A5004390635- Cosmology and Gravitation Theories
- Black Holes and Theoretical Physics
- Galaxies: Formation, Evolution, Phenomena
- Particle physics theoretical and experimental studies
- Dark Matter and Cosmic Phenomena
- Algebraic Geometry and Number Theory
- Geometry and complex manifolds
- Geophysics and Gravity Measurements
- Noncommutative and Quantum Gravity Theories
- Computational Physics and Python Applications
- Advanced Algebra and Geometry
- Advanced Combinatorial Mathematics
- Solar and Space Plasma Dynamics
- Economic Theory and Policy
- Pulsars and Gravitational Waves Research
- Stochastic processes and financial applications
- Quantum Chromodynamics and Particle Interactions
- Random Matrices and Applications
- Homotopy and Cohomology in Algebraic Topology
- Geometric and Algebraic Topology
- Earth Systems and Cosmic Evolution
- Topological and Geometric Data Analysis
- Historical Economic and Social Studies
- Particle Accelerators and Free-Electron Lasers
- Algorithms and Data Compression
Cornell University
2015-2024
General Atomics (United States)
2024
Physical Sciences (United States)
2020
Princeton University
2006-2008
Stanford University
2003-2006
We investigate the embedding of brane inflation into stable compactifications string theory. At first sight a warped compactification geometry seems to produce naturally flat inflaton potential, evading one well-known difficulty brane-antibrane scenarios. Careful consideration closed moduli reveals further obstacle: superpotential stabilization volume typically modifies potential and renders it too steep for inflation. discuss non-generic conditions under which this problem does not arise....
Wrapped branes in string compactifications introduce a monodromy that extends the field range of individual closed-string axions to beyond Planck scale. Furthermore, approximate shift symmetries system naturally control corrections axion potential. This suggests general mechanism for chaotic inflation driven by monodromy-extended axions. We systematically analyze this possibility and show is compatible with moduli stabilization can be realized many types compactifications, including warped...
The past two decades have seen transformative advances in cosmology and string theory. Observations of the cosmic microwave background revealed strong evidence for inflationary expansion very early universe, while new insights about compactifications theory led to a deeper understanding inflation framework that unifies quantum mechanics general relativity. Written by leading researchers field, this complete accessible volume provides modern treatment its connections elementary particle After...
We study the CMB observables in axion monodromy inflation. These well-motivated scenarios for inflation string theory have monomial potentials over super-Planckian field ranges, with superimposed sinusoidal modulations from instanton effects. Such periodic of potential can drive resonant enhancements correlation functions cosmological perturbations, characteristic amplitude as a function wavenumber. give an analytical result scalar power spectrum this class models, and we determine limits...
We summarize the utility of precise cosmic microwave background (CMB) polarization measurements as probes physics inflation. focus on prospects for using CMB to differentiate various inflationary mechanisms. In particular, a detection primordial B‐mode would demonstrate that inflation occurred at very high energy scale, and inflaton traversed super‐Planckian distance in field space. explain how such or constraint illuminate aspects Planck scale. Moreover, can constrain scale‐dependence...
We derive a microscopic bound on the maximal field variation of inflaton during warped D-brane inflation. By result Lyth, this implies an upper limit amount gravitational waves produced show that detection at level $r>0.01$ would falsify slow roll In DBI (Dirac-Born-Infeld) inflation, detectable tensors may be possible in special compactifications, provided $r$ decreases rapidly also for case inflation with quadratic potential, current observational constraints imply strong bounds five-form flux.
We present a detailed analysis of an explicit model warped D-brane inflation, incorporating the effects moduli stabilization. consider potential for D3-brane motion in conifold background that includes fluxes and holomorphically-embedded D7-branes involved Although significantly modify inflaton potential, they do not correct quadratic term hence cause uniform change slow-roll parameter eta. Nevertheless, we simple example based on Kuperstein embedding D7-branes, z_1=constant, which can be...
We investigate whether explicit models of warped D-brane inflation are possible in string compactifications. To this end, we study the potential for D3-brane motion a conifold that includes holomorphically embedded D7-branes involved moduli stabilization. The presence significantly modifies inflaton potential. construct an example based on very simple and symmetric embedding due to Kuperstein, z1= const, which it is fine-tune so slow-roll can occur. resulting model rather delicate: occurs...
