Research
An overview of my research interests and key results.
Auto-generated from recent publications. See InspireHEP for a full list of papers.
The Cosmological Collider
I search for signatures of massive particles produced during cosmic inflation – the “cosmological collider” program. Using both galaxy survey data (BOSS power spectrum and bispectrum) and CMB higher-point functions, I constrain the masses and spins of particles present during inflation, opening a unique observational window into ultra-high-energy particle physics. My recent work extends these searches to the cosmic microwave background and critically assesses how well collider signatures can actually be measured from current data.
Key papers: Philcox 2026, Philcox 2026, Cabass, Philcox, Ivanov et al. 2024
CMB Higher-Point Functions
I build efficient optimal estimators for the CMB bispectrum and trispectrum on the full sky, applicable to both scalar and tensor perturbations. I have used these to place the first constraints on the primordial trispectrum from Planck data, to search for tensor and mixed tensor-scalar non-Gaussianity, and to constrain arbitrary primordial bispectrum shapes without assuming a fixed template.
Key papers: Philcox 2026, Philcox, Zhong & Sirletti 2025, Philcox 2025
Galaxy Power Spectrum and Bispectrum Analysis
I develop optimal, window-free estimators for measuring galaxy clustering statistics and apply them to state-of-the-art survey data. My recent work includes joint power spectrum and bispectrum analyses of BOSS and DESI DR1 data within perturbation theory – now extended to two-loop order – yielding precise constraints on cosmological parameters including the Hubble constant, neutrino masses, dark energy, and primordial non-Gaussianity.
Key papers: Philcox 2026, Ivanov, Sullivan, de Belsunce et al. 2026, Chudaykin, Ivanov & Philcox 2025
Inflation from Galaxy Surveys
I use the galaxy bispectrum from BOSS and DESI data – analyzed within the framework of the effective field theory of large-scale structure – to constrain models of single-field and multifield inflation, including searches for equilateral, folded, and oscillatory primordial signals. This work provides some of the tightest constraints on primordial non-Gaussianity parameters from galaxy clustering.
Key papers: Chen, Chudaykin, Ivanov et al. 2026, Yang & Philcox 2026, Chudaykin, Ivanov & Philcox 2025
Parity Violation in Cosmology
I conduct systematic searches for parity-violating signatures in both galaxy surveys and the CMB. This includes the first measurement of the parity-odd four-point correlation function from BOSS galaxies, a careful assessment of whether that signal could arise from sample variance, and tests of parity using CMB temperature and polarization bispectra.
Key papers: Philcox & Ereza 2024, Philcox & Shiraishi 2023, Philcox 2022
The Hubble Constant and Dark Energy
I have pioneered sound-horizon-independent measurements of the Hubble constant using the matter-radiation equality scale from galaxy surveys, CMB lensing, and supernovae. More recently, I have used full-shape galaxy clustering analyses of DESI data to constrain dark energy, spatial curvature, and neutrino masses, and to test beyond-LCDM physics.
Key papers: Smith, Ivanov, de Belsunce et al. 2026, Chudaykin, Ivanov & Philcox 2025, Philcox, Silverstein & Torroba 2025
Simulation-Based Inference
I develop hybrid simulation-based inference methods that combine analytic likelihoods with neural network emulators, enabling more robust cosmological analyses that go beyond traditional summary statistics – including the simulation-based priors now used in state-of-the-art DESI full-shape analyses.
Key papers: Jacobus, Tucci & Philcox 2026, Chudaykin, Ivanov & Philcox 2026, Zhang, Modi & Philcox 2025