On the notion of "the same physics in all spacetimes"

TY - GEN

T1 - On the notion of "the same physics in all spacetimes"

AU - Fewster, Chris J

PY - 2012

Y1 - 2012

N2 - Brunetti, Fredenhagen and Verch (BFV) have shown how the notion of local covariance for quantum field theories can be formulated in terms of category theory: a theory being described as a functor from a category of spacetimes to a category of (C)-algebras. We discuss whether this condition is sufficient to guarantee that a theory represents ‘the same physics’ in all spacetimes, giving examples to show that it does not. A new criterion, dynamical locality, is formulated, which requires that descriptions of local physics based on kinematical and dynamical considerations should coincide. Various applications are given, including a proof that dynamical locality for quantum fields is incompatible with the possibility of covariantly choosing a preferred state in each spacetime. As part of this discussion we state a precise condition that should hold on any class of theories each representing the same physics in all spacetimes. This condition holds for the dynamically local theories but is violated by the full class of locally covariant theories in the BFV sense. The majority of results described form part of forthcoming papers with Rainer Verch [16].

AB - Brunetti, Fredenhagen and Verch (BFV) have shown how the notion of local covariance for quantum field theories can be formulated in terms of category theory: a theory being described as a functor from a category of spacetimes to a category of (C)-algebras. We discuss whether this condition is sufficient to guarantee that a theory represents ‘the same physics’ in all spacetimes, giving examples to show that it does not. A new criterion, dynamical locality, is formulated, which requires that descriptions of local physics based on kinematical and dynamical considerations should coincide. Various applications are given, including a proof that dynamical locality for quantum fields is incompatible with the possibility of covariantly choosing a preferred state in each spacetime. As part of this discussion we state a precise condition that should hold on any class of theories each representing the same physics in all spacetimes. This condition holds for the dynamically local theories but is violated by the full class of locally covariant theories in the BFV sense. The majority of results described form part of forthcoming papers with Rainer Verch [16].

M3 - Conference contribution

SN - 978-3-0348-0042-6

SP - 207

EP - 227

BT - Quantum Field Theory and Gravity. Conceptual and mathematical advances in the search for a unified framework. The volume emerged from the international conference "Quantum Field Theory and Gravity" held in Regensburg 28 September - 1 October 2010

A2 - Finster, F

A2 - Mueller, O

A2 - Nardmann, M

A2 - Tolksdorf, J

A2 - Zeidler, E

PB - Birkhauser

ER -