Benjamin Wallisch
A5080240971- Cosmology and Gravitation Theories
- Dark Matter and Cosmic Phenomena
- Astrophysics and Cosmic Phenomena
- Particle physics theoretical and experimental studies
- Radio Astronomy Observations and Technology
- Computational Physics and Python Applications
- Neutrino Physics Research
- Galaxies: Formation, Evolution, Phenomena
- Geophysics and Gravity Measurements
- Astronomy and Astrophysical Research
- Scientific Research and Discoveries
- Particle Detector Development and Performance
- Spaceflight effects on biology
- Economic Theory and Policy
- Advanced Thermodynamics and Statistical Mechanics
- Quantum Mechanics and Applications
- Quantum Electrodynamics and Casimir Effect
- Earth Systems and Cosmic Evolution
- Solar and Space Plasma Dynamics
- Climate variability and models
- Gamma-ray bursts and supernovae
- High-Energy Particle Collisions Research
University of California, San Diego
2019-2024
The University of Texas at Austin
2023-2024
Stockholm University
2023-2024
Center for Theoretical Physics
2023-2024
Instituto de Física Teórica
2023-2024
Institute for Advanced Study
2019-2024
Princeton University
2023
University of Cambridge
2015-2019
University of Amsterdam
2018-2019
Heidelberg University
2017
Fluctuations in the cosmic neutrino background are known to produce a phase shift acoustic peaks of microwave background. It is through sensitivity this effect that recent CMB data has provided robust detection free-streaming neutrinos. In paper, we revisit anisotropy spectrum as probe new physics. The particularly interesting because its physical origin strongly constrained by analytic properties Green's function gravitational potential. For adiabatic fluctuations, requires modes propagate...
Future cosmic microwave background experiments have the potential to probe density of relativistic species at subpercent level. This sensitivity allows light thermal relics be detected up arbitrarily high decoupling temperatures. Conversely, absence a detection would require extra never been in equilibrium with Standard Model. In this Letter, we exploit feature demonstrate future cosmological observations couplings axions photons, gluons, and charged fermions. many cases, constraints...
Abstract Primordial non-Gaussianity generated by additional fields present during inflation offers a compelling observational target for galaxy surveys. These are of significant theoretical interest since they offer window into particle physics in the inflaton sector. They also violate single-field consistency conditions and induce scale-dependent bias power spectrum. In this paper, we explore particular signal light scalar study prospects measuring it with We find that sensitivities current...
This white paper envisions a revolutionary post-DESI, post-LSST dark energy program based on intensity mapping of the redshifted 21cm emission line from neutral hydrogen at radio frequencies. The proposed survey has unique capability to quadruple volume Universe surveyed by optical programs, provide percent-level measurement expansion history $z \sim 6$, open window explore physics beyond concordance $Λ$CDM model, and significantly improve precision standard cosmological parameters. In...
Oscillatory features in the power spectrum of primordial density fluctuations are an important signature inflationary physics and often tied to origin inflation itself. The authors provide a treatment how search for these distribution galaxies late-time universe. This includes insight that impact nonlinear evolution is tractable problem. As consequence, they able use full statistical currently largest galaxy survey BOSS
Our current understanding of the Universe is established through pristine measurements structure in cosmic microwave background (CMB) and distribution shapes galaxies tracing large scale (LSS) Universe. One key ingredient that underlies cosmological observables field sources observed assumed to be initially Gaussian with high precision. Nevertheless, a minimal deviation from Gaussianityis perhaps most robust theoretical prediction models explain Universe; itis necessarily present even...
Abstract Axions and other light particles appear ubiquitously in physics beyond the Standard Model, with a variety of possible couplings to ordinary matter. Cosmology offers unique probe these as they can thermalize hot environment early universe for any such coupling. For sub-MeV particles, their entropy must leave measurable cosmological signal, usually via effective number relativistic N eff . In this paper, we will revisit constraints on axions pseudo-Nambu-Goldstone bosons Model...
