activity
20192026
most citedRefined Bounds on MeV-scale Thermal Dark Sectors from BBN and the CMB

170 citations · 676 across the 24 of their papers we have counts for

collaborators

24 papers

astro-ph.CO2026

Impact of non-Gaussian likelihood on cosmological constraints from the thermal Sunyaev--Zel'dovich power spectrum: a simulation-based inference analysis

Licong Xu, Íñigo Zubeldia, James Alvey +2

The thermal Sunyaev--Zel'dovich (tSZ) power spectrum is a sensitive probe of cosmology and cluster astrophysics, but its statistics are non-Gaussian because the signal receives a s…

astro-ph.CO2026

Detecting Gravitational-Wave Anisotropies with Simulation-Based Inference

Anna-Malin Lemke, Andrea Mitridate, Thomas Konstandin +2

Over the last five years, multiple Pulsar Timing Array (PTA) collaborations have reported mounting evidence for a gravitational-wave background (GWB) at nanohertz frequencies. Meas…

astro-ph.IM2025

Dynamic SBI: Round-free Sequential Simulation-Based Inference with Adaptive Datasets

Huifang Lyu, James Alvey, Noemi Anau Montel +2

Simulation-based inference (SBI) is emerging as a new statistical paradigm for addressing complex scientific inference problems. By leveraging the representational power of deep ne…

astro-ph.IM2025

Simulation-based inference with deep ensembles: Evaluating calibration uncertainty and detecting model misspecification

James Alvey, Carlo R. Contaldi, Mauro Pieroni

Simulation-Based Inference (SBI) offers a principled and flexible framework for conducting Bayesian inference in any situation where forward simulations are feasible. However, vali…

gr-qc2025★ 1 cited

Sequential simulation-based inference for extreme mass ratio inspirals

Philippa S. Cole, James Alvey, Lorenzo Speri +4

Extreme mass-ratio inspirals pose a difficult challenge in terms of both search and parameter estimation for upcoming space-based gravitational-wave detectors such as LISA. Their s…

astro-ph.IM2024

Tests for model misspecification in simulation-based inference: from local distortions to global model checks

Noemi Anau Montel, James Alvey, Christoph Weniger

Model misspecification analysis strategies, such as anomaly detection, model validation, and model comparison are a key component of scientific model development. Over the last few…

gr-qc2024★ 2 cited

Leveraging Time-Dependent Instrumental Noise for LISA SGWB Analysis

James Alvey, Uddipta Bhardwaj, Valerie Domcke +2

Variations in the instrumental noise of the Laser Interferometer Space Antenna (LISA) over time are expected as a result of e.g. scheduled satellite operations or unscheduled glitc…

astro-ph.CO2024★ 38 cited

Dwarf galaxies imply dark matter is heavier than

Tim Zimmermann, James Alvey, David J. E. Marsh +2

It is widely established that a lower bound on the dark matter particle mass, , can be obtained by demanding that the de Broglie wavelength in a given galaxy must be smaller tha…

gr-qc2023

Simulation-based inference for stochastic gravitational wave background data analysis

James Alvey, Uddipta Bhardwaj, Valerie Domcke +2

The next generation of space- and ground-based facilities promise to reveal an entirely new picture of the gravitational wave sky: thousands of galactic and extragalactic binary si…

gr-qc2023★ 8 cited

What to do when things get crowded? Scalable joint analysis of overlapping gravitational wave signals

James Alvey, Uddipta Bhardwaj, Samaya Nissanke +1

The gravitational wave sky is starting to become very crowded, with the fourth science run (O4) at LIGO expected to detect compact object coalescence signals. Da…

astro-ph.IM2023★ 15 cited

Scalable inference with Autoregressive Neural Ratio Estimation

Noemi Anau Montel, James Alvey, Christoph Weniger

In recent years, there has been a remarkable development of simulation-based inference (SBI) algorithms, and they have now been applied across a wide range of astrophysical and cos…

gr-qc2023★ 3 cited

Peregrine: Sequential simulation-based inference for gravitational wave signals

Uddipta Bhardwaj, James Alvey, Benjamin Kurt Miller +2

The current and upcoming generations of gravitational wave experiments represent an exciting step forward in terms of detector sensitivity and performance. For example, key upgrade…

astro-ph.GA2023★ 1 cited

Albatross: A scalable simulation-based inference pipeline for analysing stellar streams in the Milky Way

