The Vacuum Zero-Sum Principle: A Unified Constraint on Speculative Couplings in Entangled-Spacetime Theories

What if a single equation could solve the cosmological constant problem — the worst prediction in all of physics (off by 10¹²³)? This paper introduces the Vacuum Zero-Sum Principle (VZSP), a deceptively simple algebraic constraint — Σ γᵢ ⟨Oᵢ⟩₀ = 0 — that governs the full set of speculative coupling constants when quantum-gravitational, information-theoretic, and entanglement-based terms are added to Einstein's field equations. By demanding only that empty spacetime stays flat and Lorentz-invariant, we show this single condition: - Resolves the cosmological constant problem at tree level — no fine-tuning - Connects quantum entanglement to spacetime geometry via the ER=EPR conjecture - Mimics supersymmetric cancellation — without requiring a single superpartner - Collapses a six-parameter landscape into one free parameter — yielding testable predictions - Reframes dark energy as an information-geometric effect We derive concrete experimental signatures for black hole thermodynamics, vacuum stability, and dark energy phenomenology. A new principle. One equation. Zero vacuum energy. Keywords: quantum gravity, cosmological constant problem, ER=EPR, entangled spacetime, vacuum energy, dark energy, Lorentz invariance, zero-sum constraint