On Identifying Background-Structure in Classical Field Theories

Abstract

I argue, however, that there is a proposal that clarifies the feature of Einsteinian gravitation that motivates the concept.

Background Independence in Classical and Quantum Gravity

“…As Pitts states, examples include the identity matrix, the Lorentz matrix diag (−1, 1, 1, 1), fixed Dirac γ µ matrices, Lie group structure constants, and the Kronecker delta and Levi-Civita alternating symbol. Other possible examples of confined objects include the metric signature [18]; 15 and the global topology of spacetime [118,123]. 16 Smolin implies in [123, p. 204] that all such confined objects should ultimately be excised from our final theories of physics -exploring the extent to which this is both true and possible is an interesting task for future pursuit.…”