James Alvey, Mathis Gerdes, Christoph Weniger

Stellar streams are potentially a very sensitive observational probe of galactic astrophysics, as well as the dark matter population in the Milky Way. On the other hand, performing…

hep-ph2022★ 37 cited

No room to hide: implications of cosmic-ray upscattering for GeV-scale dark matter

James Alvey, Torsten Bringmann, Helena Kolesova

The irreducible upscattering of cold dark matter by cosmic rays opens up the intriguing possibility of detecting even light dark matter in conventional direct detection experiments…

hep-ph2021★ 42 cited

Cosmic Neutrino Background Detection in Large-Neutrino-Mass Cosmologies

James Alvey, Miguel Escudero, Nashwan Sabti +1

The Cosmic Neutrino Background (CNB) is a definite prediction of the standard cosmological model and its direct discovery would represent a milestone in cosmology and neutrino phys…

astro-ph.CO2021★ 38 cited

What can CMB observations tell us about the neutrino distribution function?

James Alvey, Miguel Escudero, Nashwan Sabti

Cosmic Microwave Background (CMB) observations have been used extensively to constrain key properties of neutrinos, such as their mass. However, these inferences are typically depe…

hep-ph2021★ 34 cited

Addendum: Refined bounds on MeV-scale thermal dark sectors from BBN and the CMB

Nashwan Sabti, James Alvey, Miguel Escudero +2

Very recently, the LUNA collaboration has reported a new measurement of the reaction rate, which plays an important role in the prediction of the primord…

hep-th2021★ 1 cited

Constraints on Global Symmetry Breaking in Quantum Gravity from Cosmic Birefringence Measurements

James Alvey, Miguel Escudero Abenza

All global symmetries are expected to be explicitly broken by quantum gravitational effects, and yet may play an important role in Particle Physics and Cosmology. As such, any evid…

hep-ph2020★ 56 cited

New Constraints on the Mass of Fermionic Dark Matter from Dwarf Spheroidal Galaxies

James Alvey, Nashwan Sabti, Victoria Tiki +7

Dwarf spheroidal galaxies are excellent systems to probe the nature of fermionic dark matter due to their high observed dark matter phase-space density. In this work, we review, re…

hep-ph2020★ 32 cited

The Axion Quality Problem: Global Symmetry Breaking and Wormholes

James Alvey, Miguel Escudero

Continuous global symmetries are expected to be broken by gravity, which can lead to important phenomenological consequences. A prime example is the threat that this poses to the v…

hep-ph2019★ 170 cited

Refined Bounds on MeV-scale Thermal Dark Sectors from BBN and the CMB

Nashwan Sabti, James Alvey, Miguel Escudero +2

New light states thermally coupled to the Standard Model plasma alter the expansion history of the Universe and impact the synthesis of the primordial light elements. In this work,…

astro-ph.CO2019★ 104 cited

Improved BBN Constraints on the Variation of the Gravitational Constant

James Alvey, Nashwan Sabti, Miguel Escudero +1

Big Bang Nucleosynthesis (BBN) is very sensitive to the cosmological expansion rate. If the gravitational constant took a different value during the nucleosynthesis epoch than…

hep-ph2019★ 73 cited

Light Dark Matter from Inelastic Cosmic Ray Collisions

James Alvey, Miguel Campos, Malcolm Fairbairn +1

Direct detection experiments relying on nuclear recoil signatures lose sensitivity to sub-GeV dark matter for typical galactic velocities. This sensitivity is recovered if there ex…

hep-ph2019★ 21 cited

Linking Scalar Dark Matter and Neutrino Masses with IceCube 170922A

J. B. G. Alvey, M. Fairbairn

Two of the key unresolved issues facing Standard Model physics are (i) the appearance of a small but non-zero neutrino mass, and, (ii) the missing mass problem in the Universe. The…