Braking indices as probes of r-mode spin-down in young pulsars — E8 Intelligence Research

We present a timing-based framework for interpreting braking-index measurements in young pulsars within a four-channel spin-down model that includes particle-wind, magnetic-dipole, mass-quadrupole, and current-quadrupole torques. In this formulation, the observed braking index is a torque-weighted average of the channel exponents, allowing equation-of-state-independent constraints on the torque fraction of a possible r-mode-like current-quadrupole component from timing data alone. For a positive, slowly varying secular model, the physically allowed range is 1 ≤ nobs ≤ 7. Within this domain, the lower and capped physical upper bounds on the k=7 torque fraction are f7,min=max[0 Author: Andrew Stewart Caldin, Independent Researcher, UK. Part of the E8 Intelligence Research series. Platform: e8intelligence.com