Relativistic Extension of Zero: A Scalar–Tensor Theory of Gravitational Thermodynamics

A covariant scalar–tensor theory of gravity is developed based on the principle of a relativistic zero point, encoded in a dynamical scalar field Θ. The field governs local deviations from a fixed energy–vacuum reference, effectively rendering the zero point of energy and spacetime coordinates frame–dependent. The theory extends the Einstein–Hilbert action through a non–minimal coupling F(Θ)R, incorporating thermal and vacuum energy contributions in a geometrically consistent manner. The framework predicts testable deviations in gravitational wave propagation, black hole thermodynamics, and cosmology, providing a unified approach to gravitational thermodynamics within a relativistic context.