Christopher Ewasiuk

👤 About

I'm a computational physicist finishing my PhD at UC Santa Cruz, where my research centers on black hole dynamics and gravitational waves. My work sits at the boundary between theory and implementation — 7 publications (5 first-author) in Physical Review D, JHEP, JCAP and recent preprints in quantum mechanics and GW transients.

My technical work is about building frameworks that expose where models fail: matched filtering for weak-signal detection, evaluation pipelines stress-tested across thousands of noise realizations, and simulation tools extended into regimes the original codebases weren't designed for. Cross-institutional work at ADMX and Fermilab.

Outside physics: I won top project at the Erdős Institute among ~200 PhD candidates — a 3D deep learning pipeline for MRI brain tumor segmentation from scratch. Dice = 0.83, 86% precision on held-out data.

Actively looking for Research Scientist and Research Engineer roles in the SF Bay Area — AI for science, evaluation infrastructure, ML systems.

📡 Signal Detection

🌌 Gravitational Waves

🧠 Deep Learning

⚙️ Eval Pipelines

🔬 ADMX · Fermilab

🖥 Projects

Signal Processing · Machine Learning · ADMX · SLAC

Gravitational Wave Detection Pipeline

End-to-end signal analysis and ML classification system for searching gravitational waves via resonant microwave cavity detectors, combining a matched filter pipeline with a gradient-boosted classifier to recover sub-threshold candidates and reject RFI false positives.

Matched filtering across multi-terabyte experimental datasets with FFT binning, Welch PSD estimation, robust stacking, and receiver calibration
Synthetic injection pipeline generating thousands of noise realizations across SNR for stress-testing models
XGBoost classifier trained on morphological features of the matched-filter SNR time series, defining a four-quadrant candidate space that isolates genuine signals from RFI-driven false positives and sub-threshold anomalies
Deployed as part of the ADMX Run 1B reanalysis: first ML-assisted GW candidate classification from a microwave cavity detector in the GHz band

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Simulation · Physical Review D

BlackHawk Extension: Black Hole Simulation Framework

Extended a widely-used open-source codebase into a physical regime it was never designed for — the first computational framework of its kind for charged, spinning black hole evolution.

Overhauled core dynamics to model charged charge-depletion, covering spin evolution and time evolution of charged configurations
ODE solvers, parameter sweeps, interpolation across physically motivated initial conditions
Results published first-author in Physical Review D

★ Top Project — Erdős Institute (~200 PhDs)

Deep Learning · PyTorch

3D Brain Tumor Segmentation 🧠

End-to-end volumetric MRI segmentation pipeline built entirely from scratch. Dice = 0.83, 86% precision on held-out data across 500 patients and 4 MRI modalities.

Composite BCE + Dice loss to handle severe class imbalance between tumor and non-tumor regions
GPU-accelerated 3D U-Net architecture
Full pipeline: data ingestion → training → threshold optimization → inference evaluation

Quantum Theory · arXiv 2026

Ghost Stability — Exact Operator Conservation 👻

Proved a rigorous quantum stability result for ghost-coupled systems, showing instabilities are not kinematically inevitable but depend on whether dynamics allow uncontrolled energy transfer.

Exact conservation law: classical conserved quantity lifts to a quantum operator commuting with the Hamiltonian, with no ℏ corrections
Rigorous, state-independent upper bound on mean-squared phase-space radius for all time
Three independent numerical frameworks (Heisenberg, Schrödinger, Fock-space) confirm wavepacket confinement below the analytic bound

📄 Publications

2026

1st Author

Ghost Degrees of Freedom Without Quantum Runaway: Exact Moment Bounds from an Operator Conservation Law

C. Ewasiuk, S. Profumo

arXiv:2604.21348 [quant-ph]

arXiv PDF

2026

1st Author

Quantum Tunneling of Primordial Black Holes to White Holes: Rates, Constraints, and Implications for Fast Radio Bursts

C. Ewasiuk, S. Profumo

arXiv:2603.22516 [gr-qc]

arXiv PDF

2026

High-Frequency Gravitational Wave Transients from Superradiance

H. Su, L. Brown, C. Ewasiuk, S. Profumo

arXiv:2604.01407 [gr-qc]

arXiv PDF

2025

1st Author

Precision Gravity Constraints on Large Dark Sectors

C. Ewasiuk, S. Profumo

JHEP 10 (2025) 0925 · arXiv:2509.02801

arXiv PDF Journal

2025

1st Author

Dark-Sector Modifications to Kerr and Reissner–Nordström Black Hole Evaporation

C. Ewasiuk, S. Profumo

Phys. Rev. D 111 (2025) 015008 · arXiv:2505.04812

arXiv PDF Journal

2025

Maximal Gravitational Wave Signal from Asteroid-Mass Primordial Black Hole Mergers at Resonant Microwave Cavities

S. Profumo, L. Brown, C. Ewasiuk, S. Ricarte, H. Su

Phys. Rev. D 111 (2025) 063072 · arXiv:2410.15400

arXiv PDF Journal

2025

1st Author

Constraints on the Maximal Number of Dark Degrees of Freedom from Black Hole Evaporation, Cosmic Rays, Colliders, and Supernovae

C. Ewasiuk, S. Profumo

Phys. Rev. D 111 (2025) 015008 · arXiv:2409.11359

arXiv PDF Journal

✉️ Contact

Finishing my PhD at UC Santa Cruz (expected 2026) and actively exploring Research Scientist and Research Engineer roles in the SF Bay Area.

Particularly interested in AI for science, evaluation infrastructure, and ML systems. Cross-institutional work at ADMX and Fermilab. Email is the best way to reach me.

↓ Download Resume

Full publication record

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Erdős Institute

Top Project Certificate