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Investigating Inflation in Type IIA

Description: We prove that inflation is forbidden in the most well understood class of semi-realistic type IIA string compactifications: Calabi-Yau compactifications with only standard NS-NS 3-form flux, R-R fluxes, D6-branes and O6-planes at large volume and small string coupling. With these ingredients, the first slow-roll parameter satisfies {epsilon} {ge} 27/13 whenever V > 0, ruling out both inflation (including brane/anti-brane inflation) and de Sitter vacua in this limit. Our proof is based on the… more
Date: December 14, 2007
Creator: Hertzberg, Mark P.; /MIT; Kachru, Shamit; /Stanford U., Phys. Dept. /SLAC; Taylor, Washington; Tegmark, Max et al.
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Holographic Systematics of D-brane Inflation

Description: We provide a systematic treatment of possible corrections to the inflaton potential for D-brane inflation in the warped deformed conifold. We consider the D3-brane potential in the presence of the most general possible corrections to the throat geometry sourced by coupling to the bulk of a compact Calabi-Yau space. This corresponds to the potential on the Coulomb branch of the dual gauge theory, in the presence of arbitrary perturbations of the Lagrangian. The leading contributions arise from p… more
Date: November 5, 2008
Creator: Baumann, Daniel; /Harvard U., Phys. Dept. /Princeton U.; Dymarsky, Anatoly; /Stanford U., Phys. Dept.; Kachru, Shamit; /Stanford U., Phys. Dept. /SLAC et al.
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Simple Stringy Dynamical SUSY Breaking

Description: We present simple string models which dynamically break supersymmetry without non-Abelian gauge dynamics. The Fayet model, the Polonyi model, and the O'Raifeartaigh model each arise from D-branes at a specific type of singularity. D-brane instanton effects generate the requisite exponentially small scale of supersymmetry breaking.
Date: August 8, 2007
Creator: Aharony, Ofer; /Weizmann Inst. /Stanford U., Phys. Dept. /SLAC; Kachru, Shamit; Silverstein, Eva & /Stanford U., Phys. Dept. /SLAC
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Gravity Duals of Lifshitz-Like Fixed Points

Description: We find candidate macroscopic gravity duals for scale-invariant but non-Lorentz invariant fixed points, which do not have particle number as a conserved quantity. We compute two-point correlation functions which exhibit novel behavior relative to their AdS counterparts, and find holographic renormalization group flows to conformal field theories. Our theories are characterized by a dynamical critical exponent z, which governs the anisotropy between spatial and temporal scaling t {yields} {lambd… more
Date: November 5, 2008
Creator: Kachru, Shamit; /Stanford U., Phys. Dept. /SLAC; Liu, Xiao; Phys., /Perimeter Inst. Theor.; Mulligan, Michael & /Stanford U., Phys. Dept. /SLAC
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A Gravity Dual of Metastable Dynamical Supersymmetry Breaking

Description: Metastable, supersymmetry-breaking configurations can be created in flux geometries by placing antibranes in warped throats. Via gauge/gravity duality, such configurations should have an interpretation as supersymmetry-breaking states in the dual field theory. In this paper, we perturbatively determine the asymptotic supergravity solutions corresponding to D3-brane probes placed at the tip of the cascading warped deformed conifold geometry, which is dual to an SU(N+M) x SU(N) gauge theory. The … more
Date: February 4, 2008
Creator: DeWolfe, Oliver; U., /Colorado; Kachru, Shamit; Mulligan, Michael & /Stanford U., Phys. Dept. /SLAC
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New Sources of Gravitational Waves During Inflation

Description: We point out that detectable inflationary tensor modes can be generated by particle or string sources produced during inflation, consistently with the requirements for inflation and constraints from scalar fluctuations. We show via examples that this effect can dominate over the contribution from quantum fluctuations of the metric, occurring even when the inflationary potential energy is too low to produce a comparable signal. Thus a detection of tensor modes from inflation does not automatical… more
Date: February 15, 2012
Creator: Senatore, Leonardo; Silverstein, Eva; /Stanford U., Phys. Dept. /SLAC; Zaldarriaga, Matias & /Princeton, Inst. Advanced Study
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Deconfinement in Yang-Mills Theory through Toroidal Compactification

