Quantum Computation in light of a Principle of Least Information and 2 time Gaussian, Symmetric Quantum Mechanics

This tutorial explains, from first principles and with minimal prerequisites, how
a foundational model—“Janus–PLI”—guides practical design choices in quantum
computing (QC). In the model, (i) a Principle of Least Information (PLI) pe-
nalizes gratuitous complexity in laws and boundary conditions, and (ii) quantum
mechanics emerges from a polarization-invariant auxiliary time: reflection positivity
(OS/GNS) and a Gaussian-class influence functional lead to completely positive,
trace-preserving (CPTP) dynamics, strong positivity of the decoherence functional,
the Born rule, and the absence of third-order interference. We translate these
foundations into engineering levers: CP-safe noise kernels, measurement scheduling
using a visibility–information threshold, directional Zeno ratchets (bias without
classical force), MDL/PLI-regularized calibration, and CP-preserving error miti-
gation. The paper includes intuition, worked examples, diagrams, platform notes
(superconducting, ions, photonics), experimental protocols, limitations, FAQs, and
a glossary.