Bruhat-Tits Quantum Processor: Ultrametric Fault-Tolerant Quantum Computation with Holographic Tree Codes
Rowan Brad Quni-Gudzinas
Abstract
We propose a fault-tolerant quantum computing architecture—the Bruhat-Tits Quantum Processor—that exploits the ultrametric geometry of the Bruhat-Tits tree $\mathcal{T}_p$ to achieve quantum error correction thresholds substantially exceeding those of conventional Euclidean-locality codes. The architecture uses holographic perfect-tensor codes on a truncated Bruhat-Tits tree, tree-automorphism logical gates, and fractal-multiplexed readout. We compute bit-flip, depolarizing, independent $X$+$Z$, gate-error, and magic-state distillation thresholds via analytical recursion, exact Gottesman-Knill stabilizer simulation, and Monte Carlo methods. The tree code achieves a bit-flip threshold of $p_c = 50.0\%$ ($4.6\times$ above surface codes at $\sim 10.9\%$), a depolarizing threshold of $p_c = 75.0\%$ ($75\times$ above surface codes at $\sim 1.0\%$), and an independent $X$+$Z$ threshold of $p_c = 17.30\%$. We benchmark the tree code against the surface code at matched physical qubit counts using Monte Carlo simulation with Minimum-Weight Perfect Matching (MWPM) decoding. A logical-level demonstration of Shor’s algorithm for $N = 15$ confirms algorithmic completeness and establishes physical resource requirements. All quantitative claims are verified by self-contained Python simulations. We identify open problems—including perfect tensor existence, tree automorphism gate generation, and physical noise modeling—as directions for future investigation. The architecture’s defining innovation is the use of ultrametricity as a quantum error correction resource: the strong triangle inequality $d(x,z) = \max(d(x,y), d(y,z))$ confines error clusters to disjoint subtrees, enabling parallel, local decoding in $O(s \log s)$ time.