9 research outputs found
Dynamical locality of the nonminimally coupled scalar field and enlarged algebra of Wick polynomials
We discuss dynamical locality in two locally covariant quantum field
theories, the nonminimally coupled scalar field and the enlarged algebra of
Wick polynomials. We calculate the relative Cauchy evolution of the enlarged
algebra, before demonstrating that dynamical locality holds in the nonminimally
coupled scalar field theory. We also establish dynamical locality in the
enlarged algebra for the minimally coupled massive case and the conformally
coupled massive case.Comment: 39p
On the Reeh-Schlieder Property in Curved Spacetime
We attempt to prove the existence of Reeh-Schlieder states on curved
spacetimes in the framework of locally covariant quantum field theory using the
idea of spacetime deformation and assuming the existence of a Reeh-Schlieder
state on a diffeomorphic (but not isometric) spacetime. We find that physically
interesting states with a weak form of the Reeh-Schlieder property always exist
and indicate their usefulness. Algebraic states satisfying the full
Reeh-Schlieder property also exist, but are not guaranteed to be of physical
interest.Comment: 13 pages, 2 figure
Deformations of quantum field theories on spacetimes with Killing vector fields
The recent construction and analysis of deformations of quantum field
theories by warped convolutions is extended to a class of curved spacetimes.
These spacetimes carry a family of wedge-like regions which share the essential
causal properties of the Poincare transforms of the Rindler wedge in Minkowski
space. In the setting of deformed quantum field theories, they play the role of
typical localization regions of quantum fields and observables. As a concrete
example of such a procedure, the deformation of the free Dirac field is
studied.Comment: 35 pages, 3 figure
Dynamical locality and covariance: What makes a physical theory the same in all spacetimes?
The question of what it means for a theory to describe the same physics on
all spacetimes (SPASs) is discussed. As there may be many answers to this
question, we isolate a necessary condition, the SPASs property, that should be
satisfied by any reasonable notion of SPASs. This requires that if two theories
conform to a common notion of SPASs, with one a subtheory of the other, and are
isomorphic in some particular spacetime, then they should be isomorphic in all
globally hyperbolic spacetimes (of given dimension). The SPASs property is
formulated in a functorial setting broad enough to describe general physical
theories describing processes in spacetime, subject to very minimal
assumptions. By explicit constructions, the full class of locally covariant
theories is shown not to satisfy the SPASs property, establishing that there is
no notion of SPASs encompassing all such theories. It is also shown that all
locally covariant theories obeying the time-slice property possess two local
substructures, one kinematical (obtained directly from the functorial
structure) and the other dynamical (obtained from a natural form of dynamics,
termed relative Cauchy evolution). The covariance properties of relative Cauchy
evolution and the kinematic and dynamical substructures are analyzed in detail.
Calling local covariant theories dynamically local if their kinematical and
dynamical local substructures coincide, it is shown that the class of
dynamically local theories fulfills the SPASs property. As an application in
quantum field theory, we give a model independent proof of the impossibility of
making a covariant choice of preferred state in all spacetimes, for theories
obeying dynamical locality together with typical assumptions.Comment: 60 pages, LaTeX. Version to appear in Annales Henri Poincar