Flux couplings to string theory axions yield super-Planckian field ranges along which the axion potential energy grows. At same time, other aspects of physics remain essentially unchanged these large displacements, respecting a discrete shift symmetry with sub-Planckian period. After general overview this monodromy effect and its application large-field inflation, we present new classes specific models monomial potentials $\mu^{4-p}\phi^p$. A key simplification in is that inflaton plays...
We provide a pedagogical overview of inflation in string theory. Our theme is the sensitivity to Planck-scale physics, which we argue provides both primary motivation and central theoretical challenge for subject. illustrate these issues through two case studies inflationary scenarios theory: warped D-brane axion monodromy inflation. Finally, indicate how future observations can test
We give a comprehensive treatment of the scalar potential for D3-brane in warped conifold region compactification with stabilized moduli. By studying general ultraviolet perturbations supergravity, we systematically incorporate 'compactification effects' sourced by supersymmetry breaking compact space. Significant contributions to potential, including leading term infrared, arise from imaginary anti-self-dual (IASD) fluxes. For an arbitrary Calabi-Yau cone, determine most IASD fluxes terms...
We study the topological properties of Calabi-Yau threefold hypersurfaces at large h1,1. obtain two million threefolds X by triangulating polytopes from Kreuzer-Skarke list, including all with 240 ≤ h1,1 491. show that Kähler cone is very narrow h1,1, and as a consequence, control α′ expansion in string compactifications on correlated presence ultralight axions. If every effective curve has volume ≥ 1 units, then typical volumes irreducible curves divisors, itself, scale (h1,1)p, 3 ≲ p 7...
Several recent works [1-3] have claimed that the Weak Gravity Conjecture (WGC) excludes super-Planckian displacements of axion fields, and hence large-field inflation, in absence monodromy. We argue theories with N ≫ 1 axions, diameters $$ \mathcal{D} are readily allowed by WGC. clarify non-trivial relationship between kinetic matrix K — unambiguously defined its form a Minkowski-reduced basis diameter fundamental domain, emphasizing general is not solely determined eigenvalues f 2 ≤ ⋅ K:...
We describe a method for finding flux vacua of type IIB string theory in which the Gukov-Vafa-Witten superpotential is exponentially small. present an example with ${W}_{0}\ensuremath{\approx}2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$ on orientifold Calabi-Yau hypersurface $({h}^{1,1},{h}^{2,1})=(2,272)$, at large complex structure and weak coupling.
The authors discuss type IIB string theory realizations of Kim-Nilles-Peloso (KNP) multiple axion inflation, which provides a super-Planckian effective decay constant, necessary for UV stable realistic slow roll inflation.
We perform an extensive analysis of the statistics axion masses and interactions in compactifications type IIB string theory, we show that black hole superradiance excludes some regions Calabi-Yau moduli space. Regardless cosmological model, a theory with whose mass falls superradiant band can be probed by measured properties astrophysical holes, unless self-interaction is large enough to disrupt formation condensate. study ensemble on hypersurfaces, $1 \leq h^{1,1} 491$ closed axions,...
A bstract We construct supersymmetric AdS 4 vacua of type IIB string theory in compactifications on orientifolds Calabi-Yau threefold hypersurfaces. first find explicit and quantized fluxes for which the superpotential takes form proposed by Kachru, Kallosh, Linde, Trivedi. Given very mild assumptions numerical values Pfaffians, these admit all moduli are stabilized at weak coupling. By computing high-degree Gopakumar-Vafa invariants we give strong evidence that α ′ expansion is likewise...
We construct a supersymmetric vacuum of string theory in which the magnitude energy is $<{10}^{\ensuremath{-}123}$ Planck units. The mechanism that we introduce generates well-controlled exponential hierarchy from an appropriate choice quantized parameters superpotential. Our approach provides new angle on cosmological constant problem.
We show that the strong CP problem is solved in a large class of compactifications string theory. The Peccei-Quinn mechanism solves if CP-breaking effects ultraviolet completion gravity and QCD are small compared to CP-preserving axion potential generated by low-energy instantons. characterize both classes effects. To understand quantum gravitational effects, we consider an ensemble flux type IIB theory on orientifolds Calabi-Yau hypersurfaces geometric regime, taking simple model D7-branes....
Abstract We study axion-photon couplings in compactifications of type IIB string theory. find that these are systematically suppressed compared to the inverse axion periodicity, as a result two effects. First, QED theta angle for mass eigenstates light scale set by stringy instantons on cycle supporting QED. Second, with many axions intersection matrix is sparse, making kinetic mixing weak. resulting phenomenology an ensemble 200,000 toy models constructed from Kreuzer-Skarke database up...