Alexander Westphal
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View article: DeWitt wave functions for de Sitter JT gravity
DeWitt wave functions for de Sitter JT gravity Open
A bstract Jackiw-Teitelboim (JT) gravity in two-dimensional de Sitter space is an intriguing model for cosmological “wave functions of the universe”. Its minisuperspace version already contains all physical information. The size of compact…
View article: Uplifts in the penumbra: features of the moduli potential away from infinite-distance boundaries
Uplifts in the penumbra: features of the moduli potential away from infinite-distance boundaries Open
A bstract The construction of meta-stable four-dimensional de Sitter vacua in type IIB string compactifications represents an important question and an ongoing area of work. There is considerable support both for stringy de Sitter vacua in…
View article: Preheating axions in string cosmology
Preheating axions in string cosmology Open
A bstract Certain inflationary models can feature periods of preheating — an era preceding reheating during which parametric resonance triggers an exponential production of bosons. This non-perturbative process can have significant impact …
View article: End-of-the-world branes and inflationary predictions for rocky and swampy landscapes
End-of-the-world branes and inflationary predictions for rocky and swampy landscapes Open
A bstract Making cosmological predictions in a multiverse is a fundamental theoretical challenge. Assuming that (quasi-)de Sitter vacua are quantum mechanically described by a finite-dimensional Hilbert space, we develop a detailed framewo…
View article: Uplifts in the Penumbra: Features of the Moduli Potential away from Infinite-Distance Boundaries
Uplifts in the Penumbra: Features of the Moduli Potential away from Infinite-Distance Boundaries Open
The construction of meta-stable four-dimensional de Sitter vacua in type IIB string compactifications represents an important question and an ongoing area of work. There is considerable support both for stringy de Sitter vacua in the inter…
View article: Preheating Axions in String Cosmology
Preheating Axions in String Cosmology Open
Certain inflationary models can feature periods of preheating - an era preceding reheating during which parametric resonance triggers an exponential production of bosons. This non-perturbative process can have significant impact on the his…
View article: Neurodivergence and the Rabbit Hole of Extremism: Uncovering Lived Experience
Neurodivergence and the Rabbit Hole of Extremism: Uncovering Lived Experience Open
Background: There have been sporadic and disturbing media accounts of autistic people engaging with extreme ideologies, with comparatively little systematic exploration of this suggested association. Existing research has failed to conside…
View article: Gravitational axiverse spectroscopy: seeing the forest for the axions
Gravitational axiverse spectroscopy: seeing the forest for the axions Open
A bstract We consider inflationary models with multiple spectator axions coupled to dark gauge sectors via Chern-Simons (CS) terms. The energy injection into Abelian gauge fields from the axions engenders a multi-peak profile for scalar an…
View article: Implications of the weak gravity conjecture for de Sitter space decay by flux discharge
Implications of the weak gravity conjecture for de Sitter space decay by flux discharge Open
We examine the implications of the weak gravity conjecture for the mechanisms for discharging cosmological constant via membrane nucleations. Once screening fluxes and membranes which source them enter, and weak gravity bounds are enforced…
View article: Autism spectrum disorder, extremism and risk assessment
Autism spectrum disorder, extremism and risk assessment Open
Background To date, there is no evidence supporting the existence of an association between Autism Spectrum Disorder (ASD) and extremism in the general population. However, there is increasing recognition that several features of ASD may p…
View article: End-of-the-World Branes and Inflationary Predictions for Rocky and Swampy Landscapes
End-of-the-World Branes and Inflationary Predictions for Rocky and Swampy Landscapes Open
Making cosmological predictions in a multiverse is a fundamental theoretical challenge. Assuming that (quasi-)de Sitter vacua are quantum mechanically described by a finite-dimensional Hilbert space, we develop a detailed framework for mak…
View article: Gravitational axiverse spectroscopy: seeing the forest for the axions
Gravitational axiverse spectroscopy: seeing the forest for the axions Open
We consider inflationary models with multiple spectator axions coupled to dark gauge sectors via Chern-Simons (CS) terms. The energy injection into Abelian gauge fields from the axions engenders a multi-peak profile for scalar and tensor s…
View article: Falsifying Anthropics
Falsifying Anthropics Open
We propose using fuzzy axion dark matter to test the anthropic principle. A very light axion can be directly detectable, at least by black hole superradiance effects. The idea then is that gravitational and astrophysical observations can d…
