2009/10/07 by Sonia Markes, Lucien Hardy, Lucién Hardy
Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Quantum Mechanics and Applications #Statistical Mechanics and Entropy #gr-qc
paper · pdf · doi:10.1088/1742-6596/306/1/012043
published as J.Phys.Conf.Ser.306:012043,2011 · 11 pages, 2 figures
arxiv created 2009/10/07 · openalex publication_date 2011/07/08 · arxiv updated 2011/07/13 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
Any theory with definite causal structure has a defined past and future, be it defined by light cones or an absolute time scale. Entropy is a concept that has traditionally been reliant on a definite notion of causality. However, without a definite notion of causality, the concept of entropy is not all lost. Indefinite causal structure results from combining probabilistic predictions and dynamical space-time. The causaloid framework lays the mathematical groundwork to be able to treat indefinite causal structure. In this paper, we build on the causaloid mathematics and define a causally-unbiased entropy for an indefinite causal structure. In defining a causally-unbiased entropy, there comes about an emergent idea of causality in the form of a measure of causal connectedness, termed the Q factor.