Description: We introduce field theory techniques through which the deconfinement transition of four-dimensional Yang-Mills theory can be moved to a semi-classical domain where it becomes calculable using two-dimensional field theory. We achieve this through a double-trace deformation of toroidally compactified Yang-Mills theory on R{sup 2} x S{sub L}{sup 1} x S{sub {beta}}{sup 1}. At large N, fixed-L, and arbitrary {beta}, the thermodynamics of the deformed theory is equivalent to that of ordinary Yang-Mil… more
Date: August 12, 2011
Creator: Simic, Dusan; Unsal, Mithat & /Stanford U., Phys. Dept. /SLAC
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New Dualities in Supersymmetric Chiral Gauge Theories

Description: We analyze the phase structure of supersymmetric chiral gauge theories with gauge group SU(N), an antisymmetric, and F {le} N + 3 flavors, in the presence of a cubic superpotential. When F = N + 3 the theory flows to a superconformal fixed point in the infrared, and new dual descriptions of this theory are uncovered. The theory with odd N admits a self-dual magnetic description. For general N, we find an infinite family of magnetic dual descriptions, characterized by arbitrarily large gauge gro… more
Date: August 15, 2011
Creator: Craig, Nathaniel; /Princeton, Inst. Advanced Study /Rutgers U., Piscataway; Essig, Rouven; Hook, Anson; Torroba, Gonzalo & /Stanford U., Phys. Dept. /SLAC
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D-brane Instantons in Type II String Theory

Description: We review recent progress in determining the effects of D-brane instantons in N=1 supersymmetric compactifications of Type II string theory to four dimensions. We describe the abstract D-brane instanton calculus for holomorphic couplings such as the superpotential, the gauge kinetic function and higher fermionic F-terms. This includes a discussion of multi-instanton effects and the implications of background fluxes for the instanton sector. Our presentation also highlights, but is not restricte… more
Date: June 19, 2009
Creator: Blumenhagen, Ralph; /Munich, Max Planck Inst.; Cvetic, Mirjam; U., /Pennsylvania; Kachru, Shamit; /Stanford U., Phys. Dept. /SLAC et al.
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Adventures in Holographic Dimer Models

Description: We abstract the essential features of holographic dimer models, and develop several new applications of these models. Firstly, semi-holographically coupling free band fermions to holographic dimers, we uncover novel phase transitions between conventional Fermi liquids and non-Fermi liquids, accompanied by a change in the structure of the Fermi surface. Secondly, we make dimer vibrations propagate through the whole crystal by way of double trace deformations, obtaining nontrivial band structure.… more
Date: August 12, 2011
Creator: Kachru, Shamit; /Stanford U., Phys. Dept. /SLAC; Karch, Andreas; /Washington U., Seattle; Yaida, Sho & /Stanford U., Phys. Dept.
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Effective Field Theory of Fractional Quantized Hall Nematics

Description: We present a Landau-Ginzburg theory for a fractional quantized Hall nematic state and the transition to it from an isotropic fractional quantum Hall state. This justifies Lifshitz-Chern-Simons theory - which is shown to be its dual - on a more microscopic basis and enables us to compute a ground state wave function in the symmetry-broken phase. In such a state of matter, the Hall resistance remains quantized while the longitudinal DC resistivity due to thermally-excited quasiparticles is anisot… more
Date: June 6, 2012
Creator: Mulligan, Michael; /MIT, LNS; Nayak, Chetan; /Station Q, UCSB; Kachru, Shamit & /Stanford U., Phys. Dept. /SLAC
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Type IIA Moduli Stabilization

Description: No Description Available.
Date: June 20, 2005
Creator: DeWolfe, Oliver; U., /Princeton; Giryavets, Alexander; Kachru, Shamit; /Stanford U., Phys. Dept. /SLAC; Taylor, Washington et al.
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Exact Attractive Non-BPS STU Black Holes

Description: We develop some properties of the non-BPS attractive STU black hole. Our principle result is the construction of exact solutions for the moduli, the metric and the vectors in terms of appropriate harmonic functions. In addition, we find a spherically-symmetric attractor carrying p{sup 0} (D6 brane) and q{sub a} (D2 brane) charges by solving the non-BPS attractor equation (which we present in a particularly compact form) and by minimizing an effective black hole potential. Finally, we make an ar… more
Date: July 18, 2006
Creator: Kallosh, Renata; /Stanford U., Phys. Dept.; Sivanandam, Navin; Soroush, Masoud & /Stanford U., Phys. Dept. /SLAC
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Black Hole Entropy and Fourie-Mukai Transform

