A Modular Software Stack for Quantum Computing

Current quantum software architectures implicitly assume the Born rule as a fundamental and universally valid axiom governing measurement statistics. In practice, however, quantum processors operate in driven, noisy, and often nonequilibrium regimes where this assumption lacks a clear physical justification. In this note we propose a Modular Software Stack for Quantum Systems, in which the Born rule is reinterpreted as an equilibrium fixed point associated with modular (KMS) balance. Deviations from equilibrium are quantified through outcome-resolved modular imbalances derived from experimentally reconstructed reduced states. The proposed stack introduces a modular diagnostics layer that enables regime classification, principled deformation of measurement statistics, and modular-aware control, without modifying unitary dynamics, projective measurement, locality, or no-signalling. The framework provides a physically grounded bridge between quantum software, nonequilibrium thermodynamics, and operator-algebraic foundations of quantum theory.