Topologically Protected Vortex Qubits in Logarithmic Spiral Geometries: Toward Intermediate-Temperature Quantum Computing in High-Tc/TI Heterostructures

AbstractWe propose a topological qubit architecture based on Majorana zero modes(MZMs) confined within Josephson vortices in a hybrid heterostructure of high-Tcsuperconductor YBa2Cu3O7−δ (YBCO) and topological insulator Bi2Se3. The cen-tral innovation is a lithographically defined logarithmic spiral geometry that createsa topologically nontrivial phase space for vortex dynamics. We demonstrate thatthis geometry induces an effective Berry curvature in the vortex configuration space,providing geometric protection against thermal perturbations. Through a rigorousanalysis incorporating Chern number calculations, we show that the combination ofmaterial topology (MZMs) and geometric topology (spiral manifold) enables coher-ent qubit operation at temperatures up to T ∼ 40-50 K, significantly higher thanconventional MZM platforms. We derive effective Hamiltonians, estimate decoher-ence times, and propose experimental protocols for braiding operations and readout.This work establishes a theoretical framework for exploiting geometric topology asa resource for quantum information protection.