Quantum Computing Through the Lens of Three Time Dimensions: Geometric Foundations, Decoherence Mechanisms, and Practical Engineering Proposals

We apply the Three Time Dimensions (3+3) spacetime model to quantum computing, demonstrating that the Bloch sphere used to represent qubit states is geometrically identical to the compact third time dimension S² of the (3+3) model. This identification resolves several foundational puzzles — the two-state structure of qubits, the origin of the Born rule, the mechanism of measurement, and the non-locality of entanglement — without additional postulates. The (3+3) picture further distinguishes three physically distinct decoherence mechanisms with separate origins: T1 energy relaxation from electromagnetic null-arc coupling; T2 dephasing from Higgs l=2 breathing-mode coupling (with coupling amplitude ε_ZPE = 0.127 = m_H/(4v)); and a cosmological floor from the t2 cosmic expansion giving τ_cosm = 1/(α_23 H_0) ≈ 16 Gyr per isolated qubit — comparable to the age of the universe, and therefore negligible as an engineering constraint. From this geometric picture, we derive six practical engineering proposals: (1) operation at the nodal-cone latitude θ = 54.74° = arccos(1/√3) on the Bloch sphere, which geometrically suppresses the dominant phonon-mediated T2 dephasing channel; (2) S²-topological qubits exploiting π_2(S²) = Z, which is strictly stronger than current Majorana/Kitaev approaches based on π_1(S¹) = Z; (3) the trisection qutrit, a naturally 3-fold degenerate three-level system from the SU(3) symmetry of the S² trisection; (4) tunable quantum measurement via controlled t3 entrainment by N apparatus atoms; (5) entanglement coherence that scales with the number of environmental atoms N_env along the path rather than with spatial distance; and (6) a path to room-temperature quantum coherence by suppressing the phonon T2 channel. These proposals are falsifiable and several are testable with existing experimental hardware.