Description: We propose a microscopic CFT description of magnetically charged black holes in IIA compactifications on elliptic fibrations based on the Fourier-Mukai transform. The physical derivation of this model involves a chain of string duality transformations including the 4D/5D black hole correspondence. We compute the asymptotic behavior of the microstate degeneracy in a certain limit of large charges and show that it agrees with the macroscopic entropy formula. An interesting aspect of this setup is… more
Date: December 4, 2006
Creator: Bena, Iosif; /Saclay; Diaconescu, Duiliu-Emanuel; /Rutgers U., Piscataway; Florea, Bogdan & /Stanford U., Phys. Dept. /SLAC
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Analysis Methods for Milky Way Dark Matter Satellite Detection

Description: The Gamma Ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT) Dark Matter and New Physics Working group has been developing approaches for the indirect detection of in situ annihilation of dark matter. Our work has assumed that a significant component of dark matter is a new type of Weakly Interacting Massive Particle (WIMP) in the 100GeV mass range. The annihilation of two WIMPs results in the production of a large number of high energy gamma rays (>1GeV) that can be well meas… more
Date: October 19, 2007
Creator: Wang, Ping; Wai, Larry; Bloom, Elliott & /Stanford U., Phys. Dept. /SLAC
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A Maximally Supersymmetric Kondo Model

Description: We study the maximally supersymmetric Kondo model obtained by adding a fermionic impurity to N = 4 supersymmetric Yang-Mills theory. While the original Kondo problem describes a defect interacting with a free Fermi liquid of itinerant electrons, here the ambient theory is an interacting CFT, and this introduces qualitatively new features into the system. The model arises in string theory by considering the intersection of a stack of M D5-branes with a stack of N D3-branes, at a point in the D3 … more
Date: February 17, 2012
Creator: Harrison, Sarah; Kachru, Shamit; Torroba, Gonzalo & /Stanford U., Phys. Dept. /SLAC
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Generalized Attractor Points in Gauged Supergravity

Description: The attractor mechanism governs the near-horizon geometry of extremal black holes in ungauged 4D N=2 supergravity theories and in Calabi-Yau compactifications of string theory. In this paper, we study a natural generalization of this mechanism to solutions of arbitrary 4D N=2 gauged supergravities. We define generalized attractor points as solutions of an ansatz which reduces the Einstein, gauge field, and scalar equations of motion to algebraic equations. The simplest generalized attractor geo… more
Date: August 15, 2011
Creator: Kachru, Shamit; /Stanford U., Phys. Dept. /SLAC; Kallosh, Renata; /Stanford U., Phys. Dept.; Shmakova, Marina & /KIPAC, Menlo Park /SLAC /Stanford U., Phys. Dept.
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Axions in String Theory

Description: In the context of string theory, axions appear to provide the most plausible solution of the strong CP problem. However, as has been known for a long time, in many string-based models, the axion coupling parameter Fa is several orders of magnitude higher than the standard cosmological bounds. We re-examine this problem in a variety of models, showing that Fa is close to the GUT scale or above in many models that have GUT-like phenomenology, as well as some that do not. On the other hand, in som… more
Date: June 9, 2006
Creator: Svrcek, Peter; /Stanford U., Phys. Dept. /SLAC; Witten, Edward & /Princeton, Inst. Advanced Study
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N-Flation

Description: The presence of many axion fields in four-dimensional string vacua can lead to a simple, radiatively stable realization of chaotic inflation.
Date: August 4, 2005
Creator: Dimopoulos, S.; /Stanford U., Phys. Dept.; Kachru, S.; /Stanford U., Phys. Dept. /SLAC; McGreevy, J.; Wacker, J.G. et al.
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An Index for the Dirac Operator on D3 Brane withBackground Fluxes

Description: We study the problem of instanton generated superpotentials in Calabi-Yau orientifold compactifications directly in type IIB string theory. To this end, we derive the Dirac equation on a Euclidean D3 brane in the presence of background fluxes. We propose an index which governs whether the generation of a superpotential in the effective 4d theory by D3 brane instantons is possible. Applying the formalism to various classes of examples, including the K3 x T{sup 2}/Z{sub 2} orientifold, in the abs… more
Date: August 3, 2005
Creator: Bergshoeff, Eric; U., /Groningen; Kallosh, Renata; /Stanford U., Phys. Dept. /Kyoto U., Yukawa Inst., Kyoto; Kashani-Poor, Amir-Kian; /Stanford U., Phys. Dept. /SLAC et al.
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