Bulletin of the American Physical Society
APS April Meeting 2022
Volume 67, Number 6
Saturday–Tuesday, April 9–12, 2022; New York
Session Y14: Cosmological Inference From Early and Late UniverseRecordings Available
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Sponsoring Units: DAP Chair: Katie Harrington, University of Chicago Room: Soho |
Tuesday, April 12, 2022 1:30PM - 1:42PM |
Y14.00001: Cosmology and Astrophysics from CMB secondary anisotropies Simone Ferraro CMB observations aimed at studying Inflation, Dark Matter and Dark Energy are also a treasure trove of information about the Large Scale Structure between us and the surface of last scattering. I will discuss the synergies between upcoming Large-Scale Structure and Cosmic Microwave Background (CMB) experiments, and describe how information about the late-time Universe is imprinted on the small scale CMB. I will review some of the most important physical effects at play and I will focus on the Sunyaev-Zel'dovich (SZ) effect and weak gravitational lensing, which use the CMB as a "backlight" to image the matter and gas in and around galaxies, as well as the epoch of reionization. I will present recent measurements that shine light on the feedback mechanisms in galaxy formation and that provide a resolution to the "missing baryons" problem. I will also discuss the most stringent cosmological constraints to date from the cross-correlation of CMB lensing and galaxy clustering and review the expected improvements with the next generation of experiments. |
Tuesday, April 12, 2022 1:42PM - 1:54PM |
Y14.00002: A Symmetry of the Cosmological Observables, a Mirror World Dark Sector and the Hubble Constant Tension Fei Ge, Lloyd E Knox, Francis-Yan Cyr-Racine We point out a way to make large changes in cosmological parameters while preserving consistency with measurements of CMB temperature and polarization, relative luminosity distances, and many large-scale structure observables. These large changes are possible due to a previously unnoticed scaling transformation symmetry. Under the assumption of equilibrium recombination, the scaling symmetry is exact under uniform scaling of the photon scattering time scale and the gravitational time scales. The scaling transformation of the gravitational time scales is severely constrained by the FIRAS measurement of the mean density of the CMB today. To circumvent this constraint we use a "mirror world" dark sector which is a dark copy of the photons, baryons, and neutrinos in our model. To enforce the scaling of the photon scattering rate, we alter the primordial helium abundance. Due to the sensitivity to the reaction rates of non-equilibrium evolution, the recombination and big bang nucleosynthesis can break the symmetry. We find the non-equilibrium recombination only very mildly breaks the symmetry while the primordial helium and deuterium abundance measurements place strong constraints on the model. We thus have re-mapped the problem of reconciling a higher H0 with thousands of data points to one of reconciling it with only two. Our work motivates more research for detailed dark sector particle physics models and an observationally-viable way to achieve a higher photon scattering rate. |
Tuesday, April 12, 2022 1:54PM - 2:06PM |
Y14.00003: Dark Sector and Cosmological Neutrinos: The Sejong Hydrodynamical Simulation Suite Graziano Rossi The Sejong Suite is an extensive collection of state-of-the-art high-resolution cosmological hydrodynamical simulations, developed for modeling the dark sector (massive neutrinos, dark radiation, warm dark matter). The resolution can be enhanced up to 110 billion particles in a [100 Mpc/h]3 volume - optimal for the coming generation of cosmological surveys, including the Dark Energy Spectroscopic Instrument (DESI). The suite is grouped into 3 categories, addressing different science targets. In particular, we will focus on the Systematics Suite and present a number of effects that can impact parameter constraints, related to the modeling of additional species or intrinsic to the numerical nature of our simulations. Quantifying and modeling systematics are essential tasks in order to obtain unbiased cosmological parameters and reliable likelihoods and constraints, particularly at high-redshift and at small scales, where baryons play a critical role. Finally, we will highlight the novelty of extended mixed scenarios describing the combined effects of warm dark matter, active and sterile neutrinos. |
Tuesday, April 12, 2022 2:06PM - 2:18PM |
Y14.00004: Testing deviations from general relativity at cosmological scales reveals a new dichotomy between Planck and lensing data Mustapha Ishak, Cristhian Garcia Quintero Phenomenological parameterization of the perturbed Einstein's equations have become an important route to testing General Relativity (GR) at cosmological scales. This is often done by constraining a pair of modified gravity (MG) parameters. We explore here constraints on one MG parameter at a time while fixing the other at its GR value. This allows one to analyze various models while benefiting from a stronger constraining power from the data. We find cases with stronger tension with GR than two-MG-parameter approaches. For example, models with (μ=1, η) and (μ, η=1) exhibit a 3.86-σ and 3.77-σ departure from their GR values when using Planck18+SNe+BAO data. We find no tension with