A Strong-Field Spin-Precession Bound on a Pressure-Medium (Khronometric) Extension of General Relativity, and Constraints on Its Remaining Parameter Choices

This unreviewed preprint tests a pressure-medium parameterization of khronometric gravity against solitary-pulsar observations and theoretical stability requirements. Discoveries: Strong-field self-gravity breaks the weak-field spin-precession cancellation on the tested parameter line. At the declared preferred-frame coupling of 10⁻⁷, both tested nonzero-coupling regimes fail the pulsar bounds at leading order in stellar rotation. For the six-derivative zero-coupling branch, the paper computes a positive radiatively generated lapse-inertia coefficient under the tested finite cutoffs and examines its smooth small-coupling limit. Remaining low-energy windows and the calculations needed to decide them are stated explicitly. New tools: To our knowledge, the first strong-field rotating-star spin-precession coefficient and reference table for the tested khronometric parameterization, together with stellar-structure, sensitivity, binary-pulsar and spectral-integral codes. The companion archive includes scripts, inputs, reference outputs and checksum manifests for reproducing the reported results. The calculations use specified stellar models, perturbative approximations and cutoff prescriptions; their limitations are documented throughout. The work has not undergone independent peer review. Text and reference data are licensed under CC BY 4.0; code is licensed under MIT.