Proximity force approximation for the Casimir energy as a derivative expansion

The proximity force approximation (PFA) has been widely used as a tool to evaluate the Casimir force between smooth objects at small distances. In spite of being intuitively easy to grasp, it is generally believed to be an uncontrolled approximation. Indeed, its validity has only been tested in part...

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Autores principales: Fosco, C.D., Lombardo, F.C., Mazzitelli, F.D.
Formato: JOUR
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_15507998_v84_n10_p_Fosco
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spelling todo:paper_15507998_v84_n10_p_Fosco2023-10-03T16:24:28Z Proximity force approximation for the Casimir energy as a derivative expansion Fosco, C.D. Lombardo, F.C. Mazzitelli, F.D. The proximity force approximation (PFA) has been widely used as a tool to evaluate the Casimir force between smooth objects at small distances. In spite of being intuitively easy to grasp, it is generally believed to be an uncontrolled approximation. Indeed, its validity has only been tested in particular examples, by confronting its predictions with the next-to-leading-order (NTLO) correction extracted from numerical or analytical solutions obtained without using the PFA. In this article we show that the PFA and its NTLO correction may be derived within a single framework, as the first two terms in a derivative expansion. To that effect, we consider the Casimir energy for a vacuum scalar field with Dirichlet conditions on a smooth curved surface described by a function ψ in front of a plane. By regarding the Casimir energy as a functional of ψ, we show that the PFA is the leading term in a derivative expansion of this functional. We also obtain the general form of the corresponding NTLO correction, which involves two derivatives of ψ. We show, by evaluating this correction term for particular geometries, that it properly reproduces the known corrections to PFA obtained from exact evaluations of the energy. © 2011 American Physical Society. Fil:Lombardo, F.C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Mazzitelli, F.D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_15507998_v84_n10_p_Fosco
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
description The proximity force approximation (PFA) has been widely used as a tool to evaluate the Casimir force between smooth objects at small distances. In spite of being intuitively easy to grasp, it is generally believed to be an uncontrolled approximation. Indeed, its validity has only been tested in particular examples, by confronting its predictions with the next-to-leading-order (NTLO) correction extracted from numerical or analytical solutions obtained without using the PFA. In this article we show that the PFA and its NTLO correction may be derived within a single framework, as the first two terms in a derivative expansion. To that effect, we consider the Casimir energy for a vacuum scalar field with Dirichlet conditions on a smooth curved surface described by a function ψ in front of a plane. By regarding the Casimir energy as a functional of ψ, we show that the PFA is the leading term in a derivative expansion of this functional. We also obtain the general form of the corresponding NTLO correction, which involves two derivatives of ψ. We show, by evaluating this correction term for particular geometries, that it properly reproduces the known corrections to PFA obtained from exact evaluations of the energy. © 2011 American Physical Society.
format JOUR
author Fosco, C.D.
Lombardo, F.C.
Mazzitelli, F.D.
spellingShingle Fosco, C.D.
Lombardo, F.C.
Mazzitelli, F.D.
Proximity force approximation for the Casimir energy as a derivative expansion
author_facet Fosco, C.D.
Lombardo, F.C.
Mazzitelli, F.D.
author_sort Fosco, C.D.
title Proximity force approximation for the Casimir energy as a derivative expansion
title_short Proximity force approximation for the Casimir energy as a derivative expansion
title_full Proximity force approximation for the Casimir energy as a derivative expansion
title_fullStr Proximity force approximation for the Casimir energy as a derivative expansion
title_full_unstemmed Proximity force approximation for the Casimir energy as a derivative expansion
title_sort proximity force approximation for the casimir energy as a derivative expansion
url http://hdl.handle.net/20.500.12110/paper_15507998_v84_n10_p_Fosco
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