قد يكون الكون قد تجمد في بداية حارة سريع

الملخص الأصلي

كما كتبه المؤلفون، بالإنجليزية arXiv:2608.07318v1

Gravitational caloric theory (GCT) extends general relativity by introducing a vector field $$S_\mu$$ that is sourced by and non-minimally coupled to the fluid sector, while preserving covariant conservation of the standard fluid energy-momentum tensor. The initial motivation is to trigger early dark energy (EDE) using the total fluid equation of state that encodes the cosmic radiation-matter transition, thereby addressing the associated coincidence problem. The EDE dynamics are analyzed in detail by recasting the background evolution equations as a two-dimensional dynamical system. Poincar\'e compactification probes the global structure of this system and illustrates the role of critical points at infinity in shaping the phase portrait. There are two cosmological applications beyond EDE, both belonging to a broader family of energy-cancelling solutions in which conventional energy components (e.g., the cosmological constant $$\Lambda$$ or an ideal fluid) preferentially excite $$S_\mu$$ rather than sourcing spacetime curvature. First, the $$\Lambda$$-cancelling solution corresponds to the so-called self-tuning mechanism proposed to address the old cosmological constant problem. A major limitation is that our present realization cannot enter the standard hot Big Bang phase and therefore should not be regarded as a complete self-tuning solution. Second, inspired by a nontrivial critical point at infinity in the EDE phase portrait, we propose an \textit{Early Static Hot Universe} in which $$S_\mu$$ offsets the gravitational effect of ordinary hot gas, yielding quasi-static expansion with a decreasing comoving Hubble radius that can address the horizon problem. This scenario offers an alternative to inflation. This paper opens several avenues for further investigation of GCT, including cosmology, gravitational waves, and compact objects. (Abstract abridged to meet arXiv limits.)