.S. Geological Survey. For additional information Copies of this report can be ..."
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Use of brand names in this report is for identification purposes only and does not consititute endorsement by the U.S. Geological Survey. For additional information Copies of this report can be
Preprint typeset in JHEP style HYPER VERSION
, 909
"... Loop and surface operators in N = 2 gauge theory and Liouville modular geometry ..."
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Loop and surface operators in N = 2 gauge theory and Liouville modular geometry
The Inside Story:
, 2006
"... We analyze the fate of excitations in regions of closed string tachyon condensate, a question crucial for understanding unitarity in a class of black holes in string theory. First we introduce a simple new example of quasilocal tachyon condensation in a globally stable AdS/CFT background, and review ..."
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We analyze the fate of excitations in regions of closed string tachyon condensate, a question crucial for understanding unitarity in a class of black holes in string theory. First we introduce a simple new example of quasilocal tachyon condensation in a globally stable AdS/CFT background, and review tachyons ’ appearance in black hole physics. Then we calculate forces on particles and fields in a tachyon phase using a field theoretic model with spatially localized exponentially growing time dependent masses. This model reveals two features, both supporting unitary evolution in the bulk of spacetime. First, the growing energy of fields sourced by sets of (real and virtual) particles in the tachyon phase yields outward forces on them, leaving behind only combinations which do not source any fields. Secondly, requiring the consistency of perturbative string theory imposes cancellation of a BRST anomaly, which also yields a restricted set of states. Each of these effects supports the notion of a black hole final state arising from stringtheoretic dynamics replacing the black hole singularity. January
and
, 2007
"... The evolution of supersymmetric Atype Dbranes under the bulk renormalization group flow between two different N = 2 minimal models is studied. Using the LandauGinzburg description we show that a specific set of branes decouples from the infrared theory, and we make detailed predictions for the be ..."
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The evolution of supersymmetric Atype Dbranes under the bulk renormalization group flow between two different N = 2 minimal models is studied. Using the LandauGinzburg description we show that a specific set of branes decouples from the infrared theory, and we make detailed predictions for the behavior of the remaining branes. The LandauGinzburg picture is then checked against a direct conformal field theory analysis. In particular we construct a natural index pairing which is preserved by the RG flow, and show that the branes that decouple have vanishing index with the surviving branes.
Preprint typeset in JHEP style HYPER VERSION CERNPHTH/2012365 KUNS2431 Rcharge Conservation and More in
"... Abstract: We consider the string theory origin of Rcharge conservation laws in heterotic orbifold compactifications, deriving the corresponding string coupling selection rule for factorizable and nonfactorizable orbifolds, with prime ordered and nonprime ordered point groups. Rcharge conservatio ..."
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Abstract: We consider the string theory origin of Rcharge conservation laws in heterotic orbifold compactifications, deriving the corresponding string coupling selection rule for factorizable and nonfactorizable orbifolds, with prime ordered and nonprime ordered point groups. Rcharge conservation arises due to symmetries among the worldsheet instantons that can mediate the couplings. Among our results is a previously missed nontrivial contribution to the conserved Rcharges from the γphases in nonprime orbifolds, which weakens the Rcharge selection rule. Symmetries among the worldsheet instantons can also lead to additional selection rules for some couplings. We make a similar analysis for Rule 4 or the “torus lattice selection rule”. Moreover, we identify a new string selection rule, that we call Rule 6 or the “coset vector selection rule”.