A general perspective on time observables

A general perspective on time observables

I propose a general geometric framework in which to discuss the existence of time observables. This frameworks allows one to describe a local sense in which time observables always exist, and a global sense in which they can sometimes exist subject to a restriction on the vector fields that they generate. Pauli’s prohibition on quantum time observables is derived as a corollary to this result. ...

A PHENIX perspective on soft observables in Heavy Ion Collisions

We present an overview of measurements from the PHENIX experiment focusing on soft observables in nucleus-nucleus collisions. The excellent particle identification of the PHENIX detector at low and intermediate transverse momentum provide an extensive set of measurements in nucleus-nucleus collisions and baseline measurements in p+p and d+Au collisions. Thermalized particle spectra, strong elli...

Observables IV : The Presheaf Perspective

In this fourth of our series of papers on observables we show that one can associate to each von Neumann algebra R a pair of isomorphic presheaves, the upper presheaf O Rand the lower presheaf O − R , on the category of abelian von Neumann subalgebras of R. Each A ∈ Rsa induces a global section of O R and of O − R respectively. We call them contextual observables. But we show that, in general, ...

On a class of 2-surface observables in general relativity

The boundary conditions for canonical vacuum general relativity is investigated at the quasi-local level. It is shown that fixing the area element on the 2-surface S (rather than the induced 2-metric) is enough to have a well defined constraint algebra, and a well defined Poisson algebra of basic Hamiltonians parameterized by shifts that are tangent to and divergence free on S. The evolution eq...

Diagonalisation of quantum observables on regular lattices and general graphs