Light thermal relics of the hot big bang, often quantified by parameter Neff, are one primary targets cosmological measurements. At present, energy density in such is constrained to be less than ten percent total radiation. Upcoming cosmic microwave background (CMB) experiments, however, have potential measure radiation at one-percent level, which close well-motivated theoretical targets. In this paper, we explore what degree CMB observations can enhanced future large-scale structure...
Despite numerous efforts, the search for oscillatory signatures in primordial spectra has not produced any convincing evidence feature models to date. We undertake a thorough of sharp features WMAP9 power spectrum and bispectrum as well Planck spectrum. For first time, we carry out searches both simultaneously, employing well-defined look-elsewhere statistics assess significances rigorous manner. Developing efficient methods scan likelihoods features, present results phenomenological bare...
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...
Particle physics today faces the challenge of explaining mystery dark matter, origin matter over anti-matter in Universe, neutrino masses, apparent fine-tuning electro-weak scale, and many other aspects fundamental physics. Perhaps most striking frontier to emerge search for answers involves new at mass scales comparable familiar below GeV-scale, or even radically below, down sub-eV scales, with very feeble interaction strength. New theoretical ideas address questions predict such feebly...
The cosmic neutrino background and other light relics leave distinct imprints in the microwave anisotropies through their gravitational influence. Since neutrinos decoupled from primordial plasma about one second after big bang, they have been free-streaming universe. This induced a characteristic phase shift acoustic peaks as unique signature. In this work, we constrain nature of these relativistic species beyond Standard Model particle physics by establishing two complementary...
Following the pioneering observations with COBE in early 1990s, studies of cosmic microwave background (CMB) have focused on temperature and polarization anisotropies. CMB spectral distortions - tiny departures energy spectrum from that a perfect blackbody provide second, independent probe fundamental physics, reach deep into primordial Universe. The theoretical foundation has seen major advances recent years, which highlight immense potential this emerging field. Spectral property Universe...
The approach to equilibrium from systems far it is a subject of great interest in wide variety problems. authors analyze scalar field theory with large number components study how this happens not only for weak, but also moderate coupling, distributions approaching universal transient behavior.
Cosmological observations offer unique and robust avenues for probing the fundamental nature of dark matter particles-they broadly test a range compelling theoretical scenarios, often surpassing or complementing reach terrestrial other experiments. We discuss observational advancements that will play pivotal role in realizing strong program cosmological searches identity coming decade. Specifically, we focus on measurements cosmic-microwave-background anisotropy spectral distortions, tracers...
We summarize progress made in theoretical astrophysics and cosmology over the past decade areas of interest for coming decade. This Report is prepared as TF09 "Astrophysics Cosmology" topical group summary Theory Frontier part Snowmass 2021 process.
This report summarizes the envisioned research activities as gathered from Snowmass 2021 CF5 working group concerning Dark Energy and Cosmic Acceleration: Dawn Before. The scientific goals are to study inflation search for new physics through precision measurements of relic radiation early universe. this decade (2025-35) constructing operating major facilities developing critical enabling capabilities. CMB-S4 project, a Stage-V spectroscopic survey facility, existing gravitational wave...
Many well-motivated extensions of the Standard Model predict existence new light species that may have been produced in early universe. Prominent examples include axions, sterile neutrinos, gravitinos, dark photons, and more. The gravitational influence relics leaves imprints cosmic microwave background fluctuations, large-scale structure universe primordial element abundances. In this paper, we detail physics cosmological relics, describe how measurements their relic density mass serve as...
The intersection of the cosmic and neutrino frontiers is a rich field where much discovery space still remains. Neutrinos play pivotal role in hot big bang cosmology, influencing dynamics universe over numerous decades cosmological history. Recent studies have made tremendous progress understanding some properties neutrinos, primarily their energy density. Upcoming probes will measure density relativistic particles with higher precision, but could also start probing other spectra. When...