Speaker
Description
General Relativity, despite its successes, violates the Mach principle by admitting vacuum solutions where spacetime curvature exists without matter. Entangled Relativity was proposed as a Machian alternative: the action is constructed so that no consistent matter‑free theory can be defined. Recently, an extension of Entangled Relativity was introduced that incorporates a positive cosmological constant while preserving this Machian property. Remarkably, for matter fields satisfying the on‑shell condition $L_m = T$ (e.g., dust and radiation), the theory dynamically reduces to General Relativity with a positive cosmological constant. The dimensionful cosmological constant is replaced by a single dimensionless parameter, from which an effective $\tilde{\Lambda}$ emerges in the field equations. This framework therefore reproduces the successful $\Lambda CDM$ phenomenology in the regimes where matter fulfills $L_m = T$, yet it remains fundamentally different: it involves one fewer free parameter and inherently links the existence of spacetime to the presence of matter. I will present the key features of this extended theory, discuss how it respects the relativity of inertia, and outline its potential observational implications.