GR for models with the MG parameter Σ fixed to its GR unity value. Using a Bayesian model selection analysis, we find one-parameter MG models that are moderately favored over ΛCDM when using all dataset combinations except Planck CMB Lensing and DES data. Namely, Planck shows a moderate tension with GR that only increases when adding any combination of RSD, SNe, or BAO. However, adding Planck CMB Lensing or DES data respectively diminishes or removes these tensions, which can be attributed to the ability of lensing in constraining the MG parameter Σ. The two overall groups of datasets are found to have a dichotomy when performing consistency tests with GR, which may be due to systematic effects, lack of constraining power, or modelling. These findings warrant further investigation using more precise data from ongoing and future surveys. |
Tuesday, April 12, 2022 2:18PM - 2:30PM |
Y14.00005: Inflaton Effective Potential from Photons for an arbitrary first slow-roll parameter. Sanjib Katuwal, Richard P Woodard, Shun-Pei Miao
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Tuesday, April 12, 2022 2:30PM - 2:42PM |
Y14.00006: Determining the Hubble Constant without the Sound Horizon: Perspectives with future galaxy surveys Gerrit S Farren, Blake D Sherwin, Oliver H Philcox H0 constraints from galaxy surveys are sourced by two standardisable rulers: the sound horizon scale, rs, and the equality scale, keq. Historically analyses have focused on the former scale, but recent work has shown that the latter can also be measured precisely and provides an independent source of information about the expansion rate of the universe. I will discuss how rs-based information can be avoided by removing the typically used prior on the baryon density, and thus the sound-horizon calibration; this comes at the cost of significantly degraded constraints. I will present a new method for marginalisation over rs which allows baryon information to be retained. I will show forecasts with our new method for a Euclid-like spectroscopic survey, contrasting different analysis choices that derive information from the sound horizon scale, the equality scale or a combination thereof. I will also show constraints obtained by applying our approach to the BOSS power spectrum. Consistency of rs- and keq-based H0 measurements provides a valuable generic consistency test of the cosmological model; any inconsistency hints at beyond-ΛCDM physics. I will illustrate this by means of analysing mock data generated within an Early Dark Energy (EDE) cosmology. |
Tuesday, April 12, 2022 2:42PM - 2:54PM |
Y14.00007: Signatures of Multi-field Inflation in LISA Vikas Aragam, Sonia Paban, Sébastien Renaux-Petel, Robert Rosati Unlike light, gravitational waves effectively propagate freely at all times. This will allow gravitational wave detectors like LISA to open a new, deeper window into the early universe. Cosmic inflation and other primordial dynamics could source a stochastic background of gravitational waves (SGWB) in the LISA band. |
Tuesday, April 12, 2022 2:54PM - 3:06PM |
Y14.00008: Evidence of the fine-structure constant in H0-tension: H0 = (73.37 ± 0.54) km s-1 Mpc-1 associated with unstable de Sitter in the future Maurice Van Putten Modern precision measurements of the Hubble expansion H(z) introduce two integral constraints on background models derived from early and late-time cosmology, based on Planck observations of the BAO and, respectively, H0, here normalized to ΛCDM. For H(z) coupled to non-local dark energy Λ = (1 – q)H2 of zero wave-number modes of cosmological spacetime with deceleration parameter q(z). We infer a coupling constant g < 1 for H0 in tension with ΛCDM associated with a de Sitter instability in the future consistent with the swampland conjectures. Results from the Local Distance Ladder give g ≃ 1 - ξα with ξ = 0.49 ± 0.10. This points to H0 = (73.37± 0.54) km s-1 Mpc-1 for ξ = 1/2, anticipating (73.30±1.04) km s-1 Mpc-1 of Riess at al. arXiv:2112.04510v1 (2021). This may serve as a first observational hint of quantum cosmology, breaking T-duality in the Friedmann scale factor a(t) to the same order. (van Putten, 2021, PLB 823 136737.) |
Tuesday, April 12, 2022 3:06PM - 3:18PM |
Y14.00009: Results from the first all-sky search for boson clouds around spinning black holes using LIGO O3 data Andrew Miller We present results from the first all-sky search tailored for long-duration, quasi-monochromatic gravitational-wave signals emitted by ultralight scalar boson clouds around spinning black holes using data from the third observing run of Advanced LIGO. Our search spans gravitational-wave frequencies of 20-610 Hz, and optimizes the choice of the analysis parameters to account for uncertainties in the expected frequency evolution of the signal. We obtain a few outliers that are followed up in detail using two methods, one well-suited for almost monochromatic signals, and another well-adapted for spin-wandering ones. Though we do not find any evidence of gravitational waves, we place stringent upper limits that imply that scalar boson clouds younger than 1000 years, formed by bosons with mass ~1e-13eV, are not likely to exist in our Galaxy, and that show the maximum distance reach as a function of boson mass for a population of black holes with given distributions for mass and spin. |
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