Branch-Local Seam Stress

SCQG Paper 13 of 28 This paper develops the stress associated with the reciprocal boundary condition in Semantic Commitment Quantum Gravity. Stress describes local energy density, momentum flow and pressure. The model describes one completed universe with two temporal orientations, each with its own forward metric time. The seam pairs the birth boundary of one orientation with the terminal boundary of the other. Its physical response is realized within each orientation. The paper constructs stress from quantum fields near boundaries, localized surfaces, differences between paired holographic screen cells, and causal response. Contributions are expressed on the same spacetime, and shared microscopic terms are subtracted before the total is assembled. Each physical contribution is counted once. Stress follows from a physical action or from a specified constitutive law that relates a system’s state to its response. The construction includes energy and momentum exchange, response after a disturbance, and correlated fluctuations. It retains correlations between the initial metric state and later stress fluctuations. A graph description shows how exchanges between selected sectors cancel while transfers to other local sectors remain in the balance. Relative entropy measures differences between paired states and enters the physical response through an action or constitutive law with the required units. Spatial averages connect the stress tensor to cosmological energy density and pressure. The pressure-to-energy-density ratio, wΘ = pΘ/ρΘ, follows from the chosen physical realization and its exchange law. The paper gives conditions for relaxation, inflation exit, a residual contribution to late acceleration, and the recovery of Einstein gravity at large scales. It also states when early and late responses can belong to one reciprocal metric process. This is Paper 13 of the Semantic Commitment / Quantum Gravity series.