14 citations · 17 across the 17 of their papers we have counts for
17 papers
Fermionic cosmic strings in dynamical Chern-Simons gravity
Stephon Alexander, Heliudson Bernardo, Shengyuan Zhang
We investigate topological defects produced by a chiral phase transition in a fermionic ultraviolet completion of dynamical Chern-Simons (dCS) gravity. The model contains a complex…
Four-Fermion Condensates in Curved Spacetimes: A Functional Approach
Stephon Alexander, Heliudson Bernardo, Jiatong Yan
Four-fermion interactions appear in effective descriptions of particle physics, many-body systems, and gravitational theories with fermions. Although the same local operator may en…
Quantum de Sitter and Analytically Continued Chern Simons Theory
Stephon Alexander, Kenneth Blakey
We give a Lefschetz thimble definition of the Chern--Simons--Kodama wavefunctional in Lorentzian self-dual gravity with positive cosmological constant. By complexifying the connect…
A Quantum Gravitational Mechanism for Isotropization of de Sitter Cosmologies
Stephon Alexander, Bruno Alexandre, Daine L. Danielson +1
Today, the observable cosmos exhibits a remarkable degree of isotropy and plausibly began in a nearly isotropic initial state. The properties of the Lorentzian Chern-Simons-Kodama…
A Unified Fermionic Origin for Density-Driven Waterfall Inflation and its Multi-Messenger Signatures
Stephon Alexander, Pisin Chen, Jinglong Liu +3
Inflation is conventionally described by fundamental scalar fields whose microscopic origin remains unknown. We propose a different mechanism in which inflation emerges from fermio…
Quantum Gravity, de Sitter Space, and Normalizability
Stephon Alexander, Heliudson Bernardo, Jacob Kuntzleman +1
We propose a resolution to the longstanding problem of perturbative normalizability in canonical quantum gravity of the Lorentzian Chern-Simons-Kodama (CSK) state with a positive c…
Hybrid Inflation from Fermion Condensate
Stephon Alexander, Pisin Chen, Jinglong Liu +3
We investigate how inflation can emerge from four-fermion interactions generated by spacetime torsion, eliminating the need for additional scalar fields beyond the Standard Model.…
The Cosmological Constant from a Quantum Gravitational -Vacua and the Gravitational Hall Effect
Stephon Alexander, Heliudson Bernardo, Aaron Hui
We provide a new perspective on the cosmological constant by exploring the background-independent Wheeler-DeWitt quantization of general relativity. The Chern-Simons-Kodama state o…
Can weak-gravity, causality-violation arguments constrain modified gravity?
Stephon Alexander, Heliudson Bernardo, Nicolás Yunes
We investigate limitations of causality arguments from flat-spacetime amplitudes, based on the eikonal limit of gravitational scattering, to place constraints on modified gravity.…
Perturbations in pseudo-Nambu-Goldstone Higgs Inflation
Stephon Alexander, Humberto Gilmer, Cooper Niu
Pseudo-Nambu-Goldstone (pNG) Higgs Inflation is a novel approach to relate the Higgs boson and its interaction with Electroweak gauge bosons with cosmic inflation, with the potenti…
Birefringence in fermion-attenuated gravitational wave power spectrum
Jinglong Liu, Stephon Alexander, Antonino Marciano
Within the framework of Chern-Simons gravity, a theory that dynamically violates parity, we analyze the power spectrum of gravitational waves in light of the damping effect due to…
Vacuum Amplification of Chiral Gravitational Waves and the Stochastic Gravitational Wave Background
Stephon Alexander, Heliudson Bernardo, Yiya Selina Li +1
We investigate cosmological vacuum amplification of gravitational waves in dynamical Chern-Simons gravity. We develop a comprehensive framework to compute graviton production induc…
A Dark Matter Fermionic Quantum Fluid from Standard Model Dynamics
Stephon Alexander, Heliudson Bernardo, Humberto Gilmer
We present a model of dark matter as a superconducting fluid of Cooper pairs of right handed neutrinos or of vector-like quarks. The superconducting dark matter is induced by attra…
The Non-triviality of Dynamical Chern-Simons Gravity and the Standard Model
Stephon Alexander, Heliudson Bernardo, Cyril Creque-Sarbinowski
Given the growing interest in gravitational-wave and cosmological parity-violating effects in dynamical Chern-Simons (dCS) gravity, it is crucial to investigate whether the scalar-…
Gravitational Waves in Chern-Simons-Gauss-Bonnet Gravity
Tatsuya Daniel, Leah Jenks, Stephon Alexander
It is known that the four-dimensional effective field theory arising from heterotic string theory is general relativity with both a Chern-Simons and Gauss-Bonnet term. We study the…
A Realist Interpretation of Unitarity in Quantum Gravity
Indrajit Sen, Stephon Alexander, Justin Dressel
Unitarity is a difficult concept to implement in canonical quantum gravity because of state non-normalizability and the problem of time. We take a realist approach based on pilot-w…
What can galaxy shapes tell us about physics beyond the standard model?
Oliver H. E. Philcox, Morgane J. König, Stephon Alexander +1
The shapes of galaxies trace scalar physics in the late-Universe through the large-scale gravitational potential. Are they also sensitive to higher-spin physics? We present a gener…