View article: DeWitt wave functions for de Sitter JT gravity
DeWitt wave functions for de Sitter JT gravity Open
Jackiw-Teitelboim (JT) gravity in two-dimensional de Sitter space is an intriguing model for cosmological ``wave functions of the universe'. Its minisuperspace version already contains all physical information. The size of compact slices i…
View article: Implications of Weak Gravity Conjecture for de Sitter Decay by Flux Discharge
Implications of Weak Gravity Conjecture for de Sitter Decay by Flux Discharge Open
We examine implications of the weak gravity conjecture for the mechanisms for discharging cosmological constant via membrane nucleations. Once screening fluxes and membranes which source them enter, and weak gravity bounds are enforced, a …
View article: <scp>ECHO</scp> autism adult healthcare: Training community clinicians to provide quality care for autistic adults
<span>ECHO</span> autism adult healthcare: Training community clinicians to provide quality care for autistic adults Open
Autistic adults experience significant unmet healthcare needs, with opportunities for improvement in both the systems and the practitioners who serve this population. Primary care physicians/practitioners (PCPs) are a natural choice to pro…
View article: Heterotic de Sitter beyond modular symmetry
Heterotic de Sitter beyond modular symmetry Open
A bstract We study the vacua of 4 d heterotic toroidal orbifolds using effective theories consisting of an overall Kähler modulus, the dilaton, and non-perturbative corrections to both the superpotential and Kähler potential that respect m…
View article: Heterotic de Sitter beyond modular symmetry
Heterotic de Sitter beyond modular symmetry Open
We study the vacua of 4d heterotic toroidal orbifolds using effective theories consisting of an overall Kähler modulus, the dilaton, and non-perturbative corrections to both the superpotential and Kähler potential that respect modular inva…
View article: Quantum-mechanical mechanism for reducing the cosmological constant
Quantum-mechanical mechanism for reducing the cosmological constant Open
We exhibit a mechanism that dynamically adjusts the cosmological constant toward 0+. The adjustment is quantum mechanical, discharging the cosmological constant in random discrete steps. It renders de Sitter space unstable and triggers its…
View article: An étude on global vacuum energy sequester
An étude on global vacuum energy sequester Open
Recently two of the authors proposed a mechanism of vacuum energy sequester as a means of protecting the observable cosmological constant from quantum radiative corrections. The original proposal was based on using global Lagrange multipli…
View article: General double monodromy inflation
General double monodromy inflation Open
We revisit the roller-coaster cosmology based on multiple stages of monodromy inflation. Working within the framework of effective flux monodromy field theory, we include the full range of strong coupling corrections to the inflaton sector…
View article: Vulnerability to Ideologically-Motivated Violence Among Individuals With Autism Spectrum Disorder
Vulnerability to Ideologically-Motivated Violence Among Individuals With Autism Spectrum Disorder Open
People with autism spectrum disorder (ASD) are represented among those who espouse extremist thought and have committed violent acts associated with their beliefs. Media often highlight a perpetrator's psychiatric diagnosis following acts …
View article: A Quantum-Mechanical Mechanism for Reducing the Cosmological Constant
A Quantum-Mechanical Mechanism for Reducing the Cosmological Constant Open
We exhibit a mechanism which dynamically adjusts cosmological constant toward $0^+$. The adjustment is quantum-mechanical, discharging cosmological constant in random discrete steps. It renders de Sitter space unstable, and triggers its de…
View article: Thraxions: towards full string models
Thraxions: towards full string models Open
A bstract We elucidate various aspects of the physics of thraxions, ultra-light axions arising at Klebanov-Strassler multi-throats in the compactification space of IIB superstring theory. We study the combined stabilization of Kähler modul…
View article: Very Hairy Inflation
Very Hairy Inflation Open
We revisit the rollercoaster cosmology based on multiple stages of monodromy inflation. Working within the framework of effective flux monodromy field theory, we include the full range of strong coupling corrections to the inflaton sector.…
View article: Double monodromy inflation: Gravitational wave factory for CMB-S4, LiteBIRD, and LISA
Double monodromy inflation: Gravitational wave factory for CMB-S4, LiteBIRD, and LISA Open
We consider a short rollercoaster cosmology based on two stages of monodromy\ninflation separated by a stage of matter domination, generated after the early\ninflaton falls out of slow roll. If the first stage is controlled by a flat\npote…