3 papers
hep-th2025
Semifinite von Neumann algebras in gauge theory and gravity
Shadi Ali Ahmad, Marc S. Klinger, Simon Lin
von Neumann algebras have been playing an increasingly important role in the context of gauge theories and gravity. The crossed product presents a natural method for implementing c…
hep-th2024
Quantum Reference Frames from Top-Down Crossed Products
Shadi Ali Ahmad, Wissam Chemissany, Marc S. Klinger +1
All physical observations are made relative to a reference frame, which is a system in its own right. If the system of interest admits a group symmetry, the reference frame observi…
hep-th2024
Crossed product algebras and generalized entropy for subregions
Shadi Ali Ahmad, Ro Jefferson
An early result of algebraic quantum field theory is that the algebra of any subregion in a QFT is a von Neumann factor of type III, in which entropy cannot be well-defined bec…