A low-cost torsion balance experiment to detect repulsive gravitational anomalies in rotating superconductors

We propose a low-cost torsion balance experiment to test the quantum gravitodiamagnetic framework published by the Hunan group (Physical Review D, 2024-2026). The target signature is a repulsive force that appears only when a YBCO superconducting disk is rotating at 77 K, facing a passive mass. If detected, this force would be unambiguous — no known force (electromagnetism, Newtonian gravity, Casimir forces) produces repulsion synchronized with superconductor rotation. The experiment costs USD 1,360-1,710, takes 3-4 months, and requires only a torsion balance, YBCO disk, brushless motor, laser pointer, webcam, and liquid nitrogen. No lock-in amplifier, no microwave source, no vacuum chamber. Results are publishable regardless of sign: a null result establishes an upper bound, a positive result would open a new field with implications for propulsion physics and for understanding documented UAP flight characteristics. This document is part of a three-document series. Companion documents: full technical proposal (Doc2) and plain language research summary (Doc3) available in the same Zenodo repository.