Indefinite causal structures for continuous-variable systems

Autor(en)

Flaminia Giacomini, Esteban Castro-Ruiz, Caslav Brukner

Abstrakt

In all our well-established theories, it is assumed that events are embedded in a global causal structure such that, for every pair of events, the causal order between them is always fixed. However, the possible interplay between quantum mechanics and general relativity may require a revision of this paradigm. The process matrix framework keeps the validity of quantum physics locally but does not assume the existence of a global causal order. It allows to describe causal structures corresponding to a quantum superposition of 'A is before B' and 'B is before A'. So far, the framework has been developed only for finite-dimensional systems, and a straightforward generalization to infinite dimensions leads to singularities. Such generalization is necessary for continuous-variable systems and is a prerequisite for quantum fields on indefinite causal structures. Here we develop the process-matrix framework for continuous-variable systems. We encounter and solve the problems of singularities. Moreover, we study an example of a process in infinite dimensions, and we derive correlations exhibiting intereference due to processes in which A is before B and B is before A.

Organisation(en)

Quantenoptik, Quantennanophysik und Quanteninformation

Externe Organisation(en)

Österreichische Akademie der Wissenschaften (ÖAW)

Journal

New Journal of Physics

Band

18

Anzahl der Seiten

8

ISSN

1367-2630

DOI

https://doi.org/10.1088/1367-2630/18/11/113026

Publikationsdatum

11-2016

Peer-reviewed

Ja

ÖFOS 2012

103024 Quantenfeldtheorie, 103025 Quantenmechanik

Schlagwörter

ASJC Scopus Sachgebiete

Allgemeine Physik und Astronomie

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/1f824b48-8b3e-4083-a34f-9a5286597579