2015/03/08 by Sean Gryb, Karim P. Y. Thébault · 3 citations
Physics and Astronomy · #Noncommutative and Quantum Gravity Theories #Cosmology and Gravitation Theories #Relativity and Gravitational Theory
paper · doi:10.1093/bjps/axv009
On one popular view, the general covariance of gravity implies that change is relational in a strong sense, such that all it is for a physical degree of freedom to change is for it to vary with regard to a second physical degree of freedom. At a quantum level, this view of change as relative variation leads to a fundamentally timeless formalism for quantum gravity. Here, we will show how one may avoid this acute ‘problem of time’. Under our view, duration is still regarded as relative, but temporal succession is taken to be absolute. Following our approach, which is presented in more formal terms in (Gryb and Thébault [2014]), it is possible to conceive of a genuinely dynamical theory of quantum gravity within which time, in a substantive sense, remains. 1 Introduction 1.1 The problem of time 1.2 Our solution 2 Understanding Symmetry 2.1 Mechanics and representation 2.2 Freedom by degrees 2.3 Voluntary redundancy 3 Understanding Time 3.1 Change and order 3.2 Quantization and succession 4 Time and Gravitation 4.1 The two faces of classical gravity 4.2 Retaining succession in quantum gravity 5 Discussion 5.1 Related arguments 5.2 Concluding remarks