Modeling a particle detector in field theory

Autor(en)

Fabio Michele Costa, Federico Piazza

Abstrakt

Particle detector models allow us to give an operational definition to the particle content of a given quantum state of a field theory. The commonly adopted Unruh–DeWitt type of detector is known to undergo temporary transitions to excited states even when at rest and in the Minkowski vacuum. We argue that real detectors do not feature this property, as the configuration 'detector in its ground state + vacuum of the field' is generally a stable bound state of the underlying fundamental theory (e.g. the ground state-hydrogen atom in a suitable quantum electrodynamics with electrons and protons) in the non-accelerated case. As a concrete example, we study a local relativistic field theory where a stable particle can capture a light quantum and form a quasi-stable state. As expected, to such a stable particle correspond energy eigenstates of the full theory, as is shown explicitly by using a dressed particle formalism at first order in perturbation theory. We derive an effective model of detector (at rest) where the stable particle and the quasi-stable configurations correspond to the two internal levels, 'ground' and 'excited', of the detector.

Organisation(en)

Quantenoptik, Quantennanophysik und Quanteninformation

Externe Organisation(en)

Perimeter Institute for Theoretical Physics

Journal

New Journal of Physics

Band

11

Anzahl der Seiten

11

ISSN

1367-2630

DOI

https://doi.org/10.1088/1367-2630/11/11/113006

Publikationsdatum

2009

Peer-reviewed

Ja

ÖFOS 2012

103026 Quantenoptik

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/e7985c7b-6b79-418e-ac64-4bac878f2f7e