Entanglement between smeared field operators in the Klein-Gordon vacuum

Zych, Magdalena, Costa, Fabio, Kofler, Johannes and Brukner, Caslav (2010) Entanglement between smeared field operators in the Klein-Gordon vacuum. Physical Review D: covering particles, fields, gravitation, and cosmology, 81 12: . doi:10.1103/PhysRevD.81.125019


Author Zych, Magdalena
Costa, Fabio
Kofler, Johannes
Brukner, Caslav
Title Entanglement between smeared field operators in the Klein-Gordon vacuum
Journal name Physical Review D: covering particles, fields, gravitation, and cosmology   Check publisher's open access policy
ISSN 1550-7998
2470-0029
Publication date 2010-06-15
Sub-type Article (original research)
DOI 10.1103/PhysRevD.81.125019
Open Access Status Not yet assessed
Volume 81
Issue 12
Total pages 14
Place of publication College Park, MD, United States
Publisher American Physical Society
Language eng
Abstract Quantum field theory is the application of quantum physics to fields. It provides a theoretical framework widely used in particle physics and condensed matter physics. One of the most distinct features of quantum physics with respect to classical physics is entanglement or the existence of strong correlations between subsystems that can even be spacelike separated. In quantum fields, observables restricted to a region of space define a subsystem. While there are proofs on the existence of local observables that would allow a violation of Bell's inequalities in the vacuum states of quantum fields as well as some explicit but technically demanding schemes requiring an extreme fine-tuning of the interaction between the fields and detectors, an experimentally accessible entanglement witness for quantum fields is still missing. Here we introduce smeared field operators which allow reducing the vacuum to a system of two effective bosonic modes. The introduction of such collective observables is motivated by the fact that no physical probe has access to fields in single spatial (mathematical) points but rather smeared over finite volumes. We first give explicit collective observables whose correlations reveal vacuum entanglement in the Klein-Gordon field. We then show that the critical distance between the two regions of space above which two effective bosonic modes become separable is of the order of the Compton wavelength of the particle corresponding to the massive Klein-Gordon field.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Mathematics and Physics
 
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