Fractal-Curvature Photonic Qubit: Self-Similar Geometry as Magnetic-Field-Free Topological Protection
PREZAT, PASCAL
Abstract
We introduce a topological qubit encoded in the curvature of a polariton supersolid imprinted onto a self-similar fractal mirror (Hausdorff dimension 2.3). The effective quantum metric inherits the fractal spectrum, yielding a power-law decoherence rate Γeff(L) = ηΓ0(L/L0)−0.48. Combined with bi-split laser echo and undetected twin-photon management we predict T2 ≥ 12ms and two-qubit gate fidelity F ≥ 99.97% at 4K without external magnetic field. The whole stack is CMOS-back-end compatible and deployable on silicon-photonic or free-space military links.