AG Mathematische Physik, Patricia Ribes Metidieri (Nijmegen): Entanglement: ubiquitous, but measurable?

Patricia Ribes Metidieri (Nijmegen)

Entanglement: ubiquitous, but measurable?

Abstract:
It is well known that entanglement is ubiquitous in quantum field theory: even
the simplest states within the simplest field theories are highly entangled. The
foundation of this statement rests on two results: (1) the Reeh-Schlieder
theorem, which shows that all field variables in any one region of spacetime
are entangled with variables in other regions, and (2) the calculations of
entanglement entropy between a region and its complement, which show that
entanglement between adjoining spacetime regions is not just large but UV
divergent. In this talk, I will argue that these results do not provide much
information about the entanglement between individual local degrees of freedom.
I will then present a way of quantifying such entanglement, involving only a
finite number of degrees of freedom, finite regions of space, and quantities
that are directly measurable. I will summarize our understanding both in
(1+D)-dimensional Minkowski spacetime and de Sitter spacetime, paying special
attention to the consequences of the latter in our ability to detect quantum
effects from the inflationary era.