A5062935722- Cosmology and Gravitation Theories
- Dark Matter and Cosmic Phenomena
- Galaxies: Formation, Evolution, Phenomena
- Computational Physics and Python Applications
- Black Holes and Theoretical Physics
- Pulsars and Gravitational Waves Research
- Cold Atom Physics and Bose-Einstein Condensates
- Radio Astronomy Observations and Technology
- Solar and Space Plasma Dynamics
- Astrophysics and Cosmic Phenomena
- Geophysics and Gravity Measurements
- Astronomy and Astrophysical Research
- Relativity and Gravitational Theory
- History and Developments in Astronomy
- Particle physics theoretical and experimental studies
- Advanced Thermodynamics and Statistical Mechanics
- Gamma-ray bursts and supernovae
- Astrophysics and Star Formation Studies
- Astrophysical Phenomena and Observations
- Quantum Electrodynamics and Casimir Effect
- Atomic and Subatomic Physics Research
- Space Science and Extraterrestrial Life
- Nonlinear Photonic Systems
- Physics of Superconductivity and Magnetism
- Earth Systems and Cosmic Evolution
Rice University
2016-2024
University of Cambridge
2013-2016
Massachusetts Institute of Technology
2010-2015
Yale University
2010
Stanford University
2006-2008
Kavli Institute for Particle Astrophysics and Cosmology
2006-2008
Brookhaven National Laboratory
2002
We present a detailed investigation of subdominant oscillating scalar field [``early dark energy'' (EDE)] in the context resolving Hubble tension. Consistent with earlier work, but without relying on fluid approximations, we find that frozen due to friction until ${\mathrm{log}}_{10}({z}_{c})\ensuremath{\sim}3.5$, reaching ${\ensuremath{\rho}}_{\mathrm{EDE}}({z}_{c})/{\ensuremath{\rho}}_{\mathrm{tot}}\ensuremath{\sim}10%$ and diluting faster than matter afterwards, can bring cosmic microwave...
The origin of hot Jupiters—gas giant exoplanets orbiting very close to their host stars—is a long-standing puzzle. Planet formation theories suggest that such planets are unlikely have formed in situ but instead may at large orbital separations beyond the snow line and migrated inward present orbits. Two competing hypotheses either through interaction with protoplanetary disk during formation, or by disk-free mechanisms as gravitational interactions third body. Observations eccentricities...
Oscillons are massive, long-lived, localized excitations of a scalar field. We show that in large class well-motivated single-field models, inflation is followed by self-resonance, leading to copious oscillon generation and lengthy period domination. These models characterized an inflaton potential which has quadratic minimum shallower than away from the minimum. This set includes both string monodromy supergravity inspired scenarios, good agreement with current central values concordance...
Homogeneous oscillations of the inflaton after inflation can be unstable to small spatial perturbations even without coupling other fields. We show that for potentials $\propto |\phi|^{2n}$ near $|\phi|=0$ and flatter beyond some $|\phi|=M$, condensate lead self-resonance, followed by its complete fragmentation. find non-quadratic minima ($n>1$), shortly backreaction, equation state parameter, $w\rightarrow1/3$. If $M\ll m_{pl}$, radiation domination is established within less than an e-fold...
Abstract CMB-S4—the next-generation ground-based cosmic microwave background (CMB) experiment—is set to significantly advance the sensitivity of CMB measurements and enhance our understanding origin evolution universe. Among science cases pursued with CMB-S4, quest for detecting primordial gravitational waves is a central driver experimental design. This work details development forecasting framework that includes power-spectrum-based semianalytic projection tool, targeted explicitly toward...
We present and employ a new kinematical approach to cosmological ‘dark energy’ studies. construct models in terms of the dimensionless second third derivatives scalefactor a(t) with respect cosmic time t, namely present-day value deceleration parameter q0 jerk parameter, j(t). An elegant feature this parametrization is that all Λ cold dark matter (ΛCDM) have j(t) = 1 (constant), which facilitates simple tests for departures from ΛCDM paradigm. Applying our model three best available sets...
We calculate the equation of state after inflation and provide an upper bound on duration before radiation domination by taking nonlinear dynamics fragmented inflaton field into account. A broad class single-field inflationary models with observationally consistent flattening potential at a scale $M$ away from origin, $V(\phi)\propto |\phi|^{2n}$ near where couplings to other fields are ignored included in our analysis. find that parameter $w\rightarrow 0$ for $n=1$ 1/3$ (after sufficient...
In hierarchical models of structure formation, the first galaxies form in low-mass dark matter potential wells, probing behavior on kiloparsec scales. Even though these objects are below detection threshold current telescopes, future missions will open an observational window into this emergent world. Letter, we investigate how assembled a "fuzzy" (FDM) cosmology where is ultralight ∼10^{-22} eV boson and primordial stars expected to along dense filaments. Using first-of-its-kind...
We study the scalar and tensor perturbations generated by fragmentation of inflaton condensate into oscillons or transients after inflation, using nonlinear classical lattice simulations. Without including backreaction metric perturbations, we find that magnitude never exceeds a few $\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$, whereas maximal strength gravitational wave signal today is $\mathcal{O}({10}^{\ensuremath{-}9})$ for standard postinflationary expansion histories....
In this white paper, we discuss the prospects for characterizing and identifying dark matter using gravitational waves, covering a wide range of candidate types signals. We argue that present upcoming wave probes offer unprecedented opportunities unraveling nature identify most urgent challenges open problems with aim encouraging strong community effort at interface between these two exciting fields research.
