A Direct Observational Search Strategy for De-horizoning Transitions: Identifying Pulsar Emergence from Isolated Stellar-Mass Black Hole Candidates

Standard general relativistic frameworks treat the event horizons of stellar-mass black holes as irreversible unidirectional boundaries. However, non-perturbative quantum gravity extensions, semiclassical back-reaction scenarios, and macroscopic topological drain mechanisms predict that non-accreting, isolated black holes experiencing net mass deflation can reach a critical instability threshold (M → M crit ≈ M TOV ). At this boundary, a dynamic phase transition ("de-horizoning") can eject the horizon boundary, relaxing the ultra-dense core into a de-confined nuclear lattice (a nascent magnetar or radio pulsar). Here, bypassing model-dependent interior microphysics, we propose a direct observational archival test to constrain or detect this transition. We outline a falsifiable three-stage observational protocol utilizing existing multi-messenger archives: (i) cataloging isolated black hole candidates identified via photometric/astrometric microlensing (e.g., OGLE, Gaia) with confirmed absence of luminous stellar progenitors; (ii) spatial cross-matching with short-duration, host-less high-energy transients (Fermi-GBM, Swift-BAT); and (iii) targeted, ultra-sensitive radio pulsation searches (MeerKAT, FAST, SKA-precursors) at the quiescent coordinates. This methodology provides a cost-effective, purely empirical test capable of confirming or ruling out non-singular horizon relaxation without invoking unverified cosmological parameters.