The Qudit Advantage: System-Level Joules-per-Solution Comparison of a Qudit Architecture Against 17 Conventional Qubit Quantum Computing Platforms

The JPCUB Competitive Landscape v2.0 benchmarked 17 qubit-based quantum computing platforms across the joules-per-solution energy-efficiency metric. This paper extends the JPCUB framework to qudit architectures — d-level quantum systems — and computes a JPCUB estimate for a qudit platform using p-adic stabilizer codes on Bruhat-Tits trees with ultrametric decoding. The qudit platform projects to approximately 10^-5 J/sol versus the 2026 superconducting-qubit floor of 0.05 J/sol. The paper pre-registers an explicit disconfirmation condition and three falsifiable predictions. v0.4: corrected citation key S3 (Fischer et al. — PRX Quantum 4, 030327), see ERRATA.md.