A5004773670- Cosmology and Gravitation Theories
- Black Holes and Theoretical Physics
- Galaxies: Formation, Evolution, Phenomena
- Climate variability and models
- Noncommutative and Quantum Gravity Theories
- Radio Astronomy Observations and Technology
- Dark Matter and Cosmic Phenomena
- Plant Water Relations and Carbon Dynamics
- Computational Physics and Python Applications
- Astronomy and Astrophysical Research
- Geophysics and Gravity Measurements
- Quantum Chromodynamics and Particle Interactions
- Solar and Space Plasma Dynamics
- Meteorological Phenomena and Simulations
- Earth Systems and Cosmic Evolution
- Astrophysics and Cosmic Phenomena
- History and Developments in Astronomy
- Advanced Text Analysis Techniques
- Gut microbiota and health
- Physical Activity and Health
- Relativity and Gravitational Theory
- Advanced Mathematical Theories and Applications
- Topic Modeling
- Blind Source Separation Techniques
- Exercise and Physiological Responses
University of Chicago
2022-2024
Harvard University
2018-2022
Des Moines University Osteopathic Medical Center
2022
University of Amsterdam
2020-2021
Harvard University Press
2020
Hong Kong University of Science and Technology
2018
University of Hong Kong
2018
University of Cambridge
2015-2016
Scattering amplitudes at weak coupling are highly constrained by Lorentz invariance, locality and unitarity, depend on model details only through constants the particle content of theory. For example, four-particle analytic for contact interactions have simple poles with appropriately positive residues tree-level exchange. In this paper, we develop an understanding inflationary correlators which parallels that flat-space scattering amplitudes. Specifically, study slow-roll inflation...
We study the imprints of massive particles with spin on cosmological correlators. Using framework effective field theory inflation, we classify couplings these to Goldstone boson broken time translations and graviton. show that it is possible generate observable non-Gaussianity within regime validity theory, as long masses are close Hubble scale their interactions break approximate conformal symmetry inflationary background. derive explicit shape functions for scalar tensor bispectra can...
A bstract key insight of the bootstrap approach to cosmological correlations is fact that all correlators slow-roll inflation can be reduced a unique building block — four-point function conformally coupled scalars, arising from exchange massive scalar. Correlators corresponding particles with spin are then obtained by applying spin-raising operator scalar-exchange solution. Similarly, massless external fields derived acting suitable weight-raising operator. In this paper, we present...
We extend the cosmological bootstrap to correlators involving massless particles with spin. In de Sitter space, these are constrained both by symmetries and locality. particular, isometries become conformal on future boundary of spacetime, which reflected in a set Ward identities that must satisfy. solve acting weight-shifting operators scalar seed solutions. Using this approach, we derive three- four-point spin-1 spin-2 fields conformally coupled scalars. Four-point functions arising from...
A bstract Much of the structure cosmological correlators is controlled by their singularities, which in turn are fixed terms flat-space scattering amplitudes. An important challenge to interpolate between singular limits determine full at arbitrary kinematics. This particularly relevant because singularities not directly observable, but can only be accessed analytic continuation. In this paper, we study rational — including those gauge fields, gravitons, and inflaton whose tree level poles...
The analyticity of response functions and scattering amplitudes implies powerful relations between low-energy observables the underlying short-distance dynamics. These ``IR/UV'' are rooted in basic physical principles, such as causality unitarity. In this paper, we seek similar connections inflation, relating cosmological observations to physics responsible for accelerated expansion. We assume that inflationary theory is Lorentz invariant at short distances, but allow nonrelativistic...
Abstract Primordial non-Gaussianities (PNGs) are signatures in the density field that encode particle physics processes from inflationary epoch. Such have been extensively studied using Cosmic Microwave Background, through constraining their amplitudes, f X NL , with future improvements expected large-scale structure surveys; specifically, galaxy correlation functions. We show weak lensing fields can be used to achieve competitive and complementary constraints. This is shown via Ulagam suite...
In this paper, we explore a novel observational signature of gravitational corrections during slow-roll inflation. We study the coupling inflaton field to higher-curvature tensors in models with minimal breaking conformal symmetry. that case, most general correction tensor two-point function is captured by square Weyl tensor. show these scenarios lead tilt power spectrum and hence violation consistency condition. arrive at same conclusion through an analysis perturbation theory.
Inflation may provide unique insight into the physics at highest available energy scales that cannot be replicated in any realistic terrestrial experiment. Features primordial power spectrum are generically predicted a wide class of models inflation and its alternatives, observationally one most overlooked channels for finding evidence non-minimal inflationary models. Constraints from observations cosmic microwave background cover widest range feature frequencies, but sensitive constraints...
We present differential double-copy relations between gluon and graviton three-point functions in ${\mathrm{AdS}}_{d+1}$. introduce a set of operators anti--de Sitter (AdS) that naturally generalize on shell kinematics scattering amplitudes flat space. This provides way to construct AdS correlators by replacing the kinematic variables with corresponding suitably ordering them. By construction, resulting are manifestly conformally invariant, correct flat-space limit exhibit structure.