At the end of inflation, inflaton field decays into an initially nonthermal population relativistic particles which eventually thermalize. We consider production dark matter from this plasma, focusing on prethermal phase. find that for a cross section $\sigma(E)\sim E^n$ with $n> 2$, present abundance is produced during phase its progenitors. For $n\le entropy reheating makes contribution to subdominant compared thermally. As specific examples, we verify irrelevant gravitino in low scale...
We investigate the formation, gravitational clustering, and interactions of solitons in a self-interacting, nonrelativistic scalar field an expanding universe. Rapid formation large number is driven by attractive self-interactions field, whereas slower clustering forces. Driven closer together gravity, we see rich plethora dynamics soliton ``gas'' including mergers, scatterings, binaries. The numerical simulations are complemented analytic calculations estimates (i) relevant instability...
ABSTRACT Bose–Einstein condensate dark matter (BECDM, also known as fuzzy matter) is motivated by fundamental physics and has recently received significant attention a serious alternative to the established cold (CDM) model. We perform cosmological simulations of BECDM gravitationally coupled baryons investigate structure formation at high redshifts (z ≳ 5) for boson mass m = 2.5 × 10−22 eV, exploring dynamical effects its wavelike nature on cosmic web first galaxies. Our are directly...
We numerically investigate the gravitational waves generated by head-on collision of equal-mass, self-gravitating, real scalar field solitons (oscillatons) as a function their compactness $\mathcal{C}$. show that there exist three different possible outcomes for such collisions: (1) an excited stable oscillaton low $\mathcal{C}$, (2) merger and formation black-hole intermediate (3) pre-merger collapse both oscillatons into individual black-holes large For (1), excited, aspherical continues...
Cosmic inflation provides a window to the highest energy densities accessible in nature, far beyond those achievable any realistic terrestrial experiment. Theoretical insights into inflationary era and its observational probes may therefore shed unique light on physical laws underlying our universe. This white paper describes current theoretical understanding of era, with focus statistical properties primordial fluctuations. In particular, we survey targets for three important signatures...
We investigate the differences in small-scale structure of vector dark matter (VDM) and scalar (SDM) using 3+1 dimensional simulations single/multicomponent Schr\"{o}dinger-Poisson system. find that amount wave interference, core-to-halo mass ratio (and its scatter), spin core, as well shape central regions halos can distinguish VDM SDM. Starting with a collection idealized (self-gravitating solitons) an initial condition, we show system dynamically evolves to approximately spherically...
We first show that the effective non-relativistic theory of gravitationally interacting, massive integer-spin fields (spin-$0$, $1$, and $2$ in particular) is described by a $2s+1$ component Schr\"{o}dinger-Poisson action, where $s$ spin field. then construct $s+1$ distinct, supported solitons this from identically polarized plane waves. Such are extremally polarized, with macroscopically large spin, but no orbital angular momentum. These form basis set, out which partially can be...
We investigate cosmological structure formation in Fuzzy Dark Matter (FDM) with an attractive self-interaction (SI) numerical simulations. Such a SI would arise if the FDM boson were ultra-light axion, which has strong CP symmetry-breaking scale (decay constant). Although weak, may be enough to counteract quantum 'pressure' and alter formation. find our simulations that can enhance small-scale formation, soliton cores above critical mass undergo phase transition, transforming from dilute...
We argue that there is a lower bound of order <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:msup><a:mn>10</a:mn><a:mrow><a:mo>−</a:mo><a:mn>19</a:mn></a:mrow></a:msup><a:mtext> </a:mtext><a:mtext> </a:mtext><a:mi>eV</a:mi></a:math> on dark matter mass if it produced after inflation via process with finite correlation length. rely nondetection free-streaming suppression and white-noise enhancement density perturbations as the observational inputs. Published by...
Abstract (Ultra)light spin-1 particles — dark photons can constitute all of matter (DM) and have beyond Standard Model couplings. This lead to a coherent, oscillatory signature in terrestrial detectors that depends on the coupling strength. We provide signal analysis statistical framework for inferring properties such DM by taking into account (i) stochastic (ii) vector nature underlying field, along with (iii) effects due Earth's rotation. Owing equipartition, time scales shorter than...
Oscillons are extremely long lived, oscillatory, spatially localized field configurations that arise from generic initial conditions in a large number of nonlinear theories. With an eye towards their cosmological implications, we investigate properties expanding universe. We (1) provide analytic solution for one-dimensional oscillons (for the models under consideration) and discuss generalization to three dimensions, (2) stability against wavelength perturbations, (3) estimate effects...
It has been recently suggested that oscillons produced in the early universe from certain asymmetric potentials continue to emit gravitational waves for a number of $e$-folds expansion after their formation, leading potentially detectable wave signals. We revisit this claim by conducting convergence study using graphics processing unit (GPU)-accelerated lattice simulations and show numerical errors accumulated with time are significant low-resolution scenarios, or scenarios where run-time...
Oscillons are extremely long-lived, spatially-localized field configurations in real-valued scalar theories that slowly lose energy via radiation of waves. Before their eventual demise, oscillons can pass through (one or more) exceptionally stable where decay rate is highly suppressed. We provide an improved calculation the non-trivial behavior rates, and lifetimes oscillons. In particular, our correctly captures existence (or absence) long-lived states for large amplitude a broad class...