2002/11/25 by Mario Castagnino, Luis Lara, Olímpia Lombardi +1 · 1 citation
Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Cosmology and Gravitation Theories #Relativity and Gravitational Theory #quant-ph
paper · pdf · doi:10.1088/0264-9381/20/2/310
published as Class.Quant.Grav. 20 (2003) 369-392
arxiv created 2002/11/25 · openalex publication_date 2003/01/03 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
In this paper, we address the problem of the arrow of time from a cosmological point of view, rejecting the traditional entropic approach that defines the future direction of time as the direction of the entropy increase: from our perspective, the arrow of time has a global origin and it is an intrinsic, geometrical feature of spacetime. Time orientability and the existence of a cosmic time are necessary conditions for defining an arrow of time, which is manifested globally as the time asymmetry of the universe as a whole, and locally as a time-asymmetric energy flux. We also consider arrows of time of different origins (quantum, electromagnetic, thermodynamic, etc) showing that they can be non-conventionally defined only if the geometrical arrow is previously defined.