The representation theory of de Sitter space allows for a category partially massless particles which have no flat analog, but could existed during inflation. We study the couplings these exotic to inflationary perturbations and determine resulting signatures in cosmological correlators. When interact through exchange fields, their correlation functions inherit scalings that cannot be mimicked by extra massive fields. discuss detail squeezed limit tensor-scalar-scalar bispectrum, show...
The hot dense environment of the early universe is known to have produced large numbers baryons, photons, and neutrinos. These extreme conditions may also other long-lived species, including new light particles (such as axions or sterile neutrinos) gravitational waves. effects any such relics can be observed through their unique imprint in cosmic microwave background (CMB), large-scale structure, primordial element abundances, are important determining initial universe. We argue that future...
Massive spinning particles, if present during inflation, lead to a distinctive bispectrum of primordial perturbations, the shape and amplitude which depend on masses spins extra particles. This signal, in turn, leaves an imprint statistical distribution galaxies; particular, as non-vanishing galaxy bispectrum, can be used probe these In this paper, we for first time new theoretical template generated by massive valid general triangle configuration. We then proceed perform Fisher-matrix...
The forthcoming generation of wide-field galaxy surveys will probe larger volumes and densities, thus allowing for a much signal-to-noise ratio higher-order clustering statistics, in particular the bispectrum. Extracting this information, however, is more challenging than using power spectrum due to complex theoretical modeling, as well significant computational cost evaluating bispectrum signal error budget. To overcome these challenges, several proxy statistics have been proposed...
Cosmological fluctuations retain a memory of the physics that generated them in their spatial correlations. The strength correlations varies smoothly as function external kinematics, which is encoded differential equations satisfied by cosmological correlation functions. In this work, we provide broader perspective on origin and structure these equations. As concrete example, study conformally coupled scalar fields power-law cosmology. wavefunction coefficients model have integral...
Angular cosmological correlators are infamously difficult to compute due the highly oscillatory nature of projection integrals. Motivated by recent development on analytic approaches perturbation theory, in this paper we present an efficient method for computing four-point correlations angular space, generalizing previous works lower-point functions. This builds FFTLog algorithm that approximates matter power spectrum as a sum over power-law functions, which makes certain momentum integrals...
Abstract We study the N -point function of density contrast to quadratic order in squeezed limit during matter-dominated (MD) and radiation-dominated (RD) eras synchronous gauge. Since gauge follows free-fall frame observers, equivalence principle dictates that gradient approximation for long-wavelength mode there is only a single, manifestly time-independent consistency relation function. This simple form dictated by initial mapping between local coordinates, unlike Newtonian its...
Inflation predicts B-mode polarization with correlations that span superhorizon scales at recombination. In contrast, the set up by causal sources, such as phase transitions or defects, necessarily vanish on scales. Motivated BICEP2's detection, we consider prospects for measuring inflationary signature in future observations. We explain finite resolution of an experiment and filtering raw data induces a transfer spurious subhorizon power to scales, describe ways correct it. also provide...
Abstract We introduce two kurt-spectra to probe fourth-order statistics of weak lensing convergence maps. Using state-of-the-art numerical simulations, we study the shapes these as a function source redshifts and smoothing angular scales. employ pseudo- C ℓ approach estimate spectra from realistic maps in presence an observational mask noise for stage-IV large-scale structure surveys. compare results against theoretical predictions calculated using FFTLog formalism, find that simple...
Scattering amplitudes at weak coupling are highly constrained by Lorentz invariance, locality and unitarity, depend on model details only through constants particle content. In this paper, we develop an understanding of inflationary correlators which parallels that flat-space scattering amplitudes. Specifically, study slow-roll inflation with couplings to extra massive particles, for all controlled approximate conformal symmetry the boundary spacetime. After classifying possible contact...
With the advent of a new generation cosmological experiments that will provide high-precision measurements cosmic microwave background (CMB) and galaxies in large-scale structure, it is pertinent to examine potential performing joint analysis multiple probes. In this paper, we study information content contained one-loop power spectra tree bispectra cross-correlated with CMB lensing. We use FFTLog method compute angular correlations spherical harmonic space, applicable for wide angles can be...
A bstract We present a classification of conformally-invariant three-point tensor structures in d dimensions that parallels the three-particle scattering amplitudes + 1 dimensions. Using set canonically-normalized weight-shifting operators, we construct basis involving conserved currents or stress tensors and non-conserved spinning directly from their amplitude counterparts. As an application, also examine conformal block expansion four-point functions external this basis. Our results can be...
We present a new method for evaluating tensor integrals in the large-scale structure. Decomposing $\Lambda$CDM-like universe into finite sum of scaling universes using FFTLog, we can recast loop biased tracers structure as certain quantum field theory. While rotational symmetry is spontaneously broken by fixed reference frame which are observed, structures still be organized to respect underlying symmetry. Projecting integrands onto spherical harmonics, problem effectively